Chiari-Like Malformation (CM) & Syringomyelia (SM) and the Cavalier King Charles Spaniel | Veterinary Resources

Chiari-Like Malformation (CM) & Syringomyelia (SM) and the Cavalier King Charles Spaniel | Veterinary Resources
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Chiari-like Malformation (CM) and Syringomyelia (SM)  in the
Cavalier King Charles Spaniel
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Veterinary Resources
This is a list of citations and summaries of veterinary research
journal articles which are applicable to Chiari-like malformation (CM)
and syringomyelia (SM) and
cavalier King Charles spaniels.
This list is in chronological order, from 1974 to the present, with the most
recent additions added at the bottom of this page. Hyper-linked titles
are linked to the actual articles which are available on-line.
1974 - 2002
The hitch-hiking effect of a favourable gene
. John Maynard Smith, John
Haigh. Genetics Res. February 1974; doi: 10.1017/S0016672300014634. Quote: When a selectively favourable gene
substitution occurs in a population, changes in gene frequencies will occur
at closely linked loci. In the case of a neutral polymorphism, average
heterozygosity will be reduced to an extent which varies with distance from
the substituted locus. The aggre- gate eifect of substitution on neutral
polymorphism is estimated; in populations of total size 106 or more (and
perhaps of 104 or more), this eifect will be more important than that of
random fixation. This may explain why the extent of polymorphism in natural
populations does not vary as much as one would expect from a consideration
of the equilibrium between mutation and random fixation in populations of
different sizes. For a selectively maintained polymorphism at a linked
locus, this process will only be important in the long run if it leads to
complete fixation. If the selective coefficients at the linked locus are
small compared to those at the substituted locus, it is shown that the
probability of complete fixation at the linked locus is approximately exp (--
Nc), where c is the recombinant fraction and N the population size. It
follows that in a large population a selective substitution can occur in a
cistron without eliminating a selectively maintained polymorphism in the
same cistron.
Mechanism of the decrease in intracranial
pressure as affected by furosemide
. Pinegin
LE, Dolzhenko DA, Natochin IuV. Biull Eksp Biol Med 1984;98:682-685.
Furosemide lowers intracranial pressure by inhibiting CSF production
Lorenzo AV, Hornig G, Zavala LM, et al. Z Kinderchir 1986;41(Suppl 1):10-12.
Dorsal notch of foramen magnum due to incomplete ossification of
supraoccipital bone in dogs
. Watson, A.G., De Lahunta, A., and Evans,
H.E. J. Small Anim. Prac. 1989 30:666-673.
Effect of histamine H2 receptor antagonists on the secretion of
cerebrospinal fluid in the cat
. Naveh Y, Kitzes R, Lemberger A,
Ben-David S, Feinsod M. J Neurochem. 1992 Apr;58(4):1347-52.
Occipital dysplasia and associated cranial spinal cord abnormalities
in two dogs
. Rodney S. Bagley, Michael L. Harrington, Russell L.
Tucker, Ronald D. Sande, Charles R. Root, Robert W. Kramer. Vet. Rad. &
Ultra. Sept 1996; 37(5): 359. Quote: "Occipital dysplasia was found in
association with cervical spinal cord abnormalities in two dogs. One dog
presented for tetraparesis and cervical hyperesthesia, the other [a
Yorkshire terrier] for historical cervical hyperesthesia and mild
paraparesis. In dog 1, a midline cervical spinal cord defect consistent
with a communicating syrinx was found. In the other dog, a presumptive
syringo/hydromyelia of the cervical spinal cord was found on magnetic
resonance imaging. While occipital dysplasia alone is not thought to
cause any clinical abnormalities, the dogs of this report suggest that
intramedullary central nervous system abnormalities may be present
concurrently with occipital dysplasia and should be considered as a
possible cause of the clinical signs. The relationship between occipital
dysplasia and syringo/hydromyelia in these dogs remains unclear,
however, similar associated abnormalities are occasionally found in
humans with Chiari malformation."
Hydromyelia in the dog
. Robert M. Kirberger, Linda S. Jacobson,
Jeremy V. Davies, Jean Engela. Vet. Radiology & Ultrasound. January
1997;38(1):30-38. Quote: "Hydromyelia is a dilation of the spinal cord
central canal. In man this may be due to congenital malformations such
as Dandy-Walker syndrome and Chiari malformations or may be acquired as
result of infection, trauma or neoplasia. In dogs hydromyelia may be
accidentally diagnosed during routine cisterna magna myelography.
Hydromyelia, and its possible etiology, may be confirmed by means of
computed tomography or magnetic resonance imaging. Three dogs with
hydromyelia {two Maltese poodles and one King Charles spaniel] due to
differing etiologies are described."
Persistent scratching in
Cavalier King Charles spaniels
Rusbridge C. Vet Rec. Aug 1997;141(7):179.
Different effects of omeprazole and Sch 28080 on
canine cerebrospinal fluid production
Javaheri S., Corbett W. S.,
Simbartl L. A., Mehta S., Khosla A. Brain Research 1997; 754(1-2); 321-324.
Quote: "We investigated the effects of omeprazole and Sch 28080, a more
specific and a more potent inhibitor of K+,H+-ATPase than omeprazole, in
canine cerebrospinal fluid (CSF) production. ... [T]he percent
decreases in CSF production in the omeprazole treated group were ...
significantly more than the respective values in the control group. ... We
conclude that in the canine model, physiological doses of omeprazole
decrease CSF production by about 26. However, the effect is independent of
the K+,H+-ATPase activity, since Sch 28080 which is more potent than
omeprazole did not significantly affect CSF production."
A syndrome of syringomyelia in the
cavalier King Charles spaniel
, and
its treatment by syringo-subarachnoid shunting
. Skerritt GC, Hughes D:
In Proceedings from the 12th Annual Symposium of the European Society of
Veterinary Neurology, Vienna, 23: 1998.
Syringohydromyelia in
Cavalier King Charles spaniels
Rusbridge C, MacSweeny JE, Davies JV, Chandler K, Fitzmaurice SN, Dennis R,
Cappello R, Wheeler SJ. J Am Anim Hosp Assoc. 2000 Jan-Feb;36(1):34-41.
Chiari 1/syringomyelia complex in a King Charles Spaniel
Churcher RK, Child G. Aust Vet J. 2000 Feb;78(2):92-5. Quote: "A 9-year-old
King Charles Spaniel presented with a history of progressive forelimb
weakness and paroxysmal involuntary flank scratching over a 2-year period.
Neurological examination suggested a myelopathy of C1 to C4 spinal cord
segments. Advanced imaging studies revealed hydrocephalus, caudal herniation
of part of the caudal lobe of the cerebellum through the foramen magnum and
marked syrinx formation to the level of the caudal thoracic spine,
resembling Arnold-Chiari malformation with secondary hydromyelia in humans.
Mechanical obstruction at the craniocervical junction, altering CSF flow
dynamics, may lead to syrinx formation. Response to diuretic therapy was
moderate but surgical decompression may offer better long term prognosis."
Dorsal dens angulation and a Chiari type malformation in a
Cavalier
King Charles Spaniel
.  Bynevelt M, Rusbridge C, Britton J. Vet Radiol
Ultrasound. 2000 Nov-Dec;41(6):521-4.
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2003
Primary secretory otitis media in the
Cavalier King Charles spaniel
a review of 61 cases
.  Stern-Bertholtz W.; Sjostrom L.; Wallin
Håkanson N.  J Small Anim. Prac., June 2003, 44(6): 253-256(4).
Hereditary aspects of occipital bone hypoplasia and syringomyelia (Chiari
type I malformation) in
cavalier King Charles spaniels
.  Rusbridge
C, Knowler SP. Vet Rec. Jul 2003;153(4):107-12.
Neurological signs and results of magnetic resonance imaging in 40
cavalier King Charles spaniels
with Chiari type 1-like malformations
Lu D, Lamb CR, Pfeiffer DU, Targett MP. Vet Rec. Aug 2003;153(9):260-3.
Quote: In human beings a Chiari type 1 malformation is a developmental
condition characterised by cerebellar herniation and syringohydromyelia.
Abnormalities compatible with such a malformation were identified by
magnetic resonance imaging in
39 cavalier King Charles spaniels
with neurological signs and in one neurologically normal
cavalier
King Charles spaniel
that was examined postmortem. The dogs with
these abnormalities had a wide variety of neurological signs, but there was
no apparent correlation between the neurological signs and the severity of
cerebellar herniation, syringohydromyelia or hydrocephalus.
Suboccipital
Craniectomy
and Cranial Dorsal Laminectomy as a Treatment Option for
Chiari Type I Malformation Malformation In the
Cavalier
King Charles Spaniel
. K. Vermeersch; L. Van Ham; J. Caemaert;
M. Tshamala; O. Taeymans; S. Bhatti; I. Polis1. ESVN 2003 Symposium Abstract
14, J.Vet.Int.Med. 19(2). Quote: "Syringohydromyelia combined with
cerebellar tonsil herniation, known as Chiari type I malformation (CIM) is
known to occur in
Cavalier King Charles spaniels
in many
countries. The dogs either have progressive cranial (eg, facial deficits,
seizures, vestibular syndrome) or spinal (eg, hyperesthesia with persistent
scratching of shoulder and neck region) symptoms. Diagnosis is best made by
magnetic resonance imaging (MRI): fluid-filled cavity within the spinal cord
and cerebellar tonsil herniation. As therapeutic options medical treatment
with corticosteroids, acetazolamide, NSAIDs or oral opioids may give an
improvement but most often not a resolution of signs. It is thought that
syrinx formation in humans and dogs with CIM occurs secondary to partial
obstruction of CSF flow at the cranio-cervical junction. Therefore, in human
medicine, a suboccipital craniectomy and cranial dorsal laminectomy with
opening of the dura mater is the procedure of choice for surgical treatment
of CIM. This surgical technique was performed on
4 Cavalier King
Charles spaniels
diagnosed with Chiari type I malformation by
symptoms (scratching of neck region) and by MRI. The dogs were evaluated
neurologically 24 hours, 1 month and 3 months postoperatively. Control MRI
took place 3 months postoperatively. Three dogs recovered uneventfully from
anesthesia. The fourth dog was euthanized within 24 hours after surgery at
owners request due to progressive seizures and decreased capability of
oxygen saturation. Neurologically, the 3 dogs did worse 24 hours after
surgery (neck pain, neck weakness and head tilt), improved gradually and by
3 months postoperatively, achieved the same neurological state as before
surgery. Control MRI of the 3 dogs at that time showed no regression of
syrinx size. The results of this study indicate that there is no improvement
on short term basis in either syrinx size or clinical symptoms after
surgical intervention with a suboccipital craniectomy and cranial dorsal
laminectomy with opening of the dura. Seen the progressive nature of the
disorder, follow-up over a longer period of time is necessary to see if this
surgical technique may influence the progression of syrinx formation and
clinical signs in C
avalier King Charles spaniels
with
Chiari type I malformation."
Sound Wave Therapy Not So Shocking
. Kate Chope, Jose M.
García-López. Tufts Vety School,  Dec 2003 Case Report.
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2004
Gabapentin is a first line drug for the treatment of neuropathic pain
in spinal cord injury
. Levendoglu F, Ogun CO, Ozerbil O, et al. Spine
2004;29:743-751.
Amantadine, an N-methyl-d-aspartate antagonist, for treatment of
chronic neuropathic pain in a dog
. Madden M, Gurney M, Bright S. Vet.
Anaesthesia & Analgesia. March 2014;41:440-1.
Suboccipital craniectomy, dorsal laminectomy of C1, durotomy and
dural graft placement as a treatment for syringo-hydromyelia with cerebellar
tonsil herniation in
Cavalier King Charles spaniels
.  Vermeersch
K, Van Ham L, Caemaert J, Tshamala M, Taeymans O, Bhatti S, Polis I. Vet
Surg. 2004 Jul-Aug;33(4):355-60. Quote: "Objective-- To evaluate
retrospectively the efficacy of the suboccipital craniectomy and dorsal
laminectomy of C1 with durotomy and placement of a dural graft for treatment
of syringohydromyelia (SHM) because of cerebellar tonsil herniation in
Cavalier King Charles spaniels (CKCS)
. This technique is
used with great success in human medicine. Study Design--
Four CKCS
diagnosed by Magnetic resonance imaging (MRI) of SHM because of cerebellar
tonsil herniation and not responsive to medical therapy underwent a
suboccipital craniectomy and dorsal laminectomy of C1 (2 dogs) and of C1 and
partial C2 (2 dogs) with durotomy and placement of a dural graft. Three dogs
were evaluated neurologically 24 hours, 1 month, and 3 months
postoperatively and evaluations were compared with preoperative neurological
examination. Repeat MRI took place 3 months postoperatively. Results--
Neurological examinations showed neither improvement nor progression of
clinical signs 3 months postoperatively. MRI showed no regression of syrinx
size 3 months postoperatively. Conclusion-- Improvement was not seen. Given
the progressive nature of the disorder, evaluation over a longer period of
time is necessary to detect if progression has stopped. Some modification to
the surgical technique is needed to accomplish the same results as in human
medicine. A study of a larger population is needed to attain more reliable
information. Clinical Relevance-- Suboccipital craniectomy and dorsal
laminectomy of C1 with durotomy and placement of a dural graft is a feasible
technique in CKCS, but needs some modification to accomplish the same
results as in human medicine."
Inheritance of occipital bone hypoplasia (Chiari type I malformation)
in
Cavalier King Charles Spaniels
Rusbridge C, Knowler SP.
J Vet Intern Med. 2004 Sep-Oct;18(5):673-8. Quote: Occipital bone hypoplasia
with foramen magnum obstruction and secondary syringomyelia (SM) is a common
condition in the
Cavalier King Charles Spaniel (CKCS)
that
is similar to human Chiari type I malformation. A worldwide family tree of
more than 5,500
CKCSs
spanning a maximum of 24 generations
was established by obtaining pedigree information from 120 dogs diagnosed
with SM secondary to occipital bone hypoplasia. ... The study is unusual
because the complete pedigrees of dogs affected with SM secondary to
occipital hypoplasia are known from the time of derivation of the breed from
King Charles Spaniels
in the 1930s. ... The ongoing study
showed 6 of 8 great grandparents of all affected dogs could be traced back
to 2 female ancestors so that all 8 were descended from one or the other or
both. ... From a study of the extended
CKCS
family tree, we
conclude that the disease occurs as a result of repeated close breeding
between 1 or more key descendants, C, D, K, M, and S--themselves descended
from 2 dams, G and Z. All of the affected dogs born in the last 5 years are
descended from C, D, K, M, and S via known or suspected carriers through at
least 6 of 8 great-grandparents. ... Selection for coat color and the
avoidance of some lines because they carry certain diseases (eg, heart and
cataract disorders) have narrowed the
CKCS
gene pool. As a
result, descendants of C, D, K, M, and S dominate modern
CKCS
pedigrees, compared to 10 years ago. Occipital hypoplasia currently is so
common in the breed that it could be considered ''normal'' for a
CKCS
to have some degree of occipital hypoplasia, with SM and
hydrocephalus occurring in the most severely affected dogs. ... SM secondary
to occipital hypoplasia is most common in Blenheims and rubies, which are
recessive coat colors and must be bred from a more restricted gene pool.
Selection for color affected the natural history of the disease because some
of the champion dogs that are important ancestors for SM were popular for
their tendency to ''throw'' a certain color. Breeders of wholecolor
CKCSs
commented that 15 years ago, tricolors such as sire D and dam
C were introduced to the ruby lines in an attempt to widen the gene pool but
still deliver some whole colors. This event appears to have been important
in the history of SM by increasing the cohort of dogs with genes from both G
and Z. ... The disease appears to be more severe and have an earlier onset
with increased inbreeding, especially when breeding from affected dogs. The
family tree of idiopathic epilepsy (IE) appears to be a different subset of
the
CKCS
population, although some overlap was observed.
Idiopathic epilepsy is more frequent in lines originating from whole-color
dogs. Selection for coat color is believed to have influenced the
development of both occipital hypoplasia with secondary SM and IE. In
addition, breeding guidelines to reduce the incidence of mitral valve
disease have placed further pressures on the gene pool.
Caudal occipital malformation syndrome in dogs
.  Dewey CW,
Berg JM, Stefanacci JD, et al. Compend. Contin. Educ. Pract. Vet. November
2004;26(11):886-896. Quote: "Chiari type 1 malformation in humans is a
congenital abnormality of the caudal occipital bone, resulting in
overcrowding of the caudal fossa and compression at the level of the
cervicomedullary junction. Both direct bony compression and progressive
meningeal hypertrophy at the level of the posterior (dorsal)
cervicomedullary junction are believed to lead to abnormalities of
cerebrospinal fluid flow dynamics. Central nervous system dysfunction often
develops in patients with Chiari type 1 malformation, with a variety of
possible neurologic manifestations. A disorder similar to human Chiari type
1 malformation occurs in dogs, but characteristic disease features have not
been thoroughly described. Most of the literature pertaining to the canine
form of the disease is from the United Kingdom, and almost all affected dogs
have been
cavalier King Charles spaniels
. Most reports
describe patients with cervical myelopathy due to syringohydromyelia.
Forty
cavalier King Charles spaniels
from the United
Kingdom were recently described with Chiari type 1 malformations; these dogs
displayed a wide variety of neurologic presentations, including central
vestibular dysfunction, seizure activity, and cervical myelopathy. We have
reviewed 30 cases of canine Chiari type 1 malformations diagnosed via MRI at
our hospitals from 2001 to 2002. This article reviews the pathophysiology,
clinical features, available treatment options, and prognosis for canine
Chiari type 1 malformations. Aspects of the human disorder and information
from previously published canine cases are discussed. However, the focus is
on the 30 recently reviewed cases. Results of this study suggest that caudal
occipital malformation syndrome is relatively common in small-breed dogs and
has many clinical similarities to Chiari type 1 malformation in humans."
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2005
Hindbrain decompression in a dog with scoliosis associated with
syringomyelia
. Takagi S, Kadosawa T, Ohsaki T, Hoshino Y, Okumura M,
Fujinaga T.  JAVMA, 2005 Apr.; 226 (8).
Neurological diseases of the
Cavalier King Charles spaniel
Rusbridge, C. J.  Small Anim. Prac., June 2005, 46(6): 265-272.
Treatment of Caudal Occipital Malformation Syndrome in Dogs by
Foramen Magnum Decompression.
CW Dewey, JM Berg, G Barone, DJ Marino,
JD Stefanacci. J Vet Intern Med; May/June 2005;19(3) (ACVIM 23rd Ann. Vet.
Med. Forum Abstract Program: Abstract 71). Quote: "Caudal occipital
malformation syndrome (COMS) is the canine analog of human Chiari I
malformation. As with human Chiari I malformation, dogs with COMS can
display a variety of clinical signs; these include cerebellovestibular
dysfunction, myelopathy (usually cervical), and seizure activity. Foramen
magnum decompression (FMD) is usually performed for humans with symptomatic
Chiari I malformation; results are favorable, with better outcomes being
attained with early surgical intervention. The purpose of this study was to
describe clinical results of a FMD procedure in 16 dogs with COMS. Cases
were restricted to dogs with MRI evidence of COMS and no other neurologic
disorders. All dogs underwent a FMD procedure that included either meningeal
resection or marsupialization to the surrounding musculature. Fifteen of 16
dogs were receiving medical therapy for COMS prior to surgery. Breeds
included
Cavalier King Charles spaniel
(9), Maltese (2),
Yorkshire terrier (1), and Pomeranian (1). Mean age was 3.86 yrs.
Neuroanatomic localization included multifocal CNS dysfunction (7), isolated
cervical myelopathy (6), isolated cerebellovestibular dysfunction (2), and
L4-S1 myelopathy (1). All dogs with multifocal CNS signs had evidence of
both cerebellovestibular and cervical spinal cord disease. Other specific
abnormalities included cervical hyperesthesia (13), diminished menace
responses (7), positional strabismus (7), excessive scratching behavior (6),
torticollis (3), abnormal mentation (2), "fly-biting" episodes (2), head
tilt (2), chewing at the paws (2), excessive licking (1), eye rubbing (1),
and generalized seizures (1). Mean duration of clinical signs prior to
surgery was 32.19 wks (1-208 wks). Syringohydromyelia was evident on MRI in
15/16 dogs (93.75%). No intraoperative complications occurred. Postoperative
complications occurred in two dogs. One dog had worsening of a head tilt,
which resolved in three weeks. Another dog experienced neck pain after the
initial FMD (resolved in four wks), and was nonambulatory tetraparetic
following repeat FMD. Resolution of clinical signs occurred in seven dogs
(43.75%), and improvement occurred in six dogs (37.5%), for an overall
positive result of 81.25%. One dog did not improve, one dog worsened and was
euthanized, and one dog died nine days following repeat FMD (the
tetraparetic dog), due to a suspected ruptured viscus. Repeat surgery was
performed in 4 dogs (25%), due to constrictive scar tissue formation at the
original FMD site. Drugs were discontinued in all dogs with resolution of
signs. Four of the 6 improved dogs remained on medical therapy. Five of 6
dogs with scratching behavior prior to FMD continued to do so
postoperatively; two of these five dogs required medical therapy to control
scratching. Mean duration of signs prior to FMD was 3.8 wks for the resolved
group, and 78.08 wks for the improved group. Results suggest that FMD is
often an effective treatment for COMS, especially if performed early in the
disease course."
CSF flow abnormalities in caudal occipital malformation syndrome
PA March, CJ Abramson, M Smith, and J Murakami. J Vet Intern Med 2005;19:418
(ACVIM 23rd Annual Veterinary Medical Forum Abstract Program: Abstract 72).
Quote: "The pathogenic factors responsible for the progression of signs in
the caudal occipital malformation syndrome (COMS) are not well understood.
The development of secondary syringohydromyelia appears to coincide with the
onset of clinical neurologic deficits but the CSF flow abnormalities that
lead to syrinx formation have not been described in dogs with COMS. The
purpose of this study was to characterize and compare CSF flow dynamics in
normal dogs and in dogs with COMS using cine phase contrast MRI. Dogs with
COMS were grouped according to severity of syrinx formation. Cine flowMRI
imaging was performed in the mid-sagittal and axial planes using a 1.5 Tesla
MR scanner (GE Medical Systems®) equipped with a retrospectively graded
phase contrast sequence to measure CSF flow velocity throughout the cardiac
cycle. Velocity encoding was cranial to caudal. Sixteen image frames per
cardiac cycle were evaluated for cranial and caudal flow velocities using a
GE Medical Systems® software program. Regions of interest were drawn
manually to encompass specific areas of subarachnoid space, syrinx cavities,
and cord parenchyma. CSF velocities, ratios of diastolic to systolic flow
times, and parenchymal movements were measured. Cine flow MRI was
successfully performed on 30 dogs. Flow determinations in the axial plane
were more reproducible and reliable than those in the mid-sagittal plane.
Axial and sagittal flow was significantly impaired in the region of the
cisterna magna and foramen magnum in dogs with COMS compared to normal dogs.
In severely affected dogs, reversal of CSF flow was observed during
diastole. Caudal movement of the caudal brainstem and cerebellum was
significantly greater and more prolonged in dogs with COMS. CSF flow in the
ventral subarachnoid compartment was minimally affected. Increased flow
gradients were found between more cranial and caudal dorsal subarachnoid
spaces in dogs with COMS. In the areas of syrinx formation, flow of CSF in
the dorsal subarachnoid space was less impaired but exhibited a longer
duration of caudal versus cranial flow. In dogs with moderate to severe
COMS, caudal and cranial CSF flow within the syrinx was marked and was equal
to flow velocities in adjacent subarachnoid spaces. This study demonstrated
that non-invasive cine flow MRI measurements can be performed in dogs and
that dogs with COMS have abnormalities of CSF flow and neural tissue shifts
during systole and diastole. Magnitudes of some of these changes were
correlated with the degree of syrinx formation. This imaging tool may be
useful in predicting progression of disease in dogs with COMS and further
studies are planned to investigate the role of cine flow MRI in monitoring
CSF flow dynamics before and after foramen magnum decompression surgery."
The Use of Ultrasonography to Diagnose "Caudal Occipital Malformation
Syndrome" in Dogs - a Prospective Study in 12 Dogs
. B Levitin, JJ
McDonnell, D Faissler, AS Tidwell. J Vet Intern Med; May/June 2005;19(3)
(ACVIM 23rd Ann. Vet. Med. Forum Abstract Program: Abstract 209).
Inherited Occipital Hypoplasia/Syringomyelia in the
Cavalier King
Charles Spaniel
: Experiences in Setting Up a Worldwide DNA Collection
Rusbridge C., Knowler P., Rouleau G. A., Minassian B. A., and Rothuizen J.
J.Heredity, Jun 2005; 10:1093.
Surgical Management of Combined Hydrocephalus, Syringohydromyelia,
and Ventricular Cyst in a Dog.
Hasegawa T., Taura Y., Kido H.,
Shibazaki, and Katamoto H. J. Am. Anim. Hosp. Assoc., July/August 2005; 41:
267 - 272.
Foramen magnum decompression for treatment of caudal occipital
malformation syndrome in dogs
. Dewey C.W., Berg J.M., Barone G., Marino
D.J., and Stefanacci J.D.  JAVMA, Oct. 2005 ; 227 (8): 1270-1275.
RETURN TO TOP
2006
Syringomyelia and genetic challenges [in
Cavalier King Charles
Spaniels
.  Dunn, T.J., Jr. Dog World, Apr. 2006; 91(4): 14-15.
Bakre skallgropens form hos hund: en studie av occipital hypoplasi
hos hund
. Spångberg, Camilla. Dept. of Small Animal Clinical Sciences,
Swedish University of Agricultural Sciences. Examensarbete (Sveriges
lantbruksuniversitet, Fakulteten for veterinarmedicin och husdjursvetenskap,
Veterinarprogrammet) vol. 2006:51. Quote: "The aim of the study was to
examine whether there is a difference in the shape of the caudal fossa
between
CKCS
, small bred dogs with a similar head shape and
dogs with a normal head shape and if occipital bone hypoplasia is related to
a head shape with a steep back of the head. Other aims of the study were to
examine the crowding of nervous tissue in the foramen magnum in each breed
group, the extent of syringohydromyelia and to what extent the malformation
had caused neurological signs. ... This study showed that there is a
difference in the shape of the caudal fossa between dogs with a normal head
shape and small bred dogs with a steep back of the head. This indicates that
occipital bone hypoplasia is related to a head shape where the back of the
head is steep and that the malformation is common in these breeds. The study
also showed that occipital bone hypoplasia not inevitably causes
syringohydromyelia. Only one of the dogs with occipital bone hypoplasia or
possible bone hypoplasia had had neurological signs that with certainty were
related to the malformation. This result gives further support to previous
studies that have stated that occipital bone hypoplasia occurs
asymptomatic." http://exepsilon.slu.se/archive/00000866/
Syringomyelia: Current Concepts in Pathogenesis, Diagnosis, and
Treatment.
Clare Rusbridge, Dan Greitz, and Bermans J. Iskandar. J Vet
Intern Med; May/June 2006;20(3):469-479. Quote: "Syringomyelia is a
condition that results in fluid-containing cavities within the parenchyma of
the spinal cord as a consequence of altered cerebrospinal fluid dynamics.
This review discusses the history and the classification of the disorder,
the current theories of pathogenesis, and the advanced imaging modalities
used in the diagnosis. The intramedullary pulse pressure theory (a new
pathophysiologic concept of syringomyelia) also is presented. In addition,
the current understanding of the painful nature of this condition is
discussed and the current trends in medical and surgical management are
reviewed."
Morphology of the Caudal Fossa in
Cavalier King Charles Spaniels
. S Cerda-Gonzalez,
NJ Olby, TP Pease,S McCullough, N Massoud, R Broadstone. J Vet Intern Med;
May/June 2006;20(3) (ACVIM 24th Ann. Vet. Med. Forum Abstract Program:
Abstract 95); Vet. Radiology & Ultrasound, Jan/Feb 2009;50(1):37-46.
Characteristics of Cerebrospinal Fluid Flow in
Cavalier King Charles
Spaniels
. S Cerda-Gonzalez, NJ Olby, TP Pease,S McCullough, N Massoud,
R Broadstone. J Vet Intern Med; May/June 2006;20 (ACVIM 24th Ann. Vet. Med.
Forum Abstract Program: Abstract 96).
Foramen Magnum Decompression with Cranioplasty for Treatment of
Caudal Occipital Malformation Syndrome in Dogs
. CW Dewey, KS Bailey, DJ
Marino, G Barone, P Bolognese, TH Milhorat, DJ Poppe. J Vet Intern Med;
May/June 2006;20(3) (ACVIM 24th Ann. Vet. Med. Forum Abstract Program:
Abstract 267).
Brain Stem Auditory Evoked Response (BAER) Testing in
Cavalier King
Charles Spaniels
with Caudal Occipital Malformation Syndrome
. CW Dewey,
KS Bailey, G Barone, J Stefanacci. J Vet Intern Med; May/June 2006;20(3)
(ACVIM 24th Ann. Vet. Med. Forum Abstract Program: Abstract 270).
Intracranial Epidermoid Cyst and Syringohydromyelia in a Dog
Edward Mackillop, Scott J. Schatzberg, Alexander De Lahunta. Vet. Rad. &
Ultra. July-Aug. 2006; 47:339.
Syringomyelia in
Cavaliers
. Bruce Fogle. Dogs Today, Aug 2006,
pg. 56.
Association Between Spinal Cord Dorsal
Involvement and Pain in
Syringomyelia Secondary to Canine Chiari Malformation
. C Rusbridge. H.
Caruthers, Marie-Pierre Dube´, M Holmes, N.D. Jeffery. 2006 ESVN Symposium,
Abstract #13. J.Vet.Intern.Med. 21(5). Quote: "This study was designed to
test the hypothesis that pain associated with syringomyelia in dogs is
related to spinal cord dorsal horn damage. Syrinx dimensions and precise
location within the spinal cord were determined by masked observers from
magnetic resonance images of
55 cavalier King Charles spaniels
(CKCS)
with syringomyelia. After removal of masking, syrinx
parameters were compared between the cohort of dogs that exhibited pain with
those that did not. Maximum syrinx width was the strongest predictor of pain
in dogs with syringomyelia. Syrinx width was also correlated with scratching
behaviour and scoliosis. Syrinx width was strongly correlated with dorsal
horn involvement. Dogs with pain were also more likely to have extensive
dorsal grey column damage. Large syrinxes with dorsal horn damage are
associated with persistent pain which may have implications for the success
of surgical and medical management. Our results suggest that the pain
behaviour expressed by this group of patients is likely to be 'neuropathic
pain', resulting from disordered neural processing in the damaged dorsal
horn. As such it is likely that conventional analgesic medication may be
ineffective."
Coexistence of occipital dysplasia
and occipital hypoplasia/syringomyelia
in the
cavalier King Charles spaniel
C. Rusbridge and S. P. Knowler.
J. Small Anim. Prac. Oct. 2006, 47(10):603-606. Quote: "Concurrent occurrence of
occipital dysplasia and occipital hypoplasia in two dogs is described in
this report. Occipital hypoplasia results in reduced volume of the caudal
fossa, leading to overcrowding of the neural structures and, in severe
cases, development of syringomyelia. In occipital dysplasia, there is a
failure of complete ossification of the supraoccipital bone. When the two
conditions occur concurrently, it is possible that syringomyelia may develop
more slowly, resulting in presentation with clinical signs in middle to old
age. This has implications for screening tests for early detection of
syringomyelia, with a view to using the dog for breeding purposes, as dogs
with an apparently mild phenotype for occipital hypoplasia/syringomyelia may
actually have a more severe genotype. ...  [On
post-mortem examination of CKCS and other small breed dogs that the
supraoccipital bone overlying the cerebellar vermis is remarkably thin and
sometimes eroded so that the foramen magnum is enlarged dorsally]."
RETURN TO TOP
2007
Chiari-like malformation and Syringomyelia in the
Cavalier King
Charles Spaniel
. Clare Rusbridge. PhD. thesis. Utrecht University,
Utrecht, The Netherlands. 2007.
New name agreed as international attention focuses on syringomyelia
Clare Rusbridge. Veterinary Times. Apr. 2007.
Association between
frontal-sinus size and syringohydromyelia in
small-breed dogs
. Peter V. Scrivani, Margret S. Thompson, Kevin R.
Winegardner, Curtis W. Dewey, Janet M. Scarlett. Am. J. Vet. Research, June
2007, Vol. 68, No. 6, Pages 610-613. Quote: "Our data do suggest, however,
that the pathogenesis of syringohydromyelia in small-breed dogs may involve
the supratentorial portion of the cranial cavity. We postulate that
syringohydromyelia develops in many small-breed dogs and certain breeds in
particular as a result of global malformation of the entire cranial cavity
or supratentorial portion of the cavity and is not limited to the
infratentorial portion of the cranial cavity. If this is true and results
can be generalized to the target population, our understanding of the
pathogenesis of syringohydromyelia in small-breed dogs and several aspects
of clinical management (e.g., screening and diagnostic testing, breeding
recommendations for dogs with dome-shaped heads, and treatments) will
require further investigation."
Chiari-Like Malformation with Syringomyelia in the
Cavalier King
Charles Spaniel
: Long-Term Outcome After Surgical Management.
Clare Rusbridge. Veterinary Surgery 2007 Jul;36(5):396-405. "Cranial
cervical decompression surgery is associated with low mortality
and morbidity, and results in clinical improvement in most dogs. The
procedure seemingly does not result in syrinx collapse and resolution.
Clinical improvement may not be sustained and some dogs can be expected to
deteriorate."
Report from the Chiari-Like Malformation and Syringomyelia Working
Group Round Table
. Rodolfo Cappello, organizer, Clare Rusbridge,
chairman. Veterinary Surgery 2007 Jul;36 (5), 509-512.
Foramen Magnum Decompression
with Cranioplasty for Treatment of
Caudal Occipital Malformation Syndrome in Dogs
. Curtis W. Dewey,
Dominic J. Marino, Kerry S. Bailey, Catherine A. Loughin, Georgina Barone,
Paolo Bolognese, Thomas H. Milhorat, Dorothy J. Poppe. Veterinary Surgery
2007 Jul;36
(5), 406-415. "Foramen Magnum Decompression (FMD) with cranioplasty was well
tolerated, with no intraoperative complications, and minor postoperative
complications. Most dogs improved clinically, and none required further
surgery at the original FMD site."
It's Time.
Richard A. LeCouteur. Veterinary Surgery
2007 Jul;36 (5),
390-395. "Medical history is replete with examples of invasive procedures
and pharmacologic interventions that were widely accepted based on results
of case studies, only to later be rejected based on results of controlled
clinical trials. ... It's time to adopt a more structured scientific
approach to the study of the management of neurologic conditions that may
benefit from surgical intervention. The randomized (preferably)
double-blinded (preferably) placebo-controlled study is the gold standard
for evaluating a new treatment intervention."
Syringomyelia in
cavalier
King Charles spaniels
: the relationship
between syrinx dimensions and pain.
C Rusbridge, H Carruthers, M-P Dube,
M Holmes, N D Jeffery. J Small Anim. Pract. 2007 Aug;48(8):432-6. Quote:
"Objectives: This study was designed to test the hypothesis that pain
associated with syringomyelia in dogs is dependent upon size and involvement
of the dorsal part of the spinal cord. Methods: Masked observers determined
syrinx dimensions and precise location within the spinal cord on magnetic
resonance images of 55 c
avalier King Charles spaniels
with
syringomyelia. After removal of masking, syrinx size and location were
compared between the cohorts of dogs that exhibited pain with those that did
not. Results: Maximum syrinx width was the strongest predictor of pain,
scratching behaviour and scoliosis in dogs with syringomyelia. Both pain and
syrinx size were positively correlated with syrinxes located in the dorsal
half of the spinal cord. Clinical Significance: Large syrinxes associated
with damage to the dorsal part of the spinal cord are associated with
persistent pain suggesting that the pain behaviour expressed by this group
of patients is likely to be 'neuropathic pain', resulting from disordered
neural processing in the damaged dorsal horn. As such it is likely that
conventional analgesic medication may be ineffective."
RETURN TO TOP
2008
Amantadine in a multimodal analgesic regimen for alleviation of refractory
osteoarthritis pain in dogs
. B.D.X. Lascelles, J.S. Gaynor, E.S.
Smith, S.C. Roe, D.J. Marcellin-Little, G. Davidson, E. Boland, J. Carr. J.
Vet. Intern. Med. January 2008;22(1):53-59. Quote: Background: Nonsteroidal
anti-inflammatory drugs (NSAIDs) do not always provide sufficient pain
relief in dogs with osteoarthritis (OA). Hypothesis: The use of amantadine
in addition to NSAID therapy will provide improved pain relief when compared
with the use of nonsteroidal analgesics alone in naturally occurring OA in
dogs. Animals: Thirty-one client-owned dogs with pelvic limb lameness
despite the administration of an NSAID. Methods: The study was randomized,
blinded, and placebo controlled with parallel groups (days 21-42). On day 0,
analgesic medications were discontinued. On day 7, all dogs received
meloxicam for 5 weeks. On day 21, all dogs received amantadine (3-5 mg/kg
once daily per os) or placebo for 21 days, in addition to receiving
meloxicam. Assessments were performed before the study and on days 7, 21,
and 42. Primary outcome measures were blinded owner assessments of activity
using client-specific outcome measures (CSOM) on days 0, 7, 21, and 42. Data
were analyzed by a mixed model approach. Results: For CSOM activity, there
was a significant time by treatment effect (P 5.009). On the basis of the
planned post hoc t-tests of postrandomization means, there was a significant
difference between treatment groups on day 42 (P 5.030), with the amantadine
group being more active. Conclusions and Clinical Importance: In dogs with
osteoarthritic pain refractory to an NSAID, physical activity is improved by
the addition of amantadine. Amantadine might be a useful adjunct therapy for
the clinical management of canine osteoarthritic pain.
Radiographic morphology
of the cranial portion of the cervical
vertebral column in
Cavalier King Charles Spaniels
and its relationship to
syringomyelia
. Catherine E. Stalin, Clare Rusbridge, Nicolas Granger,
and Nick D. Jeffery.. Am J Vet Res. 2008 Jan;69(1): 89-93. Quote: "Results
suggested that radiographic morphology of the atlantoaxial region in
CKCSs
differs from morphology of that region in dogs of other breeds, but that
these differences do not account for why some
CKCSs
develop syringomyelia
and others do not."
Pathophysiology and treatment
of neuropathic pain associated with
syringomyelia.
Clare Rusbridge and Nick D. Jeffery.  Vet. J. 2008
Feb; 175(2): 164-172. Quote: "The pain behaviour expressed by dogs with
syringomyelia suggests that they experience neuropathic pain, probably due
to disordered neural processing in the damaged dorsal horn. As such it is
likely that conventional analgesic medication will be ineffective. In this
review, physiological and pathological pain processing through the dorsal
horn is summarised and mechanisms by which syringomyelia could result in a
persistent pain state are discussed. Finally, current knowledge regarding
treatment of Chiari malformation and syringomyelia is reviewed and possible
drugs which may give improved pain relief in affected dogs are discussed."
A Practical Guide to Canine and
Feline Neurology
. Curtis W. Dewey. John Wiley & Sons; 2008; 4-6,129.
Quotes: ""Breed-associated neurologic abnormalities of dogs and cats. ...
Cavalier King Charles Spaniels
... Caudal occipital
malformation syndrome (with syringohydromyelia) " pp. 4-6. ""Caudal
occipital malformation syndrome is the canine analog of Chiari type I
malformation of people. Although only recently described in dogs, COMS
appears to be a very common neurologic disorder in this species. This
disease is almost exclusive to small breed dogs, with the
Cavalier
King Charles Spaniel (CKCS)
being the most overrepresented." p.
129.
Treatment of canine Chiari-like malformation and syringomyelia
. Dewey,
C., Rusbridge, C. In: Kirk's Current Veterinary Therapy XIV, 14th Ed. Bonagura,
J., Twedt, D. (Eds.),  Saunders, 2008 pp. 1102-1108.
Caudal Occipital Malformation Syndrome in
Cavalier King Charles
Spaniels
. C.W. Dewey. ACVIM 2008.
Ultrasonographic Appearance
of the Craniocervical Junction in Normal Brachycephalic Dogs and Dogs with
Caudal Occipital (Chiari-like) Malformation
. Martin J. Schmidt, Antje
Wigger, Sebastian Jawinski, Tanja Golla, Martin Kramer. Vet. Radiology &
Ultrasound. Aug 2008; 49(5): 472 - 476. Quote: "Ultrasonographic evaluation
of the spine, especially of the spinal cord, has been rarely reported in
dogs. The atlanto-occipital junction provides a small acoustic window
through which examination of the craniocervical transition can be performed.
Normal sonographic findings of this region in 10 normal brachycephalic dogs
are presented and compared with sonographic findings from 25
Cavalier King
Charles Spaniels
with the caudal occipital malformation syndrome. Sonographic findings were compared with magnetic resonance imaging findings
to determine the extent of cerebellar herniation and syringohydromyelia.
Cerebellar displacement into the foramen magnum was clearly identified
sonographically; however, syringohydromyelia was not discernable due to bone
overlay."
Chiari-like malformation and syringomyelia in normal
cavalier
King
Charles spaniels
: a multiple diagnostic imaging approach.
J. Couturier,
D. Rault, L. Cauzinille. J Small Anim. Pract. 2008 Sept;
49(9):438-443.  Quote: "Results: Of the 16 [
CKCS
] dogs in the study, 7
had syringomyelia (43.7%). All dogs had cerebellar herniation, suggesting
Chiari-like malformation and also a tendency to occipital dysplasia.
Computed tomography measurements of the caudal fossa are reported. In one
dog, a syrinx was identified by ultrasonography. The only difference between
dogs with or without syringomyelia was that dogs with Chiari-like
malformation/syringomyelia were statistically older. Clinical Significance:
The incidence of Chiari-like malformation and syringomyelia may be high in
an asymptomatic population of
cavalier King Charles spaniel
. Computed
tomography measurements reported in this study should now be compared with
those of a symptomatic population to evaluate the hypothesis that dogs with Chiari-like malformation/syringomyelia syndrome have a smaller caudal fossa.
This study did not identify a smaller caudal fossa in an asymptomatic
cavalier King Charles spaniel
population with syringomyelia. Ultrasonography
probably has a low sensitivity for diagnosis of Chiari-like
malformation/syringomyelia."
Intermittent "greeting"
due to Chiari-like
malformation/syringomyelia (CM/SM) and occipital dysplasia in a
Cavalier King Charles Spaniel
. Balthen-Nothen, A., Bull, C.,
Fehr, M., Fork, M., Tipold, A. Tieraerztliche Praxis Ausgabe Kleintiere
Heimtiere 2008; 36(2):119-125. Quote: "A 5.5-year-old male
Cavalier
King Charles Spaniel (CKCS)
was presented with an intermittent gait
abnormality of one front limb. During these episodes the dog flexed one
front limb for some minutes like a kind of 'greeting'. Between these
episodes the dog's gait was normal. Neurological examination the
neuroanatomical localization was considered to be primarily in the upper
motor neuron of the cervical spine. As a diagnostic imaging tool, a magnetic
resonance imaging (MRI) of the brain, cervical and thoracic spinal cord was
performed and the area of the foramen magnum was shown by computed
tomography. Results: In this patient a moderate herniation of the cerebellum
and severe syringohydromyelia of the cervical and thoracic spinal cord (Chiari-like
malformation and syringomyelia; CM/SM) was diagnosed. The foramen magnum was
dorsally widened in a keyhole shape. As therapy of the syringohydromyelia a
dorsal laminectomy at the level of the first cervical vertebra with
fenestration of the dura mater was performed. Up to a post surgery follow-up
eight weeks later, the dog no longer showed 'greeting', although in a
repeated MRI the dimensions of the syrinx still remained. Conclusion: Many
neurologic signs are described in association with a syrinx. This is the
first case report of a
CKCS
presenting intermittent
'greeting'. Furthermore the dog showed a combination of two anomalies:
Chiari-like malformation and syringomyelia (CM/SM) and occipital dysplasia.
Clinical relevance: It is recommended that the
CKCS
should
be screened for breeding purposes not only for occipital hypoplasia but also
for occipital dysplasia. A surgical decompression of the cerebrospinal
fluid-filled space can result in resolution of clinical signs, whereas MRI
failed to demonstrate an improvement of the syrinx. Further studies with
advanced MRI techniques would be necessary in the future to diagnose
morphologic as well as functional options of the cerebrospinal fluid-filled
space and -flow."
RETURN TO TOP
2009
Morphology of the
Caudal
Fossa in
Cavalier King Charles Spaniels
Sofia Cerda-Gonzalez, Natasha J. Olby, Susan McCullough, Anthony P. Pease,
Richard Broadstone, Jason A. Osborne. Vet. Radiology &
Ultrasound, Jan/Feb 2009;50(1):37-46.  Quote: "Chiari
malformations and syringohydromyelia are an important disease complex in
Cavalier King Charles
Spaniels
. Although
abnormalities in caudal fossa morphology are considered major contributors
to the development of this disease, limited information exists on the range
of morphologies in
Cavalier King Charles Spaniels
and on
the relationship of these to clinically evident disease. Sixty-four
Cavalier King Charles Spaniels
were studied. Each underwent a
neurologic examination and magnetic resonance imaging of the cervical spine
and brain. T2-weighted sagittal images were used to determine both the
morphologic characteristics and volume of the caudal fossa in each dog. This
volume was also analyzed as a percentage of total cranial cavity volume.
Each attribute was correlated with neurological grade and presence of
syringohydromyelia. Fifteen dogs had neurologic signs, and 59 had
morphologic abnormalities of the craniocervical junction. While 27 dogs had
syringohydromyelia, 13 of these were clinically normal. Cerebellar
herniation and occipital dysplasia were common findings but were not
associated with syringohydromyelia. Dorsal compressive lesions were noted at
the first and second cervical vertebral junction. Factors associated with
the presence of neurologic signs included syringohydromyelia and the ratio
of caudal fossa/total cranial cavity volume; dogs with signs had
significantly larger syringohydromyelia than asymptomatic dogs. Caudal fossa
size was not associated with syringohydromyelia. A positive association was
identified between foramen magnum size and length of cerebellar herniation.
The prevalence of craniocervical junction abnormalities is high in
Cavalier King Charles Spaniels
. While several factors are
associated with neurologic signs, occipital hypoplasia appears to be the
most important factor."
Clinical diagnosis and treatment of suspected neuropathic pain in three dogs
RG Cashmore, TR Harcourt-Brown, PM Freeman, ND Jeffery, N Granger.
Australian Vet. J. January 2009;87(1&2):45-50. Quote: Three dogs were
referred to The Queen's Veterinary School Hospital at University of
Cambridge for chronic behavioural or locomotor disorders associated with
pain. All three had been unsuccessfully treated with conventional
analgesics, including non-steroidal anti-inflammatory drugs, glucocorticoids
and opiate agonists, prior to referral, with minimal or no response. They
were investigated by neurological examination plus conventional ancillary
diagnostic tests and therapeutic drug trials. Ruling out other causes of
pain and applying previously well-described criteria, each case was
diagnosed as consistent with neuropathic pain, a poorly recognised condition
in domestic dogs. ... Apparent allodynia and dysaesthesia have been reported
in
Cavalier King Charles Spaniels
suffering from
Chiari-like malformation with syringomyelia. These animals often dislike
contact of the skin on their necks and typically exhibit 'phantom'
scratching, which are consistent with allodynia and dysaesthesia,
respectively. Apparent mechanoallodynia, hyperalgesia, and dysaesthesia were
prominent clinical features observed in all three dogs in this report. ...
Treatment with the tricyclic antidepressant drug, amitriptyline, or the
antiepileptic drug, gabapentin, resulted in either a dramatic improvement or
full resolution of clinical signs in all cases.
Use of
magnetic resonance imaging
for morphometric analysis of the caudal
cranial fossa in
Cavalier King Charles Spaniels
Carrera I, Dennis R, Mellor DJ, Penderis J, Sullivan M. Am J Vet Res; 2009
Mar;70(3):340-5. Quote: "Objective-To perform morphometric analysis of the
caudal cranial fossa in
Cavalier King Charles Spaniels (CKCSs)
to assess the relationship between caudal fossa dimensions and the frequency
of magnetic resonance imaging (MRI) features of occipital abnormalities in
CKCSs
(with and without syringomyelia), and to compare
caudal cranial fossa measurements in
CKCSs
with
measurements of 2 groups of mesaticephalic dogs. Animals-
70 CKCSs
and 80 mesaticephalic (control) dogs. Procedures-Dogs were placed into 4
groups as follows: Labrador Retrievers (n = 40), spaniel-type dogs (40;
English Springer Spaniels and Cocker Spaniels),
CKCSs with
syringomyelia (55), and CKCSs without syringomyelia (15)
. Multiple
morphometric measurements (linear, angular, and area) were obtained from
cranial midsagittalT2-weighted magnetic resonance images including the brain
and cervical portion of the spinal cord. Several specific MRI findings were
also recorded for
CKCSs
that appeared to affect the
occipital bone and cervicomedullary junction. Results-No significant
difference was identified among breeds in control groups and between sexes
in any of the groups for all morphometric measurements. Significant
differences were identified in
CKCSs
, compared with
mesaticephalic dogs, in the area of the caudal cranial fossa and for several
linear measurements that reflected the length of the ventral aspect of the
occipital bone. These differences were greater in
CKCSs
with syringomyelia. All
CKCSs
had abnormalities in
occipital bone shape. Conclusions and Clinical Relevance-
CKCSs
had a shallower caudal cranial fossa and abnormalities of the occipital
bone, compared with those of mesaticephalic dogs. These changes were more
severe in
CKCSs
with syringomyelia."
Evaluation of the
volumes of cranial cavities
in
Cavalier King Charles Spaniels
with Chiari-like malformation and other brachycephalic dogs as measured via
computed tomography
. Schmidt MJ, Biel M, Klumpp S, Schneider M, Kramer
M. Am J Vet Res. 2009 Apr;70(4):508-12. Quote: "Objective-To measure the
absolute and relative volumes of cranial vaults of
Cavalier King
Charles Spaniels (CKCSs
) and other brachycephalic dogs for the
purpose of evaluating a possible association between the volume of the
caudal fossa (fossa caudalis cerebri; CF) and existence of Chiari-like

malformation (CLM) and syringohydromyelia in
CKCSs
Animals-
40 CKCSs
and 25 brachycephalic dogs. Procedures-The
intracranial vault of all dogs was evaluated via computed tomography
followed by magnetic resonance imaging. Volumes of the CF and the rostral
and medial fossa (fossa rostralis et medialis cerebri) were determined. The
ratio of the absolute volumes was calculated as the volume index (VI).
Results-All
CKCSs
had cranial characteristics consistent
with CLM. There were no significant differences between
CKCSs
and brachycephalic dogs with respect to the VI and absolute volumes of the
CF and rostral and medial fossas. The
CKCSs
without
syringohydromyelia (n = 26) had a median VI of 0.1842, and
CKCSs
with syringohydromyelia (14) had a median VI of 0.1805. The median VI of
other brachycephalic dogs was 0.1864. The VI did not differ among these 3
groups. Conclusions and Clinical Relevance-Results of this study suggested
that descent of the cerebellum into the foramen magnum and the presence of
syringohydromyelia in
CKCSs
are not necessarily associated
with a volume reduction in the CF of the skull."
Imaging features of atlanto-occipital overlapping in dogs
Cerda-Gonzalez S, Dewey CW, Scrivani PV, Kline KL. Vet. Radiology
Ultrasound. May 2009;50(3):264-268. Quote: "The imaging features of four
dogs with atlanto-occipital overlapping are described. This malformation
appeared to play a role in the development of neck pain, ataxia, variable
cerebellar involvement, medullary kinking, and possibly syringomyelia. Using
cervical radiographs, three of the four dogs were initially diagnosed with
an atlanto-axial malformation. Because this disorder could not account for
all clinical signs, magnetic resonance and computed tomography images were
also acquired. These provided a more complete evaluation of the
craniocervical junction, allowing detection of atlanto-occipital
overlapping, medullary kinking, occipital dysplasia, abnormalities of the
dens, and syringomyelia in these dogs. Head position during imaging affected
the degree of atlanto-occipital overlap. These findings emphasize the need
to modify the currently accepted imaging recommendations for dogs with head
and neck pain and/or cranial cervical myelopathy. We suggest that the entire
craniocervical junction be evaluated, even if atlanto-axial subluxation has
already been detected. Moreover, we propose that atlanto-occipital
overlapping is a perhaps underrecognized disorder that can influence the
clinical signs and therapeutic outcome of dogs with anomalies of the
craniocervical junction."
Muscular
dystrophy in
Cavalier King Charles spaniels
Piercy, Richard. J. and Walmsley, Gemma. Vet Rec. 2009 165 (2), p. 62.
Quote: "We have recently identified the genetic cause of a form of muscular
dystrophy in
CKCS
. The causative mutation is in the
dystrophin gene and the X-linked disease is associated with weakness, muscle
atrophy and exercise intolerance, detectable from a few months of age.
Prominent signs in affected dogs are dysphagia [the symptom of difficulty in
swallowing] and macroglossia (enlarged tongue)[tongue enlargement that leads
to functional and cosmetic problems]. Serum creatine kinase is usually
markedly elevated. Male dogs with the mutation [are] clinically affected and
female dogs with the mutation are silent carriers. We are also keen to hear
from veterinary surgeons who believe they may have seen an affected dog in
their practice, in order to estimate the prevalence of this disease and
limit its spread by genetic testing."  Contact Dr. Piercy at the Royal
Veterinary College's Comparative Neuromuscular Diseases Laboratory at rpiercy@rvc.ac.uk
oes size matter? The continuing riddle of Chiari and
syringomyelia
. Simon R. Platt, Marc Kent, and Scott J. Schatzberg. J
Small Anim. Pract. 2009 Aug; 50(8):383-384.
Association between cervical and intracranial dimensions
and
syringomyelia in the
cavalier King Charles spaniel
. H.
Carruthers, C. Rusbridge, M.-P. Dube, M. Holmes, and N. Jeffery. J Small
Anim. Pract. 2009 Aug; 50(8):394-398. Quote: "Objectives: To investigate the
possible association between caudal fossa area and cervical vertebral
dimensions and the presence of syringomyelia in
cavalier King
Charles spaniels
. Methods: From magnetic resonance imaging scans of
78
cavalier King Charles spaniels
, measurements were made
of the widest vertical spinal width at C1/C2, C2, C2/C3 and C3; angulation
of the C2/C3 spine; and estimated caudal fossa area. A correlation between
these measurements and syringomyelia was sought. Results: A total of 59 dogs
with and 19 without syringomyelia were compared. Older dogs had a
significantly higher incidence of syringomyelia. No difference in incidence
was noted between genders. There was no significant difference in vertebral
canal width at C1/C2 and C2, or angulation of C2/C3 between syringomyelia
and non-syringomyelia groups. The width of the canal at C2/C3 and C3 was
significantly increased in syringomyelia dogs. There was no significant
difference in the caudal fossa area between groups. Clinical Significance:
Although syringomyelia was shown to be more prevalent in older dogs, the age
beyond which dogs were considered at greater risk was not deducible from the
dataset. The association identified between wider spinal canal at C3, and
C2/C3 and syringomyelia presence is of questionable clinical significance,
as the difference between syringomyelia and non-syringomyelia groups is too
small to be measured in a clinical setting."
Chiari-like malformation in the Griffon Bruxellois
. C. Rusbridge,
S. P. Knowler, L. Pieterse, and A. K. McFadyen. J Small Anim. Pract. 2009
Aug; 50(8):386-393.  Quote: "It should also be realised that although
this study found a method of predicting CM in the [Griffon Bruxellois], this
may not be transferable to other breeds. This may be especially true for the
CKCS
where CM is almost ubiquitous ... ."
Comparison of cerebral cranium volumes
between
cavalier King Charles
spaniels
with Chiari-like malformation, small breed dogs and Labradors.
H. R. Cross, R. Cappello, and C. Rusbridge.  J
Small Anim. Pract. 2009
Aug; 50(8):399-405  Quote: "Objectives: To ascertain whether
cavalier King Charles spaniels (CKCSs)
have a
proportionately smaller caudal fossa compared with other small dogs and with
Labradors.  ... Labradors were chosen as a
'control' group because their skull is relatively dolichocephalic and a
large database of MRI scans was available. ... To evaluate if cerebellar herniation in
CKCS
correlates with caudal fossa volume. Methods: In this retrospective study,
three-dimensional images were created from magnetic resonance imaging brain
series of 117 dogs (split into three groups:
CKCS
Labradors and small breeds) from which the volumes of the fossae and brain
parenchyma were calculated. These volumes were transformed into percentages
of total cranial cavity and parenchyma volumes, respectively. The
percentages were statistically compared among the groups. The percentage of
herniated cerebellum in the
CKCS
was compared using linear
regression with the caudal fossa and parenchyma percentages. Results: ...
When compared with Labradors,
CKCS
had proportionately the
same volume of parenchyma in their caudal fossa, hence there is a mismatch
of volumes with too much parenchyma in a too small caudal fossa causing
overcrowding. This supports either theory of pathogenesis of CM as mesoderm
insufficiency during embryology − causing insufficient scope for the
mesoderm and ectoderm layers to develop ... − or alternatively premature
growth plate closure. Other small breeds of dogs had a proportionately
smaller volume of parenchyma in their caudal fossa which can explain why,
despite having a similar sized caudal fossa to
CKCS
, they
do not experience overcrowding. It is hypothesised that through the
miniaturisation process of other small dogs, both the cranium and brain are
proportionately smaller but in
CKCS
only the cranium has
reduced in volume, hence why there is a higher incidence of CM in CKCS than
other small breeds.
Cavalier King Charles spaniels
also had
a greater percentage of their cranial fossa filled with parenchyma (cranial
fossa parenchyma percentage) compared with small breeds and Labradors which
had a similar percentage. Overcrowding in
CKCS
might
therefore occur due to a mismatch in volumes in both the caudal fossa and
cranial fossa of the skull, suggesting the cranial fossa is also involved in
the pathophysiology of CM. From this study, all
CKCS
are at
an increased risk of showing cerebellar distortion visible on MRI scans due
to caudal fossa overcrowding, but the volume measurements are unable to
predict cerebellar herniation which may be influenced by other skull
abnormalities like occipital dysplasia resulting in a wider FM ... .
Furthermore, RI scans of young
CKCS
may not help to predict
the development of SM in later life as a complication to CM. Therefore, it
is necessary for further studies to be conducted in order to investigate
correlations between cranium volumes and disease progression and clinical
signs."
Characteristics of Cerebrospinal Fluid Flow in
Cavalier King Charles Spaniels
Analyzed Using Phase Velocity Cine
Magnetic Resonance Imaging
Sofia Cerda-Gonzalez, Natasha J. Olby,
Richard Broadstone, Susan McCullough, Jason A. Osborne. Vet. Rad. &
Ultrasound, Sep/Oct 2009, 50(5):467-476. Quote: "Syringomyelia is an
important morbidity source in
Cavalier King Charles Spaniels.
Although abnormal cerebrospinal fluid (CSF) flow secondary to Chiari
malformations is thought to cause syringomyelia in humans, this relationship
is unknown in dogs. We used phase-contrast magnetic resonance (MR) imaging
to evaluate CSF flow in dogs. Fifty-nine
Cavalier King Charles
Spaniels
were assigned a neurologic grade reflecting their
neurologic status. Five normal control dogs of other breeding were imaged
for comparison. The presence of syringomyelia was noted from sagittal MR
images. The pattern and velocity of CSF flow were assessed using
phase-contrast cine MRI at the foramen magnum, C2-C3 disc space, and within
syrinxes. Flow was measured most easily with the neck flexed to mimic
standing. CSF flow velocity in the dorsal aspect of the subarachnoid space
at the foramen magnum was significantly higher in control dogs than
Cavalier King Charles Spaniels
. Flow was obstructed at
the foramen magnum in 41 of 59
Cavalier King Charles Spaniels
Turbulent flow and jets were associated with syringomyelia presence and
severity, and CSF flow velocity at C2/3 dorsally was inversely related to
the presence of syringomyelia. Peak dorsal subarachnoid space CSF
flow velocity at the foramen magnum and C2-C3 were together highly
predictive of syringomyelia. CSF flow can be assessed in dogs using
phase-contrast cine MRI. Obstruction to flow at the foramen magnum is common
in
Cavalier King Charles Spaniels
and CSF flow pattern and
velocity are related to the presence of syringomyelia."
Volumetric Analysis
Of Brain Parenchyma Within The
Caudal Fossae Of
Cavalier King Charles Spaniels
Driver, C Rusbridge, H Cross, HA Volk. 22nd ECVN Annual Symposium, Sept.
2009; J Vet Intern Med, Jan/Feb 2010;24(1):242. Quote: "Chiari-like
malformation (CM) and syringomyelia (SM) is a debilitating disease complex
recognized in the
Cavalier King Charles Spaniel (CKCS)
Mesoderm insufficiency during embryogenesis has been suggested as the
pathogenesis of Chiari type-I malformations in humans leading to a small
posterior fossa but a normally developed hindbrain. No volumetric evidence
exists regarding the role of hindbrain volume within the caudal fossa in the
development of SM in dogs. Magnetic resonance (MR) images of
59 CKCS
with CM and no other systemic disease were retrospectively reviewed. ...
Volumes of hindbrain parenchyma were analyzed as percentages of caudal fossa
volume and caudal fossa volume was analyzed as a percentage of total cranial
cavity volume. The volume of the ventricular system was recorded as a
percentage of total parenchymal volume. If SM was present, syrinx size was
measured from T2 weighted MR images from the maximal dorsoventral dimension
within the cervical spine. SM was present in 40/59 (68%) dogs. All data was
normally distributed. There was no significant (t-test, p=5 0·702) age
difference between dogs with (61.2 ± 33.8
months; 6.8-128.9) or without SM (57.4
37.1 months; 3.9-122.8). Caudal fossa percentage of the total cranial cavity
volume did not differ significantly (t-test, p=5 0·520) between dogs without
(14.4 ±
1.5%) or with (14.9 ±
1.3%) SM. However, there was a significant difference (p=50·002) between the
two groups looking at hindbrain parenchyma percentage of the caudal fossa
(86.7 ±
4.1% and 89.9 ±
1.67% respectively). Furthermore, in the SM group a significant positive
association was found between the hindbrain parenchyma percentage and syrinx
size (spearman r=5 0·437). No significant difference (p=5 0·164) was found
between the two groups for ventricular volume (5.30
7.68% and 7.73 ±
5.36% respectively), however when a syrinx was present a strong positive
correlation was found between ventricular and syrinx size (spearman r=5
0·500). This work supports recent evidence that caudal fossa size is not
associated with SM, but that overcrowding of the caudal fossa leads to SM
and may be caused by mesoderm insufficiency. The association between
ventricle and syrinx dimensions supports the theory that SM develops as a
result of altered CSF dynamics."
Anatomical Distribution of Syringomyelia in
Cavalier King Charles Spaniel
With Chiari.Like
Malformation
. S Loderstedt, L Benigni, K Chandler, C Lamb, C Rusbridge,
HA Volk. 22nd ESVN Annual Symposium, Sept. 2009; J Vet Intern Med, Jan/Feb
2010;24(1):253. Quote: "The objective of this study was to evaluate the
prevalence and anatomical distribution of syringomyelia
(SM) in clinically-affected
CKCS
. It was hypothesised that
(1) SM is not restricted to the cervical region of the spine, (2) the maximal syrinx
diameter can occur anywhere along the spinal cord, (3) there is an
association between cervical syrinx diameter and distribution and SM in
other regions of the spinal cord. Thirty-seven
CKCS
with
clinical evidence of SM were studied prospectively. Magnetic resonance (MR)
imaging of the brain and the entire spinal cord of each dog were performed
at 1.5 Tesla. ... SM was not limited to the cervical region. SM was present in the region of the C1-C4 vertebral bodies in
all dogs (100%) however it often was not limited to that area being also
found at C5- T1 in 31/37 (84%), T2-L2 in 29/37(78%) and L3-L6 in 21/37
(57%). Maximal SM diameter occurred at C1-C4 in 19/37 (51%) dogs, at C5- T1
in 2/37 (5%), at T2-L2 in 15/37 (41%) and at L3-L6 in 1/37(3%) dogs,
respectively. There was no significant difference between the mean syrinx
diameter at the region C1-C4, C5- T1 and T2-L2 but mean syrinx diameter was
less in the region L3-L6. Mean syrinx diameter at C1-C4 was positively
correlated with mean syrinx diameter at C5- T1, T2-L2 and L3-L6
respectively. Many
CKCS
with a cranial
cervical syrinx also have a syrinx affecting more caudal regions of the
spinal cord. Dogs with a large cranial cervical syrinx tend to also have a
large syrinx more caudal. MR imaging restricted to the cervical region will
underestimate the extent of the syrinx and the severity of the disease
process in the majority of dogs."
Surgical
Stabilization of a Craniocervical Junction Abnormality With
Atlanto-Occipital Overlapping in a Dog
. Curtis W. Dewey, Sofia
Cerda-Gonzalez, Peter V. Scrivani, Andrea. Looney, Gena M. Silver.
Compendium Vet. October 2009. E1-E6, Quote: "A 3-year-old male neutered
Pomeranian presented with severe, poorly localizable pain that was
unresponsive to a combination of oral medications (gabapentin, tramadol,
prednisone, and methocarbamol) and a fentanyl patch. A Chiari-like
malformation with associate syringomyelia was evident on magnetic resonance
imaging (MRI). In addition, overlapping of the dorsal arch of C1 and the
dorsal aspect of the foramen magnum was suspected from the MRI scans and
verified via computed tomography
(see image at right)
, suggesting a
condition similar to basilar invagination/impression in people. At surgery,
a combination of foramen magnum decompression with cranioplasty and
stabilization of the atlanto-occipital junction was performed. The
atlanto-occipital junction was stabilized using an adaptation of a procedure
used in people for basilar invagination/impression. Over the next several
months, the dog's clinical signs improved dramatically, allowing substantial
reduction of oral pain medications. This is the first report of surgical
stabilization for atlano-occipital overlapping in a dog."
Foramen Magnum Decompression with Free
Autogenous Adipose Tissue Graft
for Treatment of Caudal Occipital Malformation Syndrome in Dogs
. Erin
Y. Akin, Nora H. Ortinau, Andy Shores, M. B. Carnes, Jill Narak. 2009 ACVS
Vet. Symposium Abstract. Quote: "The objective of this study was to describe
and evaluate a modified surgical technique using foramen magnum
decompression (FMD), durotomy, duroplasty with swine intestinal submucosa
(SIS), and a free autogenous adipose tissue graft (FAATG) for the treatment
of canine caudal occipital malformation syndrome (COMS). Fourteen
client-owned dogs with MRI evidence of COMS and surgical treatment with FMD
were included in this 18-month prospective study (10/07 - 3/09). Breeds
treated included
Cavalier King Charles Spaniel
(11),
Chihuahua (2), and Pomeranian (1). Surgical decompression of the foramen
magnum and durotomy were performed in a fashion similar to previously
described techniques. ... The dura was marsupialized, suturing it to the
surrounding fascia using simple interrupted sutures of 5-0 polydioxanone
(fig 3). The SIS was sutured to the dura in a tent-like fashion using simple
interrupted sutures of 5-0 polydioxanone. The FAATG, typically obtained from
the gluteal region, was placed over the defect followed by a sheet of
gelatin foam. ... Overall, recovery was considered to be good to excellent
by owners. To date, none of the patients that have undergone this surgical
procedure have required further surgical intervention due to postoperative
compressive scar formation that has been reported in the previous
literature. ... In dogs that require FMD in the treatment of COMS, this
modified technique using a FAATG should be considered. Current clinical
outcomes of patients that were treated for COMS using this technique showed
excellent results similar to current published literature without intraoperative complications and clinical improvement with a decrease in
clinical signs postoperatively. The use of the titanium mesh, placement of
the screws, and the exothermic reaction of the overlying methyl methacrylate
may contribute to tissue trauma. The authors conclude that with the results
of this study, this procedure is clinically effective and the use of a
titanium mesh, additional hardware and methyl methacrylate offers no
advantage in canine COMS patients."
RETURN TO TOP
2010
Congenital Diseases of the Craniocervical Junction in the Dog
Sofia Cerda-Gonzalez, Curtis W. Dewey. Vet. Clinics: Small Animal Pract.
January 2010;40(1):121-141. Quote: "Craniocervical junction disorders are
most frequently seen in toy and small-breed dogs. They can present a
diagnostic challenge, as multiple anomalies can be present concurrently and
share similar clinical manifestations. Some, such as Chiari-like
malformations, may be present in asymptomatic dogs. A thorough evaluation of
the entire craniocervical junction, frequently using more than 1 imaging
modality, is necessary before making treatment decisions. ... The
craniocervical junction (also known as the craniovertebral junction)
consists of the occipital bone, foramen magnum, atlas, axis, and the
ligament of the atlantoaxial and atlantooccipital junctions. It functions as
a single unit to provide support and movement of the head in relation to the
body. The craniocervical junction is united by a single, continuous, joint
cavity, which includes the atlantooccipital and atlantoaxial junctions and a
fluid-filled cavity separating the dens and the body of the atlas. The
atlantooccipital junction is further stabilized by dorsal and ventral
atlantooccipital membranes, bilateral lateral atlantooccipital ligaments,
and ligaments extending from the body of the atlas to the foramen magnum.
This junction allows lateral and dorsoventral movement of the head in
relation to the cervical spine. The atlantoaxial junction, in turn, is
stabilized by the dorsal atlantoaxial ligament and the transverse atlantal
ligament. The apical and alar ligaments extend cranially from the dens to
the occiput, spanning the atlantoaxial and atlantooccipital junctions. The
atlantoaxial junction primarily permits rotational movement of the head. The
occipital bone is divided into 3 components: the supraoccipital bone, the
exocciput, and the basiocciput. The supraoccipital bone surrounds the
foramen magnum, the occipital conndyles arise from the exoccipital bone, and
the basiocciput forms the base of the skull."
Heritability of syringomyelia in
Cavalier King Charles
spaniels
Tom Lewis, Clare Rusbridge, Penny Knowler, Sarah Blott, John
A. Woolliams. Vet.J. 183(3): 345-347 Mar. 2010. Quote: "Mixed model analysis of 384
Cavalier King Charles spaniels (CKCS)
, with a magnetic
resonance imaging diagnosis for the presence or absence of a syrinx, in
conjunction with the Kennel Club pedigree records of all dogs registered
from the mid 1980s to September 2007, revealed a moderately high estimate of
heritability of syringomyelia (h2 = 0.37 ± 0.15 standard error) when
analysed as a binary trait. Inspection of cases where the disease segregated
within families pointed to genes at more than one locus influencing
syringomyelia. The availability of estimated breeding values for Kennel Club
registered
CKCS
is a significant step in being able to
select against syringomyelia, particularly given the difficulty of
ascertaining the disease phenotype."
Syringomyelia in the
Cavalier King Charles
spaniel (CKCS)
dog
. Katheryn C. Wolfe, Roberto Poma. Can Vet
J;51:95-102; Jan 2010. Quote: "Recent data suggest that CM in the
Cavalier King Charles spaniel (CKCS)
is inherited. The incidence of
CM in the
CKCS breed
is an estimated 95% and current
studies suggest that SM is present in more than 50% of dogs with CM with
approximately 35% of affected dogs exhibiting clinical signs. ... Overall,
the prognosis for CM/SM-affected dogs depends on the severity of clinical
signs and on the response to medication. Chiari-like malformation and
syringomyelia is a progressive condition in those dogs that are affected
clinically. Some dogs will need constant dose adjustments to adequately
treat their symptoms. Unfortunately, some dogs afflicted with severe and
disabling pain do not respond to medical management and are not surgical
candidates, in which cases a thorough evaluation of their quality of life is
necessary."
Optimisation of breeding strategies
to reduce the prevalence of
inherited disease in pedigree dogs.
Lewis, T.W.; Woolliams, J.A.; Blott,
S.C. Animal Welfare 19(Supp 1):93-98(6), May 2010. Quote: "One option for
improving the welfare of purebred dog breeds is to implement health breeding
programmes, which allow selection to be directed against known diseases
while controlling the rate of inbreeding to a minimal level in order to
maintain the long-term health of the breed. The aim of this study is to
evaluate the predicted impact of selection against disease in two breeds:
the
Cavalier King Charles spaniel (CKCS)
....
Heritabilities for mitral valve disease, syringomyelia in the
CKCS
... were estimated to be 0.64 (± 0.07), 0.32 (± 0.125) ... respectively,
which suggest encouraging selection responses are feasible based upon the
estimation of breeding values (EBVs) if monitoring schemes are maintained
for these breeds. Although using data from disease databases can introduce
problems due to bias, as a result of individuals and families with disease
usually being over-represented, the data presented is a step forward in
providing information on risk. EBVs will allow breeders to distinguish
between potential parents of high and low risk, after removing the influence
of life history events. Analysis of current population structure, including
numbers of dogs used for breeding, average kinship and average inbreeding
provides a basis from which to compare breeding strategies. Predictions can
then be made about the number of generations it will take to eradicate
disease, the number of affected individuals that will be born during the
course of selective breeding and the benefits that can be obtained by using
optimisation to constrain inbreeding to a pre-defined sustainable rate."
Genome wide linkage
studies identifies a novel locus
for syringomyelia associated with Chari-like malformation in the
Cavalier King Charles Spaniels
. Quoc-Huy Trink, Penny Knowler,
Alexandra Thibault, Marie-Pierre Dube, Guy A.
Rouleau, Clare Rusbridge, and Zoha Kibar. May 20, 2010.
Relationship of brain parenchyma
within the caudal cranial fossa and
ventricle size to syringomyelia in
cavalier King Charles spaniels
C. J. Driver, C. Rusbridge, H. R. Cross, I. McGonnell, and H. A. Volk. J
Small Anim. Pract.; July 2010; 51(7):382-386 Quote: "Objectives: To assess if the
volumes of the caudal cranial fossa (CCF), parenchyma within the caudal
cranial fossa (CCFP) or ventricles (V) are associated with syringomyelia
(SM) in
cavalier King Charles spaniels (CKCS)
with Chiari-like
malformation (CM). To evaluate if volumes are associated with transverse
syrinx width. Methods: Magnetic resonance images of 59
CKCS
with CM were retrospectively reviewed and grouped with or without SM.
Three-dimensional images were created and volumes of the fossae, brain
parenchyma and ventricular system were calculated from which percentages of
CCF, CCFP and V were created. If present, syrinx size was measured from its
maximal transverse width. The percentages were statistically compared
between groups, and correlation between percentages and syrinx dimensions
was made. Results:
CKCS
with SM had significantly higher
CCFP (P=0
·0001) and V (P=0·0002) to those without but no significant
difference in CCF (P=0·925). There was a positive correlation between CCFP
and syrinx width (Pearson r=0·437) and ventricle size to syrinx width
(Spearman r=0·627). Clinical Significance: A more marked overcrowding of the
CCF is associated with SM, which may explain the high incidence of SM in
CKCS
with CM. The association between ventricle and syrinx
dimensions supports the theory that SM development is the result of altered
cerebrospinal fluid dynamics."  See also:
Volumetric Analysis Of Brain Parenchyma Within The
Caudal Fossae Of
Cavalier King Charles Spaniels
above.
Canine
Chiari-like Malformation:
A Comparison of Ventricular and Caudal Fossa
Volumes in
Cavalier King Charles Spaniels
> 5 years of age
that have not developed Syringomyelia vs those Affected when < 2 years.
C Driver, C Rusbridge, HA Volk. Abstract at 2010 BSAVA conference.
MRIs of 21
Cavalier King Charles spaniels
under 2 years
affected with CM/SM, and 14 CKCSs over 5 years with only CM were analyzed.
Conclusion: Severe SM in
Cavaliers
under 2 years old is
associated with greater mis-match between hindbrain and caudal fossa volume
than found in older
CKCSs
with CM but no SM. They also
measured the dimensions of the brain's ventricle cavities of SM-affected
Cavaliers, and they found that the ventricle volumes had a direct
correlation with the width of the syrinx.
Transcranial
Magnetic Motor Evoked Potentials
, Somatosensory Evoked Potentials,
Spinal Evoked Potentials and Brainstem Auditory Evoked Potentials in
Cavalier King Charles Spaniel
Dogs with and Without Syringomyelia
K Wolfe, S Nykamp, DG Allen, J Armstrong, R Poma. J Vet Intern Med
2010;24:--- (ACVIM 28th Ann. Vet. Med. Forum Abstract Program: Abstract
231). Quote: "The aim of this study was to evaluate the validity of
transcranial magnetic motor evoked potentials (TMMEP), somatosensory evoked
potentials (SSEP), spinal evoked potentials (SEP) and brainstem auditory
evoked responses (BAER) in the assessment of motor and sensory pathways
throughout the central nervous system of
CKCS
dogs with and
without SM diagnosed by MRI. Fifty
CKCS
dogs were
evaluated. Neurologic deficits were graded 0-3 (0 5 normal, 1 5 cervical or
thoracolumbar pain on palpation, 2 5 cervical or thoracolumbar pain on
palpation plus evidence of neuropathic pain, 3 5 ataxia or paresis). TMMEP,
SSEP, SEP, and BAER were performed on all dogs under sedation with
hydromorphone (0.05 mg/kg IV) and acepromazine (0.025 mg/kg IV). Onset
latencies (msec) were measured for TMMEP, SSEP and SEP and IV interpeak
latencies were measured for BAER. Dogs were anesthetized for brain and
spinal cord MRI (cervical, thoracolumbar, lumbar) including sagittal and
transverse T2-weighted images. ... Based on neurologic score and MRI
findings, all dogs were classified into group A (n 5 16) (neurologic
abnormalities and MRI confirmed SM), B (n 5 9) (neurologic abnormalities and
no SM), C (n 5 11) (normal neurologic examination and MRI-confirmed SM), and
D (n 5 14) (normal neurologic examination and no SM). There were no
significant differences observed in the mean latencies of TMMEP, SSEP, SEP
and BAER between groups A, B, C and D. However, a significant linear
correlation was observed between the severity of neurologic dysfunction and
size of the syrinx (p 5 0.017; t-test procedure, SAS) with a larger syrinx
being associated with more severe neurologic signs.
In conclusion
TMMEP, SSEP, SEP and BAER do not appear to be valuable tests in detecting
functional abnormalities of the motor and sensory pathways throughout the
central nervous system of CKCS dogs with and without neurological signs
secondary to SM diagnosed by MRI."
Association between Chiari-like malformation and
syringomyelia in
cavalier King Charles spaniels
C. J. Driver, C. Rusbridge, H. R. Cross, I. McGonnell, and H. A. Volk. Vet Rec.,
Aug. 2010 167:306.
Breed Predispositions to Disease in Dogs & Cats (2d
Ed.)
. Alex Gough, Alison Thomas. 2010; Wiley-Blackwell Publ. 52.
Concurrent occipital hypoplasia, occipital dysplasia,
syringohydromyelia, and hydrocephalus in a Yorkshire terrier.
Laura
Cagle. Can Vet J. 2010 Aug.; 51(8): 904-908.
The Incidence
of Syringomyelia
in the
Cavalier King Charles Spaniel
J. E. Parker, S. P. Knowler, C. Rusbridge, T. J. McKinley, E. Noorman and N.
D. Jeffery. Abstract at 23d ECVN symposium, Sept. 2010. Quote: "The
epidemiology of cervical syringomyelia in a population of
804
Cavalier King Charles Spaniels (CKCS
) was investigated using the
results of a voluntary MRI screening programme that is ongoing in the United
Kingdom (UK) and the Netherlands. The aim of the study was to establish the
incidence of disease and to determine the risk factors for its development.
... The lifetime risk of developing syringomyelia in the study population
was estimated to be 55%. Of the variables investigated, only the age at
which a scan was performed significantly predicted the outcome of screening
and the likelihood of detecting the disease increased with age-at-scan up to
the age of four years. The predictive accuracy of the final model was 62.4%
and factors not evaluated by this study are therefore also likely to
contribute to the timing of disease manifestation. It is concluded that
syringomyelia is likely to be one of the most common disease conditions of
the
CKCS
. The age at which an MRI scan is performed
predicts the likelihood of disease detection and a susceptible individual
may not express the diagnostic phenotype until the age of four. Performing
screening before this time may give a false negative result for the lifetime
risk of disease development."
Interim Breeding
Guidelines -- 4 Year Report
. SP Knowler, AK McFadyen, C Rusbridge.
Abstract at 23d ECVN symposium, Sept. 2010. Quote: "...a cohort of 465 dogs
(307 females, 158 males) were identified which had either one (316 dogs) or
both parents (149 dogs) with MRI confirmed CMSM status. Of these,
393 were CKCS [cavalier King Charles spaniels]
and 72 were Griffon
Bruxellois. All dogs were assigned an A - F CMSC grade according to the
current breeding guidelines. Grade A implies a SM unaffected dog over 2.5
years old. In addition, to estimate the influence of late onset SM, an Grade
A* was assigned to Grade A dogs over 5 years old. The CMSM grade of all
offspring from all possible breeding combinations including using one parent
of unknown status (Grade U) was ascertained. Offsrping without SM only
occurred when there was at least one parent of Grade A status. There were
higher numbers of SM clear offspring if both parents had A status. In
addition all A* offspring also had at least one A* parent and higher numbers
of A* offspring resulted from crosses where both parents were A*. There was
no influence of gender on SM affectedness. All offspring were SM affected if
both parents were SM affected. SM affected offspring may also occur when SM
unaffected dogs are used (15.4% from A x A parent crosses and 7.7% from A* x
A* parental crosses). Using dogs of unknown status was risky for SM
affectedness. Fifty percent of older offspring were SM affected in A x U
parental crosses and there were higher numbers of SM affected dogs with
other parental combinations that included one Grade U dog. In conclusion, to
increase the number of SM unaffected offspring, at least one parent should
be ascertained to be free of SM by MRI at 2.5 years of age. Ideally both
parents would be free of SM at 2.5 years of age and the true SM status of
the grandparents at least 5 years old should be established. It is
recommended that all breeding dogs from breeds susceptible to CMSM be MRI
screened and results submitted to an officially recognised central
database."
Brachycephalic Airway Obstructing Syndrome: Some Further Controversies
Robert N. White. Assn. of Veterinary Soft Tissue Surgeons. Oct. 2010. Quote:
"The
Cavalier King Charles
spaniel
also warrants further discussion. Previous reports from the
UK and Australia would suggest that this breed in commonly presented for the
investigation and management of BAOS (Lorinson and others 1997, Torrez and
Hunt 2006) in both these countries. Surprisingly, a recent retrospective
series of 62 dogs from North America (Riecks and others 2007) contained no
individuals of the breed. Like the three breeds discussed above [Yorkshire
terrier, the Norfolk terrier and the Norwich terrier], it is my experience
that the
Cavalier King Charles spaniel
presented for the
further investigation of ʻBAOSʼ commonly does not have the classic findings
seen in the bulldog, French bulldog, Pekinese, Pug, etc. Their
nasopharyngeal obstruction is often characterised by a subjectively narrow
(smaller than expected for a breed of their size) nasopharyngeal space and
it is quite common that they do not show evidence of overlength of the soft
palate. Interestingly, a recent report (Hayes and others 2010) confirmed a
significant association between the presence of otitis media with effusion
(on MRI) and an increase thickness of the soft palate and reduced
nasopharyngeal aperture. Many of the cases show evidence of otitis media
with effusion (OME) on either otoscopic examination or other imaging studies
of the tympanic bullae. Malformation of the nasopharynx and soft palate is
recognised to be associated with the formation of otitis media with effusion
in the dog (White and others 2009). The prevalence of caudal fossa
(craniocervical junction abnormalities including occipital hypoplasia)
malformations is high in the
Cavalier King Charles spaniel
and is considered to be associated with the presence of neurological signs
observed in individuals suffering from cerebellar herniation and
syringohydromyelia (Cerda-Gonzalez and others 2009). It would seem
reasonable to hypothesise that the
Cavalier King Charles spaniel
might suffer from a syndrome of conditions (syringomyelia, OME,
nasopharyngeal airway obstruction, etc.) that are all associated with the
malformation of the caudal aspect of the skull."
Morphometric Assessment
Of Cranial Volumes In
Age-Controlled
Cavalier King Charles Spaniels
With And
Without Syringomyelia
. C. J. Driver, C. Rusbridge, I. M. McGonnell, H.
A. Volk. Vet.Rec.; Dec 2010; 167:978-979. Quote: "
Cavalier King
Charles spaniels (CKCS
) with Chiari-like malformation (CM) and
syringomyelia have more brain parenchyma within the caudal cranial fossa
(CCF) (CCFP), and also display ventriculomegaly, compared with
CKCS
with CM alone (Driver and others 2010). ... This short communication
describes a retrospective, volumetric comparison of three variables (CCF,
CCFP and ventricular dimensions) between
CKCS
with syringomyelia when less
than two years of age and
CKCS
older than five years without syringomyelia.
... Dogs were grouped into those diagnosed with CM and syringomyelia when
less than two years of age, and those with only CM aged five years or older
when scanned. ... There was a significant difference in ventricular
dimensions between the young dogs with syringomyelia ... and the unaffected
older dogs ... Similarly, mean (sd) CCFP was significantly different between
the groups.... Furthermore, the young
CKCS
with syringomyelia had a smaller
mean ... than the unaffected older dogs  ... These results are
consistent with previous findings that ventriculomegaly and a small but
significant increase in caudal fossa parenchyma are associated with
syringomyelia (Driver and others 2010). The present results suggest that the
CCF volume is also significantly smaller in dogs with syringomyelia. ... The
development of syringomyelia may be related to a cumulative effect of a
small CCF and enlarged CCFP; however, as there is little difference between
the measurements numerically, it is unknown how this would affect
CKCS
clinically and biologically. Further cohort and longitudinal studies are
required to assess whether measuring the ventricular dimensions would be
useful in differentiating
CKCS
that will develop syringomyelia from those
that will not."
RETURN TO TOP
2011
Distribution
of syringomyelia
along the entire spinal cord in clinically affected
Cavalier King Charles Spaniels
. Shenja Loderstedt,
Livia Benigni, Kate Chandler, Jacqueline M. Cardwell, Clare Rusbridge,
Christopher R. Lamb, and Holger A. Volk. Vet.J. 2011 187:---. Quote:
"Chiari-like malformation (CM) and syringomyelia (SM) is an important
disease complex in the
Cavalier King Charles Spaniel (CKCS)
but data about the anatomical distribution of SM along the spinal cord are
lacking in veterinary medicine. The objective of this study was to define
the anatomic distribution of SM in
CKCS
clinically affected
by CM/SM. Magnetic resonance imaging (MRI) of the brain and the entire
spinal cord of 49 dogs was performed and different morphological parameters
compared. ... CM was present in all patients. ... All dogs in the present
study were clinically affected. ... SM was absent in 25% of dogs with
clinical signs. ... {I}maging only the cervical spine in clinically affected
CKCSs
is likely to underestimate the total syrinx size and
the anatomical distribution of SM. The presence of cervical SM in all dogs
with MRI evidence of SM could however justify the restricted imaging under
screening purposes. ... In the majority of cases in our study, the syrinx
borders were not well demarcated on T2-weighted MR images. Syrinx outlines
were however distinctly visible in T1-weighted images. ... The results of
our study showed syrinx formation in all regions of the spinal cord with no
significant differences of [syrinx size] between the cervical,
cervicothoracic and thoracolumbar regions, but significantly smaller syrinx
in the caudolumbar spinal region. ... In our study Smax was most often seen
within the C1-C4 region and, interestingly, also over T2-L2 vertebral
bodies. ... Our data offer a description of the distribution and size of SM
in clinically affected CKCS and challenge the current pathophysiological
theories. ... We found that the severity of SM was positively correlated
with patient age. This is consistent with previous studies indicating that
CKCS
with SM were significantly older than dogs without SM
(Couturier et al., 2008). It seems likely therefore, that SM is a
progressive disease in dogs. ... There is a very high potential for
CKCS
with clinical signs of CM/SM to develop SM in more than one
spinal cord region. Diagnostic imaging limited to the cervical spine in
clinically affected
CKCS
is likely to underestimate the
degree and severity of SM. It can be hypothesised that SM has a progressive
nature in
CKCS
, which requires further characterisation."
Corticosteroid & Nonsteroidal Antiinflammatory Drug Interactions
Patricia Dowling. Clinician's Brief. March 2011;89-92.
Growth of Clinical Veterinary Magnetic Resonance
Imaging.
Patrick R. Gavin. Vet.Rad. & Ultra.; Mar/Apr 2011;
52(s1):52-54. "In the spine, MR imaging reveals conditions which were
previously difficult to diagnose ante-mortem, and may facilitate study of
their pathophysiology. Examples include syringohydromyelia associated with
Chiari-like malformation in the
Cavalier King Charles spaniel.
..
."
Correlating Magnetic Resonance Findings with
Neuropathology and Clinical Signs in Dogs and Cats
. Charles H. Vite,
Johnny R. Cross. Vet.Rad. & Ultra. Mar/Apr 2011; 52(1),Supp. 1:S23-S31.
Evaluation of cerebrospinal fluid
in
Cavalier King Charles
Spaniel
dogs diagnosed with Chiari-like malformation with or
without concurrent syringomyelia
. Whittaker DE, English K, McGonnell
IM, Volk HA. J Vet Diagn Invest. 2011 Mar;23(2):302-7. "Syringomyelia is a
common clinical problem in the
Cavalier King Charles Spaniel
dog population. The underlying pathophysiology of the development and
progression of syringes is currently unknown. The primary aim of the current
study was to determine whether development of syringomyelia is accompanied
by alterations in cerebrospinal fluid composition. Patient records of
Cavalier King Charles Spaniels
with Chiari-like
malformations, with or without concurrent syringomyelia, that had magnetic
resonance imaging and cerebrospinal fluid analysis between December 2004 and
December 2009, were retrospectively reviewed. Total nucleated cell count per
microliter, with differential count, red blood cell count per microliter,
and protein concentration (g/l), were reviewed. Data were analyzed with the
Mann-Whitney U-test. Spearman rank test was used to test association between
cerebrospinal fluid composition and syrinx size, and the Fisher exact test
was used to compare the presence of macrophages, reactive lymphocytes, and
myelin. A P value of ≤0.05 was considered significant for statistical tests.
Dogs with syringomyelia had a higher total nucleated cell count
(syringomyelia: 4/μl [range, 0-15/μl] vs. without syringomyelia: 2/μl
[0-8/μl]; P  =  0.0047), higher protein concentration (syringomyelia: 0.26
g/l [0.07-0.42 g/l] vs. without syringomyelia: 0.2 g/l [0.12-0.39 g/l]; P
=  0.039), and an increased neutrophil percentage (syringomyelia: 0%
[0-37%] vs. without syringomyelia: 0% [0-21%]; P  =  0.0203) than those with
the Chiari-like malformation alone. There was a positive correlation between
total nucleated cell count and syrinx size (r  =  0.51; P  =  0.0068).
Development of syringomyelia is accompanied by alterations in cerebrospinal
fluid composition. The pathogenesis of syringomyelia has not been fully
elucidated; therefore, the exact origin of cerebrospinal fluid changes
remains unclear."
Syringomyelia in
Cavalier spaniels
treated successfully with palmitoylethanolamide (PEA)
. Jan M. Keppel
Hesselink. Instituut voor Neuropathische Pijn. April 2011.  Quote: "In
central neuropathic pain inflammatory and gial pathology might play a more
important role than we previously thought. Recently in this field new
drugtargets emerged and research into the treatment of central neuropathic
pain is now slowly unfolding. One of those targets is the glia, and the
phrase gliopathic pain has been used to point out the importance of the glia
in neuropathic pain. The enodcannabinoid palmitoylethanolamide is a new
analgesic compound within this new field. We conducted a pilot trial using
palmitoylethanolamide in a animal model for central neuropathic pain, the
cavalier KIng Charles spanie
l, suffering from Arnold Chiari
malformations and syringomyelia, and exposing classical pain behaviour. ...
Central neuropathic pain is a prominent feature in 50 to 90% of adult human
patients with syringomyelia. Recently, a direct relationship has been
described between central neuropathic pain and objective markers of spinal
cord damage. Large syrinxes leading to damage to the dorsal part of the
spinal cord are leading to abnormal behaviour seen by cavalier King Charles
spaniels. This behaviour is likely to be "neuropathic pain," and therefore
it is suggested that conventional analgesic medication may be ineffective.
... In the Netherlands we conducted an open pilot trial and included
12 Cavalier king Charles spaniels
, alle with MRI-scan positive
syringomyelia and all suffering from behavioural abnormalities and objective
signs related to syringomyelia and neuropathic pain. ... All dogs were
weaned off their analgesic medication before entering the trial. During 2
months PEA was given in a dose of around 30 mg/kg BW. So most dogs received
150 mg twice daily. If dogs are very light (less then 6 kg) we start with
PEA 200 mg. Dogs between 6-12 kg mostly get twice daily 150 mg and heavy
dogs, and non responders twice daily 200 mg. As the substance isn tolerated
very well, a bit more is no problem, up to 40 mg/kg dog. If dogs get too a
higher dose, they start painting and they become restless. A composite scale
scored by the dog owners was used, based on whether symptoms were the same,
improved a bit or improved a lot. The first item was the overall general
impression, the other items were linked to behavioural abnormalities, such
as: cheery, lively (same, better, much better); headache (eyes closed)
(same, better, much better); lacrimation (same, less, much less); chewing
and swallowing, (same, less, much less); scratching, licking, rubbing (same,
less, much less) ; moving around (same, better, much better). Results: After
2 months of PEA use in
12 Cavalier spaniels
, the results
were the following. Of all the 12 dogs, based on the overal general
impression the owners could clearly detect improvement within 8 days, and in
5 dogs the improvement was seen already after 3-4 days. Within 4 weeks all
dogs showed improvements. More specifically: General impresison: in 4 dogs
better and in 8 dogs much better. ; cheery/ lively: same 0, better: 5 much
better: 7; headache (eyes closed): same 0, better: 5, much better: 7;
lacrimation: same: 3, less: 3 much less: 6; chewing and swallowing, same: 3,
less: 3 much less: 5 (1 not scored); scratching, licking, rubbing: same: 2,
less: 5 much less: 5; moving around: same: 2, better: 2 much better: 7 (1
not scored) Qualitative statements of owners One owner states she can pat
the dog again, and the dog played again with younger dogs. Some owner stated
that the dog's skull was less hot. One owner of a dog suffering from chronic
ear inflammation (PSOM) could tough the dogs head and ears again. In one dog
the owner stated that the lordosis vanished, one other dog showed affective
behaviour and touching was again possible, etc, etc. All dog owners noticed
impressive positive changes in behaviour after treatment with PEA.
Follow-up: meanwhile many dogs are treated for many months, and most dogs
are still very much stable. The first signs of efficacy is less inflammation
of the eyes, and less lacrimation, already sometimes after some days. As
syringomyelia is a spinal cord condition, is it important to point out that
palmitoylethanolamide has been evaluated in other models of spinal cord
injury too. And these models supported its therapeutic role.
Palmitoylethanolamide is the naturally occurring amide of palmitic acid and
ethanolamine. In a great number of pharmacological trials this molecule has
been shown to reduces pain and inflammation through the nuclear receptor
PPAR-alpha. This receptor is activated by PEA. PEA can reduce secondary
damage induced by experimental spinal cord injury (SCI) in a mice model. SCI
leads to edema, neutrophil infiltration, and production of inflammatory
mediators, tissue damage, and apoptosis. Repeated PEA administration
significantly reduced: •1) the degree of spinal cord inflammation and tissue
injury; •2) neutrophil infiltration; •3) nitrotyrosine formation; •4)
proinflammatory cytokine expression; •5) nuclear transcription factor
activation-kappaB activation; •6) inducible nitric-oxide synthase
expression; and •6) apoptosis. Hand in hand with these biochemical
improvements, PEA ameliorated the recovery of motor limb function. In a
compression model induced by applying an aneurysm clip to the spinal cord in
mice repeated PEA administration (10mg/kg i.p., 6 and 12h after SCI)
significantly reduced the degree of the severity of spinal cord trauma
through the reduction of mast cell infiltration and activation. PEA also
significantly reduced the activation of microglia and astrocytes expressing
cannabinoid CB(2) receptor after SCI. PEA also acted as a neuroprotectant
via induction of neurotrophic factors. The results of this pilot trial are
in line with experimental findings supporting the neuroprotective role of
PEA, as well as its role as a anti-inflammatory and analgesic compound. The
avaiibility of Normast [Peapure] for human and dog sufferers of central neuropathic
pain is a leap forward in the treatment of this difficult to treat pain
state."
Effects of
syringomyelia
on electrodiagnostic test results in
Cavalier King
Charles Spaniels
. Thomas R. Harcourt-Brown, Zoe Belshaw, John
E. Parker, Nick D. Jeffery,  Nicolas Granger. Am J Vet Res, May
2011;72(5):595-600. Quote: "Objective -- To determine the effects of
syringomyelia on electromyography (EMG) findings, somatosensory-evoked
potentials (SEPs), and transcranial magnetic motor-evoked potentials
(TMMEPs) in
Cavalier King Charles Spaniels (CKCSs).
Animals
--
27 client-owned CKCSs
that underwent prebreeding magnetic
resonance imaging screening or investigation of clinical signs consistent
with syringomyelia. Procedures -- In dogs with (n = 11) and without (16)
magnetic resonance imaging-confirmed syringomyelia, the median nerve in each
thoracic limb was stimulated and SEPs were recorded over the C1 vertebra;
onset latency and latency and amplitude of the largest negative (N1) and
positive (P1) peaks were measured. The TMMEPs were recorded bilaterally from
the extensor carpi radialis and tibialis cranialis muscles; onset latencies
in all 4 limbs were measured. Bilateral systematic needle EMG examination
was performed on the cervical epaxial musculature, and the number of sites
with spontaneous activity was recorded. Results -- In dogs with
syringomyelia, amplitudes of N1 and P1 and the amplitude difference between
P1 and N1 were significantly smaller than those recorded for dogs without
syringomyelia (approx 2-fold difference). No difference in SEP latencies,
TMMEP latencies, or the proportion of dogs with > 2 sites of spontaneous
activity detected during EMG examination was detected between groups.
Conclusions and Clinical Relevance -- Results indicated that SEP amplitude at
the C1 vertebra was a more sensitive measure of spinal cord function in
CKCSs
with syringomyelia, compared with results of EMG or
TMMEP assessment. Measurement of SEP amplitude may have use as an objective
assessment of the evolution and treatment of this disease."
Whole Genome
Study Identifies
a Candidate Region for Chiari-like Malformation in
Brussels Griffon
.   LeMay P, Trinh QH, Dube MP, Rusbridge C, Rouleau
GA, and Kibar Z. Sainte-Justine University Hospital Center Research Center
18 June 2011. Quote: "Chiari malformation type 1 (MCI) ... in humans is
similar to a disease in dogs called Chiari-like malformation (CM). This
disease has a particularly high incidence in the Brussels Griffon breed
(GB). ... Results: Analysis of type case / control genotypes generated by
the study of whole-genome association identified six genomic regions with
significant scores. ...[A] genomic region on chromosome 2 was significantly
associated with MC (P = 1.9x10-5 when corrected EIGENSOFT). Haploview
identified a haplotype block extending over a region of 2.9 Mb which is
significantly associated with CM with a P value of 6.87 x10-10. The fine
mapping has identified three new SNPs significantly associated with CM with
P values of 1.938x 10-6, 1.61x 10-5, 5.36x 10-6 in addition to allowing a
reduction in haplotype 1.7 Mb.  Conclusion: A region of a 1.7 Mb on
chromosome 2 is associated with CM in the GB. To reduce this region, other
breeds genetically related to GB and affected by CM will be genotyped to
identify a region shared by CM affected. In addition, a case / control over
a larger cohort will increase the resolution of this region."
Prevalence of
asymptomatic
syringomyelia in
Cavalier King Charles spaniels
J. E. Parker, S. P. Knowler, C. Rusbridge, E. Noorman, N. D. Jeffery. Vet.J.
June 2011;168(25):667. Quote: "The prevalence of syringomyelia was investigated in a
sample population of
555 Cavalier King Charles spaniels
All dogs, which were declared by their owners to be showing no clinical
signs of syringomyelia, underwent MRI to determine the presence or absence
of the condition. Data were analysed by logistic regression to determine the
effects of sex and age on the prevalence of syringomyelia. Only increased
age was found to have a significant effect. The prevalence of syringomyelia
was 25 per cent in dogs aged 12 months, increasing to a peak of 70 per cent
in dogs aged 72 months or more. ... The evidence for a lower prevalence in
younger animals is more reliable (because of the higher numbers included in
the present study and the lower likelihood of false inclusion) and this
effect lasts until dogs are at least three years of age. This finding has
important implications for the design of a screening test procedure and may
conflict with the current recommendations that the optimum age for screening
should be 30 months. These data would imply that it is probable that dogs
aged up to three years may yet have reduced odds for the diagnosis of
syringomyelia. However, there is a need for the dogs to be screened when
they are reasonably young so that breeders can decide at an early stage
whether their animals are suitable for breeding; many breeders would
consider 36 months unduly old.... The high lifetime prevalence of
syringomyelia raises concerns for the welfare of the
CKCS
breed and also suggests that eliminating the genetic risk factors for the
disease by selective breeding may be difficult, because the heritability has
previously been shown to be complex, and the prevalence of the determinant
genes within the population is therefore likely to be high. The true
prevalence of syringomyelia in the general
CKCS
population
is expected to be higher than that found in this sample population because
symptomatic dogs were specifically excluded."
reliminary Morphometric Evaluation of Syringomyelia
in American Brussels Griffon Dogs
. A.C. Freeman, S.R. Platt, M. Kent,
E. Huguet. J Vet Intern Med 2011;--- (ACVIM 29th Ann. Vet. Med. Forum
Abstract Program: Abstract N-3). Quote: "The aims of this study were to
investigate the ABG for (i) the prevalence of skull abnormalities; (ii) the
prevalence of SM; (iii) an association between lateral ventricular size,
cerebellar size and SM; and (iv) associations between SM, skull
abnormalities, CSF pleocytosis and clinical signs. Seventy-six ABGs,
recruited as part of a larger epidemiological and genetic study, underwent
brain and spinal MRI evaluation ... . All dogs were evaluated
neurologically, recording deficits and the presence of spinal pain. ... . Forty-five dogs underwent atlanto-occipital cerebrospinal
fluid tap at the time of MRI and the white blood cell (WBC) count was
recorded. ... The mean age of the 30 males (24 intact) and the 46
females (34 intact) was 50.4 months (range 8-135; median 44 months).
Neurological deficits and neck pain were noted in 21 (27%) and 15 (19.7%) of
dogs respectively; 5 dogs (6.57%) exhibited both. Cerebellar deviation and vermal herniation were present in 37 (48.68%) and 46 (60.52%) dogs
respectively; twenty-three dogs (30.26%) had both. Mean height of the CC was
2.3mm (0-7.2 mm). Forty (52.63%) Ccs were greater than 2mm in height; the
mean length of these lesions was 2.03 vertebrae (0.5-7). Mean CSF WBC count
was 4.97/μl (0- 39). Syrinx height and extent were significantly higher in
dogs with neurological signs (size p = 0.01; extent p 5= 0.0004). There were
no significant differences in syrinx sizes and extent in dogs with or
without skull abnormalities or spinal pain. There were no associations of
syrinx height or extent with CSF WBC count or age of dog. Intact females had
a significantly lower syrinx extent than intact males (p = 0.009). There
were no significant differences in presence of spinal pain or neurological
signs between dogs with or without skull abnormalities. There was a
significant negative association of ventricular percentage and cerebellar
percentage (p < 0.0001). There was a significant association of ventricular
percentage with syrinx percentage (p = 0.0015) and height (p = 0.0007). This
study suggests that SM and CM are prevalent in ABGs. Syrinx size and extent
are associated with neurological signs and ventriculomegaly is associated
with both small cerebellar size and large syrinx size. However, SM may not
be associated with CM as defined by cerebellar herniation and deviation and
is not associated with CSF inflammation."
Chiari-like Malformation, Syringomyelia and
Neuropathic Pain: Cerebrospinal Fluid Neurotransmitter and Cytokine Levels
S.R. Platt, A.C. Freeman, M. Kent, E. Huguet, G. Edwards, R. Barber. J Vet
Intern Med 2011;--- (ACVIM 29th Ann. Vet. Med. Forum Abstract Program:
Abstract 93B). Quote: "The pathogenesis of neuropathic pain (NP) and
syringomyelia (SM) in association with Chiari-like malformation (CLM) in
dogs has focused on the anatomical anomalies and secondary cerebrospinal
fluid (CSF) flow abnormalities. Neuropathic pain in humans has been
associated with abnormalities of neurotransmitters such as glutamate and
serotonin as well as immunologic mechanisms. The aim of this study was to
investigate the CSF neurotransmitter and cytokine levels in Brussels Griffon
dogs (BGs) with CLM, SM and NP.
Relationship
of Cerebellar Volume
to Syringomyelia in the
Cavalier King Charles Spaniel
. TA Shaw, I McGonnell, CJ
Driver, C Rusbridge, HA Volk. J Vet Intern Med 2011;--- (ACVIM 29th Ann.
Vet. Med. Forum Abstract Program: Abstract N-12). Quote: "The objective of
this study was to assess the role of cerebellar volume in caudal cranial
fossa overcrowding and syringomyelia. ... Forty-five small breed dogs (SB),
58 CKCS
and 31 Labradors (LD) were compared. As SM is
thought to be a late onset disease process, two subgroups were formed for
comparison: 21 CKCS younger than 2 years with SM (group 1) and 13
CKCS
older than 5 years without SM (group 2).
CKCS
had a larger cerebellar caudal cranial fossa percentage than the other
groups (CKCS 52.19% [40.07-58.76%] vs. SB 47.81% [40.36-62.91%] and LD
41.32% [32.59-52.95%]; p o 0.001). The cerebellar brain percentage was also
larger in CKCS compared to the other groups (
CKCS
8.90%
[6.62-11.46%] vs. SB 7.37% [5.25- 11.34%] and LD 7.23% [6.36-9.54%]; p o
0.001). Group 1 had a significantly larger cerebellar caudal cranial fossa
percentage than group 2 (53.71% 1.27 vs. 49.31% 2.35, p 5 0.001) and a
significantly larger cerebellar brain percentage (9.45% 0.43 vs. 8.58% 0.55,
p 5 0.021). Our findings show that the
CKCS
has a
relatively larger cerebellum than small breed dogs and Labradors and there
is an association between increased cerebellar volume and SM in
CKCS
." es were analysed
for presence of serotonin (ng/ml), glutamate, glycine and GABA (mg/ml) by
high performance liquid chromatography. ... All hypothesis tests were
2-sided and the significance level was á = 0.05. NP was detected in 8 dogs
(17%); SM was present 24 dogs (52%); and CM was detected in 24 dogs (52%).
IFN-g levels were significantly lower in dogs with NP than without (p =
0.036). There were significant positive correlations between syrinx size and
IL-8 (p = 0.017),KC(p = 0.025) and MCP-1 (p = 0.003). There were significant
negative correlations between IFN-g and syrinx height (p = 0.025) and extent
(p = 0.042). There was a significant negative correlation between IL-2 and
syrinx height (p = 0.042). Neurotransmitter levels were not associated with
skull abnormalities or spinal pain, but there was a positive correlation of
glycine with IL-2 (p = 0.004) and MCP-1 with glutamate (p = 0.0147) and
serotonin (p = 0.0059). The size of the syrinx in BGs with SM is associated
with several cytokine elevations but only a decrease of IFN-g was associated
with NP. Based on this study it does not appear that excitotoxicity plays a
role in either SM development or NP. Further work is justified on the role
of the immune system in CM, SM and NP."
Effect of Omeprazole
on Serum Gastrin Concentrations and Calcium Metabolism in Healthy Dogs
O. Dossin, K. Jones, M. Ridgway, S. Clark-Price, JM. Steiner, JS.
Suchodolski. J Vet Intern Med 2011;--- (ACVIM 29th Ann. Vet. Med. Forum
Abstract Program: Abstract GI-5). Quote: "Proton pump inhibitors (PPI) are
widely used in human and also veterinary medicine. Side-effects of PPI
treatment reported in people are atrophic gastritis, gastric and esophageal
cancer, and rebound hyperacidity following cessation of treatment, which has
been speculated to be due to a sustained increased in circulating gastrin
concentration. Moreover, long-term PPI treatment has been associated with an
increased risk for osteoporosis in people. Little is known about the effect
of PPI treatment on serum gastrin concentration or calcium metabolism in
dogs. Eight healthy adult research dogs (4 males and 4 females) were
enrolled into the study. The dogs received an average dose of 1.1 mg/kg of
omeprazole orally twice daily for 15 days. ... This study shows that
treatment with omeprazole for 2 weeks results in a profound and sustained
increase in serum gastrin concentration in dogs. This effect is rapidly
reversible after cessation of the treatment. No effect on calcium metabolism
was observed. However, this study documents only the effect of short-term
treatment and it is possible that the effects of long-term administration
are different."
Changes over Time
in
Caudal Cranial Fossa Volumes and of Cerebellar Herniation in
Cavalier King Charles Spaniels
with Chiari-like Malformation
S. Hamilton, L. De Risio, C. Rusbridge, CJ Driver, R. Dennis, I McGonnell,
HA Volk. J Vet Intern Med 2011;--- (ACVIM 29th Ann. Vet. Med. Forum Abstract
Program: Abstract N-13). Quote: "There is currently a lack of information if
the morphological changes seen in
CKCS
with CM are
progressive or non-progressive. In this retrospective study we used
established measurements of cerebral volumes, foramen magnum height and
cerebellar herniation length to assess if there is a significant difference
between subsequent magnetic resonance (MR) imaging of the brain of the same
dog. Electronic patient records were reviewed for
CKCS
with
CM which had two separate MRI scans, which were a minimum of 3 months apart.
CKCS
with diseases affecting measurements were excluded.
... Volumes of the caudal cranial fossa parenchyma were analyzed as
percentages of caudal cranial fossa volume and caudal cranial fossa volume
was analyzed as a percentage of total cranial cavity volume. The volume of
the ventricular system was recorded as a percentage of total parenchymal
volume. Data was assessed for normality and the appropriate statistical test
was used to compare means/medians. Twelve
CKCS
were
included with a median scan interval of 9.5 months (3-83 months). The size
of the foramen magnum increased significantly between the first and second
scan ..., as did the length of
cerebellar herniation ... There was no significant difference noted between
the two time points in any of the other volumetric measurements ... This work
could suggest that overcrowding of the caudal cranial fossa in conjunction
with the movements of cerebrospinal fluid and cerebellar tissue secondary to
pulse pressures created during the cardiac cycle causes pressures on the
occipital bone. This leads to a resorption of the bone and therefore an
increase in caudal cranial fossa and foramen magnum size allowing cerebellar
herniation length to increase."
Morphometric Features of the Craniocervical Junction
Region in Dogs with Suspected Chiari-like Malformation: 274 Cases
(2007-2010)
. Dominic J. Marino. J Vet Intern Med 2011;--- (ACVIM 29th
Ann. Vet. Med. Forum Abstract Program: Abstract 95A). Quote: "Concurrent
malformations of the cranio-cervical junction are commonly identified in
humans with Chiari type I malformation. Recent evidence suggests such
craniocervical junction abnormalities (CJAs) also occur in dogs suspected of
having Chiari-like malformation (CLM). The purpose of this study was to
objectively describe morphometric features of the craniocervical junction
region of dogs with suspected CLM and to investigate for associations
between these features and the occurrence of other malformations in this
region. Magnetic resonance (MR) and computed tomographic (CT) images from
274 dogs with CLM were evaluated. Three regions of neural tissue compression
were assessed: cerebellar compression (CC); ventral compression at the C1/C2
articulation, termed ''medullary kinking'' (MK); and dorsal compression (DC)
at the C1/C2 articulation. A compression index (CI) was calculated for all
abnormal regions for each dog. Multiple logistic regression analysis was
performed (p o 0.05) to ascertain whether CI values for the different
regions of compression were associated with the incidence of other cranio-cervical
junction abnormalities. 68% of dogs had MK and 38% of dogs had DC. 28% of
dogs also had evidence of atlanto-occipital overlapping (AOO). Breed and
severity of CC were the only significant predictors of AOO (p o 0.0001 and
po0.0092). 28% of suspected CLM cases have AOO as the anatomic abnormality
responsible for CC. Compression index values may help differentiated
subtypes of CJAs in dogs."
Medical Infrared
Imaging
(Thermography) of Type I Thoracolumbar Disk Disease in
Chondrodystrophic Dogs
. CA Loughin, DJ Marino. J Vet Intern Med
2011;--- (ACVIM 29th Ann. Vet. Med. Forum Abstract Program: Abstract 95B).
Quote: "Medical infrared imaging (MII) is a non-invasive diagnostic imaging
technique that measures skin surface temperature and generates thermal
pattern maps based on predetermined color scales. Because skin temperature,
dependent on regional perfusion, is under direct control of the sympathetic
nervous system, MII provides information about the function of the autonomic
nervous system. Because of recent advances in technology and lack of
sedation needed to image patients, MII has potential use as a screening test
for a variety of conditions that may result in autonomic dysregulation like
Chiari-like malformation in dogs (CLM). The purposes of this study were to
establish a MII protocol for dogs suspected of having CLM, to identify
thermal imaging patterns for various regions of interest (ROI), to evaluate
changes in thermal patterns and compare the results to those of MRI
findings, considered the standard for diagnosing CLM in dogs.
One
hundred and five Cavalier King Charles Spaniel dogs
with clinical
signs attributable to CLM and confirmed CLM with MRI were evaluated with a
complete blood count and chemistry profile, examination by a board certified
surgeon/neurologist, mult-idetector CT scan of the cranio-cervical junction,
whole body MRI and MII. The protocol for thermal imaging included cranial
and caudal views of the body, full lateral right and left body views, dorsal
views of the head and body, and right and left lateral views of the head.
Thermal patterns were assessed with custom image recognition software. After
each dog was imaged awake, general anesthesia was administered and the dogs
re-imaged using the same protocol. MRI findings in dogs with severe or
moderate cerebellar compression and cerebellar herniation were compared with
MII results. The top of head and front of head ROI were 89.2% and 97.3%
successful in identifying dogs with CLM. Based on these preliminary
findings, MII may be a viable screening tool to detect CLM in dogs."
Cephalometric
Measurements
and Determination of General Skull Type of
Cavalier
King Charles Spaniels
M. J. Schmidt, A. C. Neumann, K. H.
Amort, K. Failing, M. Kramer. Vet. Rad. & Ultra, 26; Jul/Aug 2011;52(4):436-440. Quote: "The
general skull morphology of the head of the
Cavalier King Charles
Spaniel (CKCS)
was examined and compared with cephalometric indices
of brachycephalic, mesaticephalic, and dolichocephalic heads. Measurements
were taken from computed tomography images. Defined landmarks for linear
measurements of were identified using three-dimensional (3D) models. The
calculated parameters of the
CKCS
were different from all
parameters of mesaticephalic dogs but were the same as parameters from
brachycephalic dogs. However, the
CKCS
had a wider
braincase in relation to length than in other brachycephalic breeds. Studies
of the etiology of the chiari-like malformation in the
CKCS
should therefore focus on brachycephalic control groups. As Chari-like
malformation has only been reported in brachycephalic breeds, its etiology
could be associated with a higher grade of brachycephaly, meaning a shorter
longitudinal extension of the skull. This has been suggested for other
breeds."
Understanding Chiari-like
malformation: where are we now?
Rita Gonçalves. Vet Rec Sept
2011;169:275-276. Quote: "Over recent years, numerous studies have been done
to try to enhance our understanding of CM in the
CKCS
Several studies used morphometric measurement methods to quantify the size
of the different components of the caudal cranial fossa (CCF) and quantify
the degree of mismatch between them and the CCF. Initial studies suggested
that
CKCS
with CM/ syringo-myelia have a smaller relative
caudal fossa area, compared with control dogs such as labradors (Carrera and
others 2009). However, subsequent studies failed to find the same
association when comparing the caudal fossa of CKCS with and without
syringomyelia using three-dimensional measurement methods (Cerda-Gonzalez
and others 2009, Schmidt and others 2009, Driver and others 2010a).
CKCS
have also been shown to have proportionally the same volume of
parenchyma within the CCF as labradors (Cross and others 2009). A more
recent study considered the fact that signs of syringomyelia often only
shows at an older age. In this study,
CKCS
with CM older
than five years of age (controls) were compared with
CKCS
with CM/syringomyelia aged two years or less. This revealed a significantly
smaller CCF in
CKCS
with CM/syringomyelia (Driver and
others 2010b). Recently it was also shown that a more marked overcrowding of
the CCF due to an increased brain parenchyma volume is associated with
syringomyelia (Driver and others 2010a, 2010b). A combined evaluation of
these findings suggests that a combination of a reduced CCF and an increase
in the parenchyma contained within the CCF most likely contribute to the
pathogenesis of this complex condition. ... It is common to detect CM in
dogs presenting for other problems, and a study recently published in
Veterinary Record showed that the prevalence of syringomyelia in dogs
considered asymptomatic by their owners was 25 per cent in dogs aged one
year and 70 per cent in those aged six years or more (Parker and others
2011). This discrepancy between the imaging findings and the clinical signs
poses a major difficulty when designing studies aimed at improving our
knowledge about this condition. These results also have important
implications in the design of a screening test procedure, which was
previously recommended for dogs aged two to three years, and suggests that
eliminating the disease by selective breeding may be virtually impossible.
... In a paper summarised in this issue of Veterinary Record, Upchurch and
others (2011) aimed to investigate the effect of positioning of the dog's
head during MRI on the severity of CM, ... Chiari-like malformation has for
a decade now been widely identified in the
CKCS
population
but despite its high prevalence, little is still known about its
pathogenesis. Further studies are necessary to increase our understanding of
this condition in order to allow the development of new treatment options
and improve the welfare of the
CKCS
affected."
Influence of head positioning
on
the assessment of Chiari-like malformation in
Cavalier King Charles
spaniels
J. J. Upchurch, I. M. McGonnell, C. J. Driver, L.
Butler, H. A. Volk. Vet Rec Aug 2011; 169(11):277.
Quote: "Chiari-like malformation (CM) is almost
omnipresent in the
Cavalier King Charles
spaniels (CKCS)
, often leading to syringomyelia (SM). Morphometric
studies have produced variable results concerning relationship between the brain
parenchyma within the caudal cranial fossa (CCF) and SM. The present study
assesses the effect of head position, one potential confounder. Magnetic
resonance images of
CKCS
with CM were reviewed in extended and
flexed head positions. ...
Fourteen CKCS
were included into the study, seven dogs with CM and seven with CM/SM. ...
The degree of cerebellar herniation was significantly worse in dogs with a
flexed compared to an extended head position. ... Cerebellar herniation did
not differ significantly between
CKCS
with and without SM
in the extended head position. However, in the flexed head position the
cerebellum herniated more caudally in CKCS with CM/SM compared to
CKCS
with CM alone. This highlights that the non-flexed head
position may underestimate the true extent of cerebellar herniation and
could explain why previous studies have missed an association with SM. ...
It is well documented that flexing the head opens the CSF space of the
cisterna magna and this could explain the morphometric measurements. The
brainstem reduces in size to accommodate this increase in CSF space. ...
When CSF space between the cerebellum and brainstem was compared in
CKCS
with and without SM, there was a significant increase in CSF
space in
CKCS
with CM alone compared to those with CM/SM
when head position was flexed. ... The reduced CSF space in CM/SM dogs
reported in this study could explain this jet like CSF flow in dogs with
CM/SM compared to those with CM alone. ... Furthermore, there is an
association between head position and level of foramen magnum overcrowding.
Based on these findings it may be appropriate to position patients in a more
flexed head position for optimal imaging in order to identify morphologic
changes more accurately. This is important to consider for imaging
CKCS
with CM especially when studying the pathogenesis of CM/SM. It
should also be considered when taking a cisternal CSF sample as the spinal
needle might be traumatic to the herniated cerebellum."
Histopathological Investigation
of Syringomyelia in the
Cavalier King Charles Spaniel
H.Z. Hu, C. Rusbridge, F. Constantino-Casas, N. Jeffery. J Comp Path. Sept.
2011. Quote: "Syringomyelia (SM) in
Cavalier King Charles spaniels
(CKCSs)
is identified commonly on magnetic resonance images and is
sometimes associated with clinical signs of pain and cervical hyperaesthesia.
However, the mechanism by which SM develops in this breed has not been fully
elucidated and the associated effects on spinal cord structure have not been
reported previously. The aims of this study were to describe changes found
in the spinal cord of
CKCSs
, to compare findings between
symptomatic and asymptomatic dogs and to determine whether syrinx formation
was associated with tissue destruction. Anomalies of the central canal were
found in all specimens and many dogs had grossly visible fluid-filled
cavities within the spinal cord. Prominent microscopical findings were
spongy degenerative changes associated with neuronal necrosis and Wallerian
degeneration. The ependyma was discontinuous in many specimens, notably in
symptomatic individuals, and there was evidence of angiogenesis and fibrous
tissue proliferation around blood vessels adjacent to syrinx cavities.
Compared with two different samples of the normal dog population, dogs with
syrinxes had significantly less grey matter, although this decrease was
associated with generalized loss of spinal cord area. Therefore, SM is
associated with degenerative changes in the spinal cord and may develop
through primary disruption of ependymal integrity followed by vascular
hypertrophy and proliferation. Glial and fibrous proliferation appears to be
associated with expression of clinical signs. ... The pathology suggested
that the primary development of syringomyelia is associated with central
canal dilatation and damage which is accompanied by blood vessel changes.
This is an important finding because there is so much debate on how
syringomyelia develops in all species."
Distribution of substance P
and
calcitonin gene-related peptide in the spinal cord of
Cavalier King
Charles Spaniels
affected by symptomatic syringomyelia
. Hilary
Zhaoxu Hu, Clare Rusbridge, Fernando Constantino-Casas, Nick Jeffery.
Research in Vet Sci;
Aug 2012; 93(1):318-320. Quote: "The
causes of clinical signs associated with syringomyelia in the
Cavalier King Charles Spaniel (CKCS)
are incompletely understood.
In this study we compared expression of two pain-related neuropeptides:
substance P (SP) and calcitonin gene related peptide (CGRP), in the spinal
cord dorsal horn of normal dogs with that in
CKCS
with and
without clinical signs of syringomyelia. There was a decrease in expression
of both peptides in
CKCS
with 'symptomatic' syringomyelia
that was also associated with significant asymmetry in SP-I and similar,
though non-significant, asymmetry in CGRP-I compared with other groups. ...

This current study provides evidence to suggest that
the disruption of the dorsal horn structure is a significant event in the
production of clinical signs in
CKCS
. The spinal cord
dorsal horn in symptomatic
CKCS
is significantly more
asymmetric than that of control animals, whereas the asymptomatic
CKCS
have changes that are midway between control and symptomatic
CKCS
. This suggests the possibility that progression from
mild to severe asymmetry in
CKCS
is associated with
development of clinical signs; however such a conclusion cannot be
definitively supported by this study because of the cross sectional nature
of the data collected."
Effectiveness of breeding guidelines
for reducing the prevalence of
syringomyelia
. S. P. Knowler, A. K. McFadyen, C. Rusbridge. Vet Rec Oct
2011; doi:10.1136/vr.100062; Vet Rec Dec 2011;169:679-680. Quote: "Several toy breed dogs are predisposed
to syringomyelia (SM), a spinal cord disorder, characterised by fluid-filled
cavitation. SM is a complex trait with a moderately high heritability.
Selective breeding against SM is confounded by its complex inheritance, its
late onset nature and high prevalence in some breeds. This study
investigated the early outcome of existing SM breeding guidelines. Six
hundred and forty-three dogs,
550 Cavalier King Charles spaniels
(CKCS)
and 93 Griffon Bruxellois (GB), were identified as having
either one (454 dogs) or both parents (189 dogs) with MRI-determined SM
status. Offspring without SM were more common when the parents were both
clear of SM (SM-free;
CKCS
70 per cent, GB 73 per cent).
Conversely, offspring with SM were more likely when both parents had SM
(SM-affected;
CKCS
92 per cent, GB 100 per cent). A mating
of one SM-free parent with an SM-affected parent was risky for SM
affectedness with 77 per cent of
CKCS
and 46 per cent of GB
offspring being SM-affected. ... This paper serves to report the early outcome
of using the 2006 breeding guidelines for dogs contributing to a genome project
and whose pedigrees were known. The study suggested that SM-free offspring were
more likely if both parents were SM-free and SM-affected offspring were more
likely if both parents had SM. There was a trend that older SM-free dogs (*A)
only resulted when at least one parent was *A. This finding seems logical but
since *A and A grade dogs are in a minority it is problematic for breeders to
select SM-free dogs especially when the SM status of the dog can alter with age.  Often, the true SM status may not be
known until after the dog is used for breeding. In 2010, there were 2136
CKCS
litters registered with the UK kennel club
(8095 puppies). Of these, 33 per cent had a sire aged younger than 2.5 years
on the day of mating and 36 per cent had a dam younger than 2.5 years on the
day of mating. This translates as 55 per cent of the KC registered
CKCS
puppies having one parent younger than 2.5 years and 14 per
cent having both (Grahame Ford, personal communication). Thus, a
recommendation that only A or *A grade parents be used is unlikely to be
practical for breeders. If a younger SM-free dog (C grade) is mated with an
older dog (A grade), then there is greater risk for SM than with two A grade
parents. The data in the study (Tables 3 and 4) suggested that 63 per cent
(12/19) of offspring were SM-free from A or*AxC parents. This is likely to
be an overestimation of the proportion of SM-free dogs since these figures
include C grade offspring, which may develop SM as they become older.
However, it could be argued that a recommendation to include at least one A
grade dog in any proposed mating is a reasonable, practical alternative
since it allows breeders to use their younger dogs. However, a far better
proposal for prevention of SM and maintaining genetic diversity is a
proposed mate select programme using estimated breeding values (EBV). ...
The most controversial part of the 2006 breeding recommendations was that it
permitted older clinically asymptomatic SM-affected dogs to be bred to older
SM-free dogs. This was because there were only a few A grade dogs identified
when the breeding guidelines were first proposed and overuse of these might
limit genetic diversity, reducing the effective population size. This
investigation showed that a proportion of the offspring from such a cross
can be SM-free, however, in the
CKCS
, the number of
SM-affected dogs was far greater than SM-free dogs (77 per cent
SM-affected). Moreover, where these offspring had siblings, the ratio of
SM-free to SM-affected was 1:1 compared with 3.5:1 for *A or Ax*A or A
parents or 1:1.7 for D or ExU parents (Knowler and Rusbridge, unpublished
data). It is debatable whether it is ethical to knowingly breed a dog with
an inherited disease especially when the majority of the offspring may be
destined for the pet-owning public, and this study suggested that it is not
advisable to use SM-affected dogs for breeding. However, if the prevalence
of SM is as high as 70 per cent in the
CKCS
Parker
and others 2011
), this will have dire consequences for the effective
population size of the breed. Again it is hoped that using an EBV mate
select programme may allow safer parental crosses, maintaining genetic
diversity while decreasing the number of SM-affected offspring. One problem
noted with the 2006 breeding guidelines was that if the dog was deemed
asymptomatic but SM-affected when first scanned over 2.5 years old it was
attributed a grade D status. However, in some cases it was suspected, due to
the size of the syrinx, that if the dog had been scanned when younger then
the syrinx would have been apparent, in other words, the dog was actually an
E grade. It was also possible that some dogs may have been clinically
affected (ie, an F grade) as the early behavioural signs of pain from SM
and/or CM can be subtle and/or intermittent and may not be detected in a routine
clinical examination.
In addition, some breeders fail to recognise
or acknowledge clinical signs of SM and/or CM. Since the aim of the
guidelines is to reduce the incidence of early onset and clinical SM, a
future recommendation is that a D status (or equivalent) will only be
appropriate if the dog was first proved by MRI to be SM-free before 2.5
years of age. One encouraging observation was that the proportion of grade E
(SM-affected younger than 2.5 years of age) dropped from an average of 15
dogs per year in years 2004 to 2006 to 11 dogs per year in years 2007 to
2009, that is, the breeding guidelines may be achieving the goal of reducing
the risk of early onset SM, however, this hypothesis would be needed to be
tested in a more vigorous study. ... In conclusion, the results from this
study suggest that it is appropriate to continue using the breeding
guidelines for both the
CKCS
and GB until a more robust
system based on EBV or genetic testing is available. The following
modifications are suggested but it should be realised that these are the
recommendations that are based on limited data and consequently should be
subjected to further prospective vigorous study: To increase the number of
SM-free offspring, at least one parent should be ascertained to be SM-free
by MRI as a young adult. In ideal circumstances, both parents would be
SM-free. According to the study by
Parker and others (2011)
, the optimum age for this early MRI screening
is 36 months. If an SM-affected dog is used, for example, to preserve
desirable traits or to increase genetic diversity then ideally the chosen
mate would either be selected on the basis of its EBV and/or would be an
older SM-free dog (five years or older). The offspring of the proposed
mating should also be MRI scanned and ideally bred to older SM-free dogs.
The SM status of the dog when at least five years old should be established.
SM has a complex inheritance and an EBV mate select programme should allow
breeders to select safer breeding combinations. To ensure success, the
programme requires a substantial collection of accurate populationwide data.
Consequently, all breeding dogs from breeds susceptible to CM and SM should
be MRI screened and these results should be submitted to a central source.
Pedigree and clinical history from dogs presenting with clinical signs of CM
and/or SM should also be submitted to this central system. 'D' status (or
equivalent) will only be appropriate if the dog was first proved to be
SM-free before 36 months of age. Future breeding recommendations should also
take account of dogs with CCD less than 2 mm. ..."
Dorsolateral spinal cord compression at the C2-C3
junction in
two Cavalier King Charles spaniels
. K. P.
Harris,  T. C. Saveraid, and S. Rodenas. Vet Rec Oct 2011;169(16):416.
Quote: "Due to the high incidence of Chiari-like malformation (CM) and
syringomyelia (SM) in
Cavalier King Charles spaniels (CKCS)
the presentation of this breed with a history of apparent neck pain often
prompts an early suspicion for CM-SM. Conversely, CM-SM findings upon MRI
have been reported in many asymptomatic CKCS and thus other differentials
for neck pain such as vertebral trauma, meningioencephalomyelitis or
myelocompression must be exhaustively excluded. Cervical spondylomyelopathy
(CSM), also referred to as cervical vertebral malformation-malarticulation
syndrome, cervical vertebral stenotic myelopathy and wobbler syndrome among
other terms, is a common multifactorial neurological disorder affecting
mainly large/giant breed dogs. Cases of CSM have been broadly classified by
their mechanism of spinal cord and/or nerve root compression as either
disc-associated (DA-CSM) or osseous-associated (OA-CSM). This short
communication describes dorsolateral compressive lesions of the spinal cord
at the C2-C3 junction, similar to those described in giant breed dogs with
OA-CSM, in two CKCS with concurrent CM, being evaluated with MRI for neck
pain. To the author's knowledge, this is the first report of such MRI
findings in this breed. In case 1, a 13.9 kg two-year-old male neutered CKCS
presented with a three-month history of intermittent periods of apparent
discomfort manifested as very abrupt rising from rest. Two weeks earlier,
the owner had observed an isolated episode of ataxia during which the dog
fell to the left, had a left-sided head tilt and facial twitching. The dog
remained responsive to the owner throughout and returned to normal within 30
minutes. The owner also reported that the dog frequently scratched at one
ear (the side unknown). Neurological and otoscopic examination revealed no
abnormalities. Moderate to severe hyperaesthesia was
evident upon
manipulation of the cervical spine."
Use of the loop
diuretic
torsemide in three dogs with advanced heart failure.
Mark
A. Oyama, Gordon D. Peddle , Caryn A. Reynolds, and Gretchen E. Singletary.
J Vet Cardio; Oct 2011; doi:10.1016/j.jvc.2011.10.001. Quote: "Diuretics are
a mainstay of therapy in dogs with heart failure. In dogs with advanced
heart failure, moderate to high doses of loop diuretics such as furosemide
are used with diminishing effects as profound activation of neuroendocrine
systems promote signs of congestive heart failure. The loop diuretic
torsemide has several characteristics that make it suitable for treatment of
advanced heart failure including longer half-life, increased potency of
diuretic action, and anti-aldosterone effects. ... This case series
describes 3 dogs [including a 12 year-old
cavalier King Charles
spaniel
] with advanced heart disease that despite treatment with
multiple cardiac medications and moderate to high doses of furosemide
experienced frequently recurring episodes of CHF. ... In each dog,
replacement of furosemide with a torsemide dose, in terms of mg/kg, at
one-tenth to one-thirteenth of the daily furosemide dose were associated
with apparent resolution of CHF for relatively long durations of time. We
speculate that when switching to torsemide, restoration of diuretic response
was the most likely cause of this observation. In these and other cases
managed by the authors, pet owners report notable increases in their dog's
diuresis and water consumption following institution of torsemide. In a
small prospective blinded cross-over study,13 dogs with heart failure
experienced significantly higher serum albumin and significantly lower urine
specific gravity when receiving torsemide as compared to furosemide,
suggesting that torsemide is associated with a relatively greater diuretic
response. ... Torsemide's safety and superior efficacy have previously been
established in human patients with CHF. ... The restoration of diuretic
responsiveness and the accompanying volume depletion that follows torsemide
administration might increase risk for renal insufficiency, and care should
be taken to limit or reduce administration of concurrent diuretics such as
hydrochlorothiazide and to closely monitor renal function when administering
torsemide. The authors also recommend that owners of dogs receiving
torsemide closely monitor their dog's urine production, water consumption,
and appetite. ... Torsemide has several attractive pharmacologic properties
that might aid in the long-term treatment of canine heart disease. Clinical
guidelines or recommendations involving torsemide should follow from
prospective clinical trials demonstrating the long-term safety and potential
superiority of torsemide over furosemide and other commonly used diuretics."
Distribution of syringomyelia along
the entire spinal cord in clinically
affected
Cavalier King Charles Spaniels
Shenja
Loderstedt, Livia Benigni, Kate Chandler, Jacqueline M. Cardwell, Clare
Rusbridge, Christopher R. Lamb, Holger A. Volk. Vet J Dec 2011;190:359-363.
Quote: "The objective of the present study was to define the anatomic
distribution of SM in
CKCS
clinically affected by CM/SM.
Our hypotheses were that in dogs with SM, (1)SM is present at multiple
locations throughout the whole spinal cord; (2) the prevalence of SM is
greatest in the cervical spine versus other regions; (3) the presence of SM
in the cervical spinal cord is associated with the presence of SM in further
caudal spinal cord regions; (4) the maximal syrinx size in each patient is
in the cervical spine, and (5) there is a positive association between
patient age and total syrinx size. ... 49  dogs were included in the present
study. The median age of the dogs included in the study was 5 years
(1.2-10.8 years). CM was present in all patients. ... All dogs in the
present study were clinically affected. ... However, in our study SM was
absent in 25% of dogs with clinical signs. ... There was no evidence of SM
on MRI in 12/49 (25%) dogs. In all dogs with MRI evidence of SM (37/49;
75%), SM was present within the C1-C4 region (Figs. 2 and 3). Of those dogs
with SM within C1-C4 region, 76% (28/37) also had SM within the C5-T1 and/
or T2-L2 regions, but only 49% (18/37) had SM within the L3-L7 region. ...
The results of our investigation show that imaging only the cervical spine
in clinically affected CKCSs is likely to underestimate the total syrinx
size and the anatomical distribution of SM. The presence of cervical SM in
all dogs with MRI evidence of SM could however justify the restricted
imaging under screening purposes. ... The results of our study showed syrinx
formation in all regions of the spinal cord with no significant differences
of Sx between the cervical, cervicothoracic and thoracolumbar regions, but
significantly smaller Sx in the caudolumbar spinal region. ... In our study
Smax was most often seen within the C1-C4 region and, interestingly, also
over T2-L2 vertebral bodies. ... We found that the severity of SM was
positively correlated with patient age. This is consistent with previous
studies indicating that
CKCS
with SM were significantly
older than dogs without SM (Couturier et al., 2008). It seems likely
therefore, that SM is a progressive disease in dogs. ... Conclusions: There
is a very high potential for
CKCS
with clinical signs of
CM/SM to develop SM in more than one spinal cord region. Diagnostic imaging
limited to the cervical spine in clinically affected
CKCS
is likely to underestimate the degree and severity of SM. It can be
hypothesised that SM has a progressive nature in
CKCS
which requires further characterisation."
Can breeding strategies modify or eliminate the
syringomyelia phenotype?
Colin J. Driver, Holger A. Volk. Vet Rec; Dec
2011;169:679-680. Quote: "Breeding strategies have existed for some time to
limit the inheritance of common canine breed-specific diseases such as deafness
in dalmatians, glaucoma in flat-coated retrievers and hip dysplasia in labrador
retrievers. Progress in the control of these diseases relies on a greater
understanding of their mode of inheritance (Wood and others 2004). Since the
onset of using MRI in dogs in the late 1990s, the spinal cord disease
syringomyelia has been reported to commonly affect several small breed dogs,
notably the
Cavalier King Charles spaniel (CKCS)
and more
recently the Griffon Bruxellois (Rusbridge 1997, Rusbridge and others 2009). In
CKCS
, Chiari-like malformations of the skull base and its
content are ubiquitous and are the most prevalent predisposing cause for
syringomyelia (Rusbridge and others 2006, Cerda-Gonzalez and others 2009).
Chiari-like malformations and syringomyelia can be painful conditions. In the
case of syringomyelia, pain is related to the formation of asymmetrical
cavitations in the dorsal horn of the spinal cord (Rusbridge and others 2007).
The severity of the mismatch between the brain and skull that typifies
Chiari-like malformations is associated with the presence and severity of
syringomyelia (Driver and others 2010a). For some years a hereditary basis for
syringomyelia has been suggested in
CKCS
(Rusbridge and Knowler
2003). However, there had been limited research to suggest a mode of inheritance
for the disease. On this basis, a 'common sense' approach to interim breeding
guidelines was established in 2006 at an international
Cavalier
Club round table (Cappello and Rusbridge 2007), which is still used. The scheme
hoped to limit symptomatic syringomyelia while not affecting genetic diversity.
It was recommended that symptomatic dogs and young (less than two years)
asymptomatic dogs with syringomyelia were not used for breeding."
RETURN TO TOP
2012
Morphometric features of the craniocervical junction region in dogs with
suspected Chiari-like malformation determined by combined use of magnetic
resonance imaging and computed tomography
. Dominic J. Marino, Catherine
A. Loughin, Curtis W. Dewey, Leonard J. Marino, Joseph J. Sackman, Martin L.
Lesser, Meredith B. Akerman. AJVR. Jan. 2012;73(1):105-111. Quote:
"Objective: To objectively describe morphometric features of the
craniocervical junction region of
Cavalier King Charles Spaniels
(CKCSs)
and non-CKCS dogs with suspected Chiari-like malformation
(CLM) and identify associations between these features and the presence of
other malformations in this region. Animals:
216 CKCSs
and
58 non-CKCS dogs. Procedures: Magnetic resonance and computed tomographic
images of the head and craniocervical junction region of patients evaluated
because of suspected CLM were assessed for cerebellar compression (CC),
ventral spinal cord compression at the C1-C2 articulation (medullary
kinking), and dorsal spinal cord compression at the C1-C2 articulation
(dorsal compression). A compression index was calculated for each of these 3
locations in each dog. Multiple logistic regression analysis was performed
to determine whether breed (CKCS vs non-CKCS) and compression index values
were associated with the presence of other craniocervical junction
abnormalities. Results: All 274 dogs had CC; medullary kinking was
identified in 187 (68.2%) and dorsal compression was identified in 104
(38.0%). Atlantooccipital overlapping (AOO) was identified in 76 (27.7%)
dogs. Breed of dog (
CKCS
vs non-CKCS) and value of CC index
were the only significant predictors of AOO. The
CKCSs
had
an almost 5-fold decrease in risk of AOO, compared with the non-CKCS dogs,
and the risk of AOO nearly doubled for every 10% increase in CC index.
Conclusions and Clinical Relevance: The anatomic abnormality responsible for
CC was AOO in a substantial percentage of dogs suspected to have CLM. The CC
index value may be used to help differentiate subtypes of craniocervical
junction abnormalities in dogs."
Syringosubarachnoid shunt
as a management
for syringohydromyelia in dog
s.
L. Motta, G. C. Skerritt. J.Sm.An.Prac. Apr.2012; 53(4):205-212. Quote:
"Objective: To evaluate retrospectively the efficacy of syringosubarachnoid
shunt for the management of syringohydromyelia/syringomyelia. (The aim of
the surgical procedures would be to decompress the neural tissue, to
re-establish CSF flow and so decrease the syrinx size. In consequence, there
may be reduction of neuropathic pain and spinal cord function may be
promoted, providing that there has not been significant damage to the dorsal
grey column and/or spinothalamic tracts.) (The S-S shunting drains the
syrinx fluid into the subarachnoid space where the usual CSF circulation and
absorption mechanisms exist. This reduces the syrinx size and eases the
clinical signs associated with SHM/SM.) Methods: Eleven dogs (
cavalier King Charles spaniels
and 2 Yorkshire terriers) diagnosed
with syringohydromyelia/syringomyelia by magnetic resonance imaging
associated with Chiari-like malformation underwent placement of a
syringosubarachnoid shunt at the cervical (nine dogs) or lumbar (two dogs)
spinal cord. In one dog, a suboccipital decompression (foramen magnum
decompression) was performed 4 months before inserting a syringosubarachnoid
shunt (A silicone veterinary ocular lavage catheter by Smiths Medical was
used to create the shunt.) (In nine cases, this was carried out at C3-C4 and
in the remaining two cases at L1-L2). All dogs were evaluated neurologically
a few hours after surgery, 2 weeks and 6 months postoperatively.
Retrospectively, cases were assigned a preoperative and postoperative pain
score. Results: There were no intra- or peri-operative complications. One
dog (9%) was euthanased 5 weeks after surgery. Progressive neurological
improvement was observed in nine dogs (81·8%) 2 weeks and 6 months
postoperatively. No clinical improvement was seen in another dog (9%). One
dog (9%) had replacement of the syringosubarachnoid shunt. Seven dogs
(63·6%) were still alive 1 to 4 years (mean, 2·6 years) after surgery.
Clinical Significance: Placement of a syringosubarachnoid shunt in the
presence of a sufficiently large syrinx appears to be beneficial in dogs
with Chiari-like malformation and associated syringohydromyelia/syringomyelia.
(This small retrospective clinical study showed that S-S shunting is a safe
and relatively effective surgical technique that may improve the
neurological signs and the quality of life of dogs affected by CM and
associated SHM/SM. Postoperative complications or lack of clinical
improvement may occur in a small number of cases and a secondary surgery may
be needed. This study also suggests that the S-S shunt may lead to a
satisfactory outcome in dogs where the FMD technique has failed. Comparisons
between different surgical techniques are needed to create objective
criteria that may suggest which procedure will produce the best surgical
results.)"
Increase in Cerebellar Volume in
Cavalier King Charles
Spaniels
with Chiari-like Malformation and Its Role in the
Development of Syringomyelia
. Thomas A. Shaw, Imelda M. McGonnell,
Colin J. Driver, Clare Rusbridge, Holger A. Volk. PLoS ONE; April 2012;
7(4):e33660.
Quote: "Previous research in
Cavalier King Charles Spaniels
(CKCS)
has found that Chiari-like malformation and
syringomyelia (CM/SM) are associated with a volume mismatch between the
caudal cranial fossa (CCF) and the brain parenchyma contained within.
The objectives of this study were to i) compare cerebellar volume in
CKCS
(a "high risk' group which frequently develops
CM/SM), small breed dogs (medium risk - occasionally develop CM/SM), and
Labradors (low risk - CM/SM not reported); ii) evaluate a possible
association between increased cerebellar volume and CM/SM in
CKCS
; iii) investigate the relationship between increased
cerebellar volume and crowding of the cerebellum in the caudal part of
the CCF (i.e. the region of the foramen magnum). Volumes of
three-dimensional, magnetic resonance imaging derived models of the CCF
and cerebellum were obtained from
75 CKCS
, 44 small
breed dogs, and 31 Labradors. As SM is thought to be a late onset
disease process, two subgroups were formed for comparison: 18
CKCS
younger than 2 years with SM (CM/SM group) and 13 CKCS
older than 5 years without SM (CM group). Relative cerebellar volume was
defined as the volume of the cerebellum divided by the total volume of
brain parenchyma. ... Our results show that the cerebellum is
proportionately larger in
CKCS
(and a similar brainstem volume) when
compared to Labradors and small breed dogs and also larger in young
CKCS
with CM and SM than in older
CKCS
with CM alone. ... Furthermore, the degree of cerebellar crowding in the
caudal CCF is correlated with increased volume of the cerebellum in
CKCS
and this is not seen in small breed dogs or
Labradors. These findings have implications for the understanding of the
pathological mechanisms of CM/SM, and support the hypothesis that it is
a multifactorial disease process governed by increased cerebellar volume
and failure of the CCF to reach a commensurate size.  ... In this study we found that
CKCS
under the age
of 2 with SM (the CM/SM group) have an increased cerebellar volume when
compared to
CKCS
over the age of 5 without SM.
... In
CKCS
there is an
association between increased cerebellar volume and SM. These findings
have implications for the understanding of the pathological mechanisms
of CM/SM, and support the hypothesis that it is a multifactorial disease
process governed by increased cerebellar volume and failure of the CCF
to reach a commensurate size."
Effect of brachycephalic, mesaticephalic, and
dolichocephalic head conformations on olfactory bulb
angle and orientation
in dogs as determined by use of in vivo magnetic resonance imaging
Aseel K. Hussein, Martin Sullivan, Jacques Penderis. Am.J.Vety.Res. July
2012; 73(7):946-951. Quote: "Objective: To determine the effect of head
conformation (brachycephalic, mesaticephalic, and dolichocephalic) on
olfactory bulb angle and orientation in dogs by use of in vivo MRI. Animals:
40 client-owned dogs [including
11 cavalier King Charles spaniels
] undergoing MRI for diagnosis of conditions that did not
affect skull conformation or olfactory bulb anatomy. Procedures: For each
dog, 2 head conformation indices were calculated. Olfactory bulb angle and
an index of olfactory bulb orientation relative to the rest of the CNS were
determined by use of measurements obtained from sagittal T2-weighted MRI
images. Results: A significant negative correlation was found between
olfactory bulb angle and values of both head conformation indices. Ventral
orientation of olfactory bulbs was significantly correlated with high head
conformation index values (ie, brachycephalic head conformation).
Conclusions and Clinical Relevance: Low olfactory bulb angles and ventral
olfactory bulb orientations were associated with brachycephalia. Positioning
of the olfactory bulbs, cribriform plate, and ethmoid turbinates was
related. Indices of olfactory bulb angle and orientation may be useful for
identification of dogs with extremely brachycephalic head conformations.
Such information may be used by breeders to reduce the incidence or severity
of brachycephalic-associated diseases."
Distribution of substance P
and
calcitonin gene-related peptide in the spinal cord of
Cavalier King
Charles Spaniels
affected by symptomatic syringomyelia
. Hilary
Zhaoxu Hu, Clare Rusbridge, Fernando Constantino-Casas, Nick Jeffery.
Research in Vet Sci;
Aug 2012; 93(1):318-320. Quote: "The
causes of clinical signs associated with syringomyelia in the
Cavalier King Charles Spaniel (CKCS)
are incompletely understood.
In this study we compared expression of two pain-related neuropeptides:
substance P (SP) and calcitonin gene related peptide (CGRP), in the spinal
cord dorsal horn of normal dogs with that in
CKCS
with and
without clinical signs of syringomyelia. There was a decrease in expression
of both peptides in
CKCS
with 'symptomatic' syringomyelia
that was also associated with significant asymmetry in SP-I and similar,
though non-significant, asymmetry in CGRP-I compared with other groups. ...

This current study provides evidence to suggest that
the disruption of the dorsal horn structure is a significant event in the
production of clinical signs in
CKCS
. The spinal cord
dorsal horn in symptomatic
CKCS
is significantly more
asymmetric than that of control animals, whereas the asymptomatic
CKCS
have changes that are midway between control and symptomatic
CKCS
. This suggests the possibility that progression from
mild to severe asymmetry in
CKCS
is associated with
development of clinical signs; however such a conclusion cannot be
definitively supported by this study because of the cross sectional nature
of the data collected."
Comparison of
the Relative
Occipital Bone Volume Between
Cavalier King Charles
Spaniels
with and Without Syringohydromyelia and French Bulldogs
M.J. Schmidt, M. Kramer, N. Ondreka. Sept. 2012. Vet. Radiology & Ultrasound.
53(5):540-544. Quote: "Our aim was to determine the relative volume of the occipital bone
of
Cavalier King Charles spaniels
with and without
syringohydromyelia and normal French bulldogs [as the weight of this
breed met the range of the
Cavalier King Charles spaniels
(8-12 kg)] to reappraise the role of a
possible insufficiency of the paraxial mesoderm in the pathogenesis of the
caudal occipital malformation syndrome. Analysis of the occipital bone
volume of 43 dogs [
30 CKCSs
] based on computed tomography datasets was performed.
Volume was determined by means of three-dimensional models. Using manual
segmentation of the occipital bone in sagittal, transverse, and dorsal
images, the volume of the occipital bone and the rest of the skull was
calculated. The absolute occipital bone volume was put in relation to the
total skull volume, the occipital bone index. For the
[15] Cavalier King
Charles spaniels
without syringomyelia, the median occipital bone
index was 0.0681; for
[15] Cavalier King Charles spaniels
with
syringomyelia, it was 0.0646 and for [13] French bulldogs, it was 0.0676. There
was no global difference of the occipital bone index between examined groups
(P = 0.4331). A reduced volume of the occipital bone was not found in
Cavalier King Charles spaniels
in general in comparison to
French bulldogs, or in
Cavalier King Charles spaniels
with
syringomyelia compared to
Cavalier King Charles spaniels
without syringomyelia. These results do not support occipital hypoplasia as
a cause for syringomyelia development, challenging the paraxial mesoderm
insufficiency theory. This also suggests that the term Chiari-like
malformation, a term derived from human studies, is not appropriate in the
Cavalier King Charles spaniel
."
Questionnaire-based
behaviour analysis
of
Cavalier King Charles spaniels
with neuropathic pain due to Chiari-like malformation and syringomyelia.
Lynda Rutherford, Annette Wessmann , Clare Rusbridge , Imelda M. McGonnell,
Siobhan Abeyesinghe , Charlotte Burn , Holger A. Volk. Vet.J.
194(3):294-298. Quote: "Chiari-like
malformation (CM)/syringomyelia (SM) is a disease complex recognised in
Cavalier King Charles spaniels (CKCSs)
that can lead to
neuropathic pain (NeP). In humans, NeP is associated with anxiety,
depression and reduced quality of life (QoL). In this study, databases of
three specialist veterinary centres were searched and
CKCS
breed societies and health forums were contacted to identify
CKCS
with an imaging diagnosis of CM/SM. Owners completed questionnaires on
behaviour, signalment, general health status, NeP and QoL. Data were
analysed from 122 dogs out of 564 questionnaires completed, after incomplete
questionnaires and data from dogs that had other potentially debilitating
disease processes were excluded. ... Section 2: Questions asked in this
section aimed to provide an insight into the dog's general behaviour, any
clinical manifestations of CM/SM and owner perceived QoL. Respondents were
asked to what degree they had observed the following NeP signs of CM/SM in
their dog on a semantic 5-point differential-type rating scale (...
behaviour is exhibited 0 = never, 1 = seldom, 2 = sometimes, 3 = usually, 4
= always): (1) persistent, compulsive scratching with no underlying skin
disease; (2) facial rubbing; (3) hypersensitivity to touch; (4) unexplained
yelping; (5) reluctance to lift head; (6) reluctance to bend neck to eat; or
(7) reluctance or pain when defaecating. Scores were averaged across these
clinical signs to determine an individual NeP severity score (NeP score).
The same scale was also used to establish a locomotory score and a score for
sleeping/resting. To quantify owner perceived QoL, owners were asked to rate
their dog's overall QoL on a fixed scale as follows: 1 = could not be
better; 2 = good; 3 = fairly good; 4 = neither good nor bad, 5 = fairly
poor; 6 = poor; 7 = could not be worse or 8 = do not know. Section 3: ...
This section had 11 broad categories: 'stranger-directed' aggression;
'owner-directed' aggression; 'stranger-directed' fear; non-social fear;
'dog-directed' fear; 'separation-related' behaviour; attachment or attention
seeking behaviour; trainability; chasing behaviour; excitability; and pain
sensitivity. The aforementioned sliding scale from 0 to 4 was used to
quantify responses. ... NeP severity score was significantly and positively
correlated with 'stranger-directed' fear (rS = 0.28), non-social fear (rS =
0.34), 'separation-related' behaviour (rS = 0.38), attachment behaviour (rS
= 0.24), excitability (rS = 0.21) and proxy for pain sensation (rS = 0.29).
Increased NeP was also significantly associated with decreased QoL (rS =
0.47), ability to settle (rS = 0.26) and willingness to exercise (rS =
0.50). Severity of NeP was positively associated with certain
fear-associated behaviour and with decreased owner-perceived QoL. Thus,
neurobehavioural changes should be considered in the management of NeP in
CKCS
with CM/SM."
Resolution of life-threatening dysphagia
caused by caudal occipital
malformation syndrome following foramen magnum decompressive surgery
KJ Graham, AP Black, PH Brain. Australian Vet,J. Aug 2012;90(8):297-300.
Quote: "A
Cavalier King Charles Spaniel
was presented with
acute onset, life-threatening dysphagia suspected to be secondary to medulla
oblongata compression caused by caudal occipital malformation syndrome. The
patient required urgent tracheostomy tube placement to remain stable and was
subsequently cured of the presenting neurological deficits by foramen magnum
decompressive surgery. Neurogenic dysphagia is a relatively common
presenting sign in human Chiari malformation syndromes, but has not been
described as a major clinical sign in veterinary patients. Caudal occipital
malformation syndrome should be included in the differential diagnosis list
for susceptible breeds presenting with dysphagia. Early recognition favours
expeditious surgical intervention and a positive outcome in human patients,
and this may also be the case in veterinary patients."
Assessment of
the effects of adjunctive gabapentin
on postoperative pain after
intervertebral disc surgery in dogs
. Sonja A. Aghighi, Andrea Tipold,
Marion Piechotta, Piotr Lewczuk, Sabine B.R. Kastne. Veterinary Anaesthesia
and Analgesia. Aug 2012. Quote: "Objective: To assess the effect of
adjunctive gabapentin (GBP) on pain after thoracolumbar intervertebral disc
surgery in dogs. Study design  Prospective, randomized, controlled,
clinical, 'blinded' trial. Animals: Sixty-three client owned dogs undergoing
hemilaminectomy. Methods: Dogs were assigned to two treatment groups. The
GBP group received gabapentin 10 mg kg−1 orally every 12 hours starting
before anaesthesia; the placebo (P) group received empty gelatin capsules.
Background analgesia was initiated with intravenous levomethadone 0.6 mg
kg−1 (as the combination 'L-Polamivet) at anaesthesia induction, followed by
a fentanyl patch and levomethadone 0.2 mg kg−1 subcutaneously every 8 hours
for 24 hours. Pain was assessed by the short form of the Glasgow Composite
Measure Pain Score (CMPS-SF) without the gait category, and by a Visual
Analogue Scale (VAS). Serum GBP concentrations and cortisol concentrations
were measured. Statistical analyses utilized chi square test, Kolmogorov-Smirnov
test, two-way analysis of variances for repeated measurements, Wilcoxon test
and Friedmann test as relevant. Correlations were tested by Spearman's and
Pearson's correlation coefficient. p < 0.05 was considered significant.
Results: Median CMPS-SF was lower in group GBP than in group P on days 0.5,
1, 4 and 5. However, CMPS-SF and VAS were not significantly different
between groups. Both pain scores decreased significantly over time. Cortisol
concentrations were not significantly different between groups. Minimum
serum concentrations of GBP fell below the detection limit of 1 μg mL−1 in 6
of 29 and 7 of 28 dogs at 24 and 72 hours, respectively. Conclusions and
clinical relevance: 10 mg kg−1 GBP orally twice a day did not result in a
detectable reduction in pain behaviour compared to background opioid
analgesia alone, although a trend to lower pain levels (p < 0.1) was
present. Further studies are needed to determine if this is related to
effective background analgesia or an ineffective dose of GBP."
Malformation Chiari-Like : l'investigation d'une maladie complexe par
l'utilisation d'un modèle canin.
Philippe Lemay, Zoha Kibar. Thesis.
Univ. Montreal. Aug. 2012. Quote: "Chiari I malformation (CMI) represents a
common congenital abnormality of the craniocerebral junction with an
estimated incidence of 1 in 1280. CMI is characterized by a descent of the
cerebellar tonsils into the foramen magnum, often in association with
syringomyelia. The developmental defect in CMI is thought to be the result
of an underdeveloped occipital bone and small posterior fossa. The etiology
of CMI is thought to be multifactorial involving genetic factors. CMI in
humans is similar to a condition in the dog called Chiari-like malformation
(CM) that is particularly common in the Griffon Bruxellois (GB) breeds. A
genome wide association study on a 56 GB cohort followed by a fine mapping
in a 217 GB cohort have identified a locus on chromosome 2 that was strongly
associated with CM (22 SNPs, P value= 7 x 10-8). Haploview analysis of this
locus identified a haplotype of 1.9 Mb that was more frequent in
non-affected dogs. A second genome wide association study in a 113 GB cohort
lead to the identification of another locus on chromosome 13 that was
strongly associated with CM (25 SNPs , P value= 3 x 10-7). Analysis of this
region identified a 4Mb haplotype that was more frequent in non-affected
dogs. Our study constitutes the first essential step towards identification
of the causative genes in CM. Our study provides an entry point for better
understanding of the molecular genetic mechanisms underlying the
pathogenesis of human CMI."
Volume reduction of
the jugular foramina
in
Cavalier King Charles Spaniels
with syringomyelia.
Martin J Schmidt, Nele Ondreka, Christoph Rummel,
Holger Volk, Maren Sauerbrey and Martin Kramer. Vety.Research. Sept. 2012;
8:158. Quote: "Background: Understanding the pathogenesis of the chiari-like
malformation in the
Cavalier King Charles Spaniel (CKCS)
is
incomplete, and current hypotheses do not fully explain the development of
syringomyelia (SM) in the spinal cords of affected dogs. This study
investigates an unconventional pathogenetic theory for the development of
cerebrospinal fluid (CSF) pressure waves in the subarachnoid space in
CKCS
with SM, by analogy with human diseases. In children
with achondroplasia the shortening of the skull base can lead to a narrowing
of the jugular foramina (JF) between the cranial base synchondroses. This in
turn has been reported to cause a congestion of the major venous outflow
tracts of the skull and consequently to an increase in the intracranial
pressure (ICP). Amongst brachycephalic dog breeds the
CKCS
has been identified as having an extremely short and wide braincase. A
stenosis of the JF and a consequential vascular compromise in this opening
could contribute to venous hypertension, raising ICP and causing CSF jets in
the spinal subarachnoid space of the
CKCS
. In this study,
JF volumes in
CKCSs
with and without SM were compared to
assess a possible role of this pathologic mechanism in the development of SM
in this breed. Results: Computed tomography (CT) scans of
40 CKCSs
> 4 years of age were used to create three-dimensional (3D) models of the
skull and the JF. Weight matched groups (7--10 kg) of
20 CKCSs with
SM and 20 CKCSs without SM
were compared.
CKCSs
without SM presented significantly larger JF -volumes (median left JF:
0.0633 cm3; median right JF: 0.0703 cm3; p < 0.0001) when compared with
CKCSs
with SM (median left JF: 0.0382 cm3; median right JF:
0.0434 cm3; p < 0.0001). There was no significant difference between the
left and right JF within each group. Bland-Altman analysis revealed
excellent reproducibility of all volume measurements. Conclusion: A stenosis
of the JF and consecutive venous congestion may explain the aetiology of CSF
pressure waves in the subarachnoid space, independent of cerebellar
herniation, as an additional pathogenetic factor for the development of SM
in this breed."
Cervicothoracic
syringohydromyelia associated with a prosencephalic mass in a dog
. D.
Szabo, T. C. Saveraid, S. Rodenas. J.Sm.Anim.Prac. Oct. 2012;53(10):613-617.
Quote: "A five-year-old, female, neutered boxer, with neuroanatomical signs
consistent with a C1-C5 myelopathy, was diagnosed with a prosencephalic mass
and associated severe cervicothoracic syringohydromyelia. After treatment
with corticosteroids and lomustine, neurological examination was normal.
Imaging repeated three months later showed significant reduction in both the
size of the mass and the syringohydromyelia. To the authors' knowledge, this
is the first reported case of a dog with syringohydromyelia secondary to a
rostral brain mass that had clinical signs on presentation solely due to the
syrinx, and the first reported case in a dog of partial resolution of
syringohydromyelia after treatment solely with chemotherapy."
Chiari-like malformation:
A substantive health and welfare problem in the
Cavalier King
Charles Spaniel
Jacques Penderis. Vety.J. Feb.
2013;195(2):133-134.
Quote: "... In particular, it has been suggested that selection for a
specific head phenotype has inadvertently resulted in Chiari-like
malformation in this breed. Examination of the genetics of Chiari-like
malformation in the
CKCS
indicates that this may be an
oversimplification of the problem, as the disease is likely to represent a
complex oligogenic trait with moderately high heritability (
Lewis
et al., 2010
). Irrespective of the cause, Chiari-like malformation is a
substantive problem in the breed, estimated to affect around 95% of
CKCS
Dewey
and Rusbridge, 2008
). Although many cases are clinically silent,
characteristic morphological changes are present in the brains of affected
animals (
Carrera et al., 2009
).
... The poor reputation that the breed endures is, in part, unjustified.
Instead of shying away from publicity, many
CKCS
breed
clubs have worked hard to raise public awareness of health issues in the
breed and raise funds to support clinical research into disease prevention.
This proactive attitude and willingness to engage with researchers has
already delivered positive results, with the release of a genetic test for
Episodic Falling
in
CKCS
by the Animal Health Trust (UK) in April, 2011 (
Forman
et al., 2012
) and the development of a joint Kennel Club and British
Veterinary Association screening programme for Chiari- like malformation in
CKCS
in the UK. Instead of criticising
CKCS
breeders, we should be supportive of their efforts to understand
breed-related problems and help them work to improve the health and welfare
of the breed. ... The high prevalence of Chiari-like malformation in the breed and the
confirmation that brain morphology is directly influenced by head phenotype
Hussein et al., 2012
), suggests that Chiari-like malformation in the
CKCS
is likely to be the inadvertent consequence of
misguided breeder selection to emphasise certain cranial features deemed to
be desirable. The high breed prevalence of Chiari-like malformation
(estimated at 95%) points to limited genetic diversity within the
CKCS
, resulting in major difficulties if breeding away from
conformations associated with Chiari-like malformation is attempted in the
future."
Long-term outcome of
Cavalier King Charles Spaniels
with
clinical signs associated with Chiari-like malformation and syringomyelia
I. N. Plessas, C. Rusbridge, C. J. Driver, K. E. Chandler, A. Craig, I. M.
McGonnell, D. C. Brodbelt, H. A. Volk. Vet.Rec.Oct. 2012;doi:
10.1136/vr.100449. Quote: "The disease complex Chiari-like malformation (CM)
and syringomyelia (SM) has been associated with the development of
neuropathic pain (NeP), and commonly affects
Cavalier King Charles
spaniels (CKCS)
. It is not yet fully understood how CM/SM causes
NeP. However, histopathological studies of SM in
CKCS
have
found that dogs which had expressed signs of NeP suffered an asymmetrical
syrinx with profound alteration of the structure of the dorsal horn laminae,
and had reduced expression of the pain-related neuropeptides substance P,
and calcitonin gene-related peptide (
Hu and others 2012a
).This prospective
cohort study followed
48 CKCSs
[between ages 1 year and 13
years] with
CM and/or SM [Nine of the 48 dogs had CM only]
and clinical signs suggestive of NeP for a period of 39 (±14.3) months from
diagnosis. At the end of the study, 36 dogs were still alive; five dogs died
of an unrelated
or unknown cause, and seven were euthanased due to severe
clinical signs suggestive of NeP. During the follow-up period, the clinical
signs of scratching, facial rubbing behaviour, vocalisation and exercise
ability were evaluated. Nine out of 48 dogs stopped scratching (P<0.001),
but there was no statistically significant change in the number of dogs
exhibiting exercise intolerance, vocalisation or facial rubbing behaviour.
The overall severity of clinical signs based on a visual analogue scale
(VAS) (0 mm: no clinical signs
100 mm: severe clinical signs) increased
(from median 75 mm (interquartile ranges (IQR) 68-84) to 84 mm (IQR
71.5-91), P<0.001). A quarter of the dogs were static or improved. In
general, the majority of the owners felt that the quality of life of their
dogs was acceptable. Medical treatments received were gabapentin or
pregabalin and/or intermittently, carprofen. The owner's perception of their
animal's progress, and progress based on VAS, had strong positive
correlation (Spearman's rank correlation (sr) 0.74, P<0.001). Overall, this
study suggests that clinical signs suggestive of NeP progress in
three-quarters of
CKCSs
with CM and/or SM. ... Traditionally,
clinical signs suggestive of NeP in CKCS have been associated with CM and
SM, but from our study, we found that CM only may contribute to these signs,
too. ... Finally, it is important to mention that this study is documenting
the progression of a specific set of clinical signs in a group of dogs with
CM and/or SM, and not the progression of the disease itself."
Changes over time in craniocerebral morphology and syringomyelia in
cavalier King Charles spaniels
with Chiari-like malformation.
Colin J Driver, Luisa De Risio, Sarah Hamilton, Clare Rusbridge, Ruth
Dennis, Imelda M McGonnell, Holger A Volk. BMC Vet. Research Nov. 2012,
8:215. Quote:
"Background: Chiari-like malformation (CM) and syringomyelia is a
neurological disease complex with high prevalence in
cavalier King
Charles spaniels (CKCS)
. The natural progression of this disease
with time has not been described. The objectives of this study were to i)
determine if syringomyelia progresses with time ii) determine if features of
craniocrebral morphology previously associated with CM are progressive
(including caudal cranial fossa volume, caudal cranial fossa parenchymal
volume, ventricular dimensions, height of the foramen magnum and degree of
cerebellar herniation). A retrospective morphometric analysis was undertaken
in
12 CKCS
with CM for which repeat magnetic resonance
images were available without surgical intervention. Results: The maximal
syrinx width, height of the foramen magnum, length of cerebellar herniation
and caudal cranial fossa volume increased over time. Ventricular and caudal
fossa parenchymal volumes were not significantly different between scans.
Conclusions: The results of this study suggest that syringomyelia progresses
with time. Increased caudal cranial fossa volume may be associated with
active resorption of the supraoccipital bone, which has previously been
found in histology specimens from adult
CKCS
. We
hypothesise that active resorption of the supraoccipital bone occurs due to
pressure from the cerebellum. These findings have important implications for
our understanding of the pathogenesis and variable natural clinical
progression of CM and syringomyelia in
CKCS
."
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2013
Caudal cranial fossa partitioning in
Cavalier King Charles spaniels
T. A. Shaw, I. M. McGonnell, C. J. Driver, C. Rusbridge, H. A. Volk.
Vety.Rec. Feb. 2013. Quote: "Here, we report that the morphology of the
canine skull is affected by variation in hindbrain volume. Important
differences exist between
CKCS [cavalier King Charles spaniels
],
SB [small breeds] and LD [Labradors] that are pertinent to the pathological
mechanisms of CM/SM. ... A retrospective study of MRI scans of
CKCS
SB and LD was performed. ... We found that
CKCS
had a
relatively large pars rostralis [tentorium cerebelli] volume ... and
relatively small pars caudalis [occipital bones] volume ... when compared
with LD and SB ... . These findings suggest that in CKCS there is a
reduction in occipital skull volume and an increase in the volume bounded by
the tentorium cerebelli. Furthermore, pars caudalis volume was reduced in
the CM/SM group ... compared with CM group ..., which suggests an
association between reduced volume in the caudal part of the CCF and the
development of SM .... The pars media of the SB group ... was significantly
smaller than the LD ... and
CKCS
groups ... . Our results
also revealed important differences in the relationship between hindbrain
volume and CCF morphology... . These findings suggest that SB and LD
compensate for variations in hindbrain volume by modifying the growth of the
occipital skull, whereas in
CKCS
, occipital bone
development is insensitive to changes in hindbrain volume. We infer from
these results that increased hindbrain volume in
CKCS
causes the tentorium cerebelli to compensate by bulging in a rostral
direction. A similar phenomenon, an increase in the angle of the tentorium,
has been widely reported in humans with Chiari malformation I  ... .
The data support the hypothesis that CM/SM in
CKCS
is a
multifactorial disease process governed by the effects of increased
hindbrain volume and impaired occipital bone development. The present
authors recently reported that CM/SM is linked to increased cerebellar
volume (Shaw and others 2012). In view of this, the aetiopathogenesis [cause
and development] of CM/SM may equivocally be mediated by conditions
independently affecting the developing occipital bones and cerebellum, or by
dysregulation of a signaling mechanism coordinating the growth of the
developing hindbrain and occipital skull.
The association between
Chiari-like malformation, ventriculomegaly and seizures in
cavalier
King Charles spaniels.
C.J. Driver, K. Chandler, G. Walmsley,
N. Shihab, H.A. Volk. Vet.J. February 2013;195(2):235-237; doi:
10.1016/j.tvjl.2012.05.014
. Quote:
Cavalier King Charles
spaniels (CKCSs)
with Chiari-like malformation (CM) and associated
seizures are frequently diagnosed with idiopathic epilepsy. There could be
an association between ventriculomegaly (V) or caudal fossa overcrowding
(CCFP) and seizures. A retrospective case-control study was performed using
MRI to investigate the possible association between these morphological
abnormalities and seizures. Seizure semiology and, where possible,
electroencephalographic (EEG) abnormalities were documented.
Eighty-five CKCS
with CM were included, 27 with seizures. There was
no association between V or CCFP and seizures (P = 0.10 and 0.71,
respectively). Seizures were classified as having partial onset [meaning
that they occur in in one area of the brain, unlike generalized seizures
which typically affect nerve cells throughout the brain] in 61% of
individuals in the study population (95% CI 42.41-76.43%). Another cause of
recurrent seizures in
CKCS
(such as familial epilepsy) is
suspected, as previously reported.
Syringomyelia and Chiari Malformation in
Cavalier King Charles
Spaniels
- Magnetic Resonance Imaging, Pharmacological and Surgical
Treatment
. Andrzej Pomianowski, Zbigniew Adamiak. Bulletin of
Vet.Inst.Pulway. March 2013;57(1):131-133. Quote: "The aim of the study was
to describe images of syringomyelia and Chiari malformation in
Cavalier King Charles Spaniels
, produced by low field magnetic
resonance sequences, and to discuss the results of pharmacological and
surgical treatment performed in dogs with the disease. Nine
Cavalier
King Charles Spaniels
aged from 2 to 5 years, including seven
females and two males, with Chiari malformation and syringomyelia, which
were subjected to low-field magnetic resonance imaging (MRI) test, were
described. The results of MRI examinations were presented. The outcomes of
pharmacological therapy involving two dogs and surgical treatment of one dog
were also described. The applied treatments produced positive short-term
outcomes, and they eliminated the clinical symptoms of the disease."
Craniocervical
junction abnormalities in dogs
. C W Dewey, D J Marino, C A Loughin.
New Zealand Vet. J. April 2013;61(4):202-211. Quote: "Craniocervical
junction abnormality (CJA) is a term that encompasses a number of
developmental anatomical aberrations at the region of the caudal occiput and
first two cervical vertebrae. Chiari-like malformation appears to be the
most common CJA encountered in dogs, and there has been a tremendous amount
of clinical investigation into this disorder in recent years. Other
abnormalities in this region include atlanto-occipital overlap, dorsal
constriction at C1/C2 and atlantoaxial instability. This review article
presents an overview of the current understanding of CJA in dogs, as well as
medical and surgical treatment options available."
A Potential
Role for Substance P and Interleukin-6
in the Cerebrospinal Fluid of
Cavalier King Charles Spaniels
with Neuropathic Pain.
M.J. Schmidt, J. Roth, N. Ondreka, M. Kramer, and C. Rummel.
J.Vet.Intern.Med. May 2013; 27(3):530-535. Quote: "Background: Neuropathic pain can be a
clinical sign in
Cavalier King Charles Spaniels (CKCS)
with
syringomyelia.
The pathophysiology of this pain is not fully understood. Hypothesis:
Neuropathic pain in CKCS is a result of a euroinflammatory process. Animals:
Twenty-six client-owned dogs: 15 dogs with clinical signs of cervical
hyperesthesia (group 1), and 11 dogs without of clinical signs (group 2).
Methods: Dogs were examined by magnetic resonance imaging (MRI).
Interleukin-6, tumor necrosis factor alpha, and substance P were measured in
CSF and compared with morphological findings on MRI and clinical pain
scores. Results: All dogs without clinical signs had symmetrical
syringomyelia, whereas in the group with pain, 6 dogs had symmetrical and 9
dogs had asymmetrical syringomyelia. Pain and syringomyelia asymmetry were
correlated, and a strong association between pain and dorsal horn
involvement of syringomyelia was observed. There was no significant
difference between the mean width of the syringomyelia in dogs with or
without pain. The concentrations of interleukin-6 and substance P were
significantly higher in dogs with neuropathic pain. Tumor necrosis factor
alpha was not detected in either group. Concentrations of substance P were
significantly higher in dogs with asymmetrical syringomyelia or dorsal horn
involvement, whereas interleukin-6 concentrations were not significantly
different between groups. Conclusion: Release of interleukin-6 and substance
P may initiate proinflammatory effects leading to development of persistent
pain in
CKCSs
with syringomyelia."
Magnetic Resonance Imaging (MRI) Spinal Cord and
Canal Measurements in Normal Dogs
. S. Hecht, M. M. Huerta, R. B. Reed.
Anatomia Histologia Embryologia. March 2013. Quote: "The goal of this study
was to establish Magnetic resonance imaging (MRI) reference ranges for
spinal measurements in normal dogs. Forty dogs (1-10 kg, 11-20 kg, 21-30 kg,
> 30 kg; 10 dogs per category) underwent spinal MRI. Measurements were
performed on sagittal T2-W images at the level of the 4th thoracic vertebra
(T4), the 9th thoracic vertebra (T9) and the 3rd lumbar vertebra (L3).
Spinal canal diameter (mm) ranged from 6.07 ± 0.63 (1-10 kg) to 8.27 ± 1.15
(> 30 kg) at the level of T4; 6.55 ± 0.61 (1-10 kg) to 9.04 ± 1.26 (> 30 kg)
at the level of T9; and 6.80 (6.47-7.00; 1-10 kg) to 9.00 (7.90-9.73; > 30
kg) at the level of L3. There were significant differences (P < 0.05) in
spinal canal diameter between groups. Mean spinal cord diameter (mm) ranged
from 4.46 ± 0.51 (11-20 kg) to 4.70 ± 0.35 (1-10 kg) at the level of T4;
4.41 ± 0.50 (> 30 kg) to 4.85 ± 0.57 (1-10 kg) at the level of T9; and 4.52
± 0.51 (> 30 kg) to 5.14 ± 0.68 (1-10 kg) at the level of L3. There were no
significant differences in spinal cord diameter between groups. Spinal
cord-to-spinal canal ratio varied significantly, ranging from 0.51 ± 0.08 (>
30 kg at L3) to 0.78 (0.69-0.80; 1-10 kg at T4) (P < 0.05). These findings
are important when using MRI to evaluate patients with suspected diffuse
spinal cord disease."
Syringomyelia and Chiari Malformation in
Cavalier King Charles
Spaniels
- Magnetic Resonance Imaging, Pharmacological and Surgical
Treatment
Andrzej Pomianowski, Zbigniew Adamiak. Bulletin of Vet.
Institute in Pulawy. March 2013;57: 131-133. Quote: "Nine dogs [
all cavalier
King Charles spaniels
] with Chiari malformation and syringomyelia,
which were subjected to low-field magnetic resonance imaging (MRI) test,
were described. The results of MRI examinations were presented. The outcomes
of pharmacological therapy involving two dogs and surgical treatment of one
dog were also described. The applied treatments produced positive short-term
outcomes, and they eliminated the clinical symptoms of the disease. ... The
results of the study and published data indicate that magnetic resonance
imaging is essential for diagnosing Chiari-like malformations and
syringomyelia. Caudal cerebellar herniation was observed in all cases,
including the patients examined upon the owners' request to obtain a
certificate for breeding purposes. In this group of dogs, herniation was
found in all patients, but none of the owners reported any neurological
disorders. ... In the group of three dogs with neurological symptoms, two
owners decided to subject their animals to pharmacological treatment, and
one owner opted for surgery. In pharmacologically treated dogs, clinical
symptoms subsided during the observation period. According to the owner of
the surgically treated dog, the symptoms of the disease subsided after
treatment and the dog fully recovered. ... The results delivered by both
treatment models seem to be promising, albeit in a short-term perspective.
The owners of the studied animals broke off contacts with the clinics
performing the treatment, thus shortened the clinical observation period."
Venous sinus
volume in the caudal cranial fossa
in
Cavalier King Charles
spaniels
with syringomyelia.
Joe Fenn, Martin J. Schmidt,
Harriet Simpson, Colin J. Driver, Holger A. Volk. Vet.J. June 2013; doi:
10.1016/j.tvjl.2013.05.007 . Quote: "Syringomyelia
(SM) in
Cavalier King Charles spaniels (CKCS)
has a complex
pathophysiology. Recent studies support a relationship between altered
venous drainage and cerebrospinal fluid flow dynamics. The aim of this study
was to evaluate the relationship between venous sinus and parenchymal volume
within the caudal cranial fossa (CCF) in
CKCS
with SM (n =
22) and without SM (n = 12) using magnetic resonance venography (MRV). MRI
and MRV images were used to obtain volumetric calculations of CCF volume, as
well as the percentage of this volume occupied by parenchyma (CCFP%) and
venous sinuses (CCFV%). In
CKCS
with SM, CCFP% was
significantly higher, whilst CCFV% was significantly lower than in
CKCS
without SM. These results support a
role for reduced venous drainage and parenchymal 'overcrowding' of the CCF
in the pathophysiology of SM."
Assessment of cerebellar pulsation in dogs with and
without Chiari-like malformation and syringomyelia using cardiac-gated cine
magnetic resonance imaging.
C.J. Driver, V. Watts, A.C. Bunck, L.M. Van
Ham, H.A. Volk. Vet.J. June 2013. Quote: "Canine Chiari-like malformation
(CM) is characterised by herniation of part of the cerebellum through the
foramen magnum. In humans with Chiari type I malformation (CM-I), abnormal
pulsation of the cerebellum during the cardiac cycle has been documented and
is pivotal to theories for the pathogenesis of syringomyelia (SM). In this
retrospective study, cardiac-gated cine balanced fast field echo (bFEE)
magnetic resonance imaging (MRI) was used to assess pulsation of the brain
in dogs and to objectively measure the degree of cerebellar pulsation with
the neck in a flexed position. Overall,
17 Cavalier King Charles
Spaniels (CKCS) with CM, including eight with SM and nine without SM
were compared with six small breed control dogs. Linear regions of interest
were generated for the length of cerebellar herniation from each phase of
the cardiac cycle and the degree of cerebellar pulsation was subsequently
calculated. Age, bodyweight and angle of neck flexion were also compared.
CKCS
with CM and SM had significantly greater pulsation of
the cerebellum than control dogs (P = 0.003) and
CKCS
with
CM only (P = 0.031). There was no significant difference in age, bodyweight
and angle of neck flexion between the three groups. Cardiac-gated cine bFEE
MRI permitted the dynamic visualisation of cerebellar pulsation in dogs.
These findings support the current theories regarding the pathogenesis of SM
secondary to CM and further highlight the similarities between canine CM and
human CM-I."
Comparison of Closure Times for Cranial Base Synchondrose
s in
Mesaticephalic, Brachycephalic, and
Cavalier King Charles Spaniel
Dogs
Martin J. Schmidt, Holger Volk, Melanie Klingler, Klaus
Failing, Martin Kramer, Nele Ondreka. Vet.Radiology & Ultrasound. Sept.
2013;54(5):497-503.
Quote: "Premature closure of cranial base synchondroses has been proposed as
the mechanism for brachycephaly in dogs and caudal occipital malformation
syndrome (COMS) in
Cavalier King Charles Spaniels
. The
purpose of this retrospective study was to compare times of closure for
cranial base synchondroses in mesaticephalic, brachycephalic, and
Cavalier King Charles Spaniel
dogs. Cranial magnetic resonance
imaging studies were retrieved for client-owned dogs less than 18 months of
age. Breed, age, skull conformation, and the open or closed state of cranial
base synchondroses were independently recorded by two observers. For dogs
with a unanimous observer agreement, regression analysis was used to test
effects of age and gender on the open or closed status of synchondroses and
differences between groups. A total of 174 dogs were included in MRI
interpretations and 165 dogs were included in the regression analysis.
Statistically significant differences in closure time of the spheno-occipital
synchondrosis were identified between brachycephalic and mesaticephalic dogs
(P = 0.016),
Cavalier King Charles Spaniels
and
mesaticephalic dogs (P < 0.0001), and
Cavalier King Charles Spaniels
and brachycephalic dogs (P = 0.014). Findings from the current study
supported the theory that morphological changes leading to the skull
phenotype of the
Cavalier King Charles Spaniels
could be
due to an earlier closure of the spheno-occipital synchondrosis." See
also,
Retrospective analysis of the joint conclusion of synchondroses base of
the skull in dogs of various breeds with special consideration of
Cavalier King Charles Spaniels
Variations in Magnetic Resonance Venographic Anatomy of the Dorsal Dural
Venous Sinus System in 51 Dogs
. Joe Fenn, Richard Lam, Patrick J.
Kenny. Vet.Radiology&Ultrasound. June 2013. Quote: "Variations in
intracranial dural venous sinus anatomy have been widely reported in humans,
but there have been no studies reporting this in dogs. The purpose of this
retrospective study was to describe variations in magnetic resonance (MR)
venographic anatomy of the dorsal dural venous sinus system in a sample
population of dogs with structurally normal brains. Medical records were
searched for dogs with complete phase contrast, intracranial MR venograms
and a diagnosis of idiopathic epilepsy. Magnetic resonance venograms were
retrieved for each dog and characteristics of the dorsal dural sinuses,
symmetry of the transverse sinuses and other anatomic variations were
recorded. A total of 51 dogs were included [including
8 cavalier
King Charles spaniels
]. Transverse sinus asymmetry was present in
58.8% of the dogs, with transverse sinus hypoplasia seen in 39.2%, and
aplasia in 23.5% of dogs. For 70.6% of dogs, at least one anatomic variation
in the dorsal sagittal sinus was observed, including deviation from the
midline (33.3%) and collateral branches from either the dorsal sagittal
sinus or dorsal cerebral veins (54.9%). In 5 dogs (9.8%) a vessel was also
identified running from the proximal transverse sinus to the distal sigmoid
sinus, in a similar location to the occipital sinus previously reported in
children. Findings from this study indicated that, as in humans, anatomic
variations are common in the intracranial dural venous sinus system of dogs.
These anatomic variations should be taken into consideration for surgical
planning or diagnosis of cerebrovascular disease."
Assessment of cerebellar pulsation in dogs with and without Chiari-like
malformation and syringomyelia
using cardiac-gated cine
magnetic resonance imaging.
C.J. Driver, V. Watts, A.C. Bunck, L.M. Van
Ham, H.A. Volk. Vet.J. June 2013. Quote: "Canine Chiari-like malformation
(CM) is characterised by herniation of part of the cerebellum through the
foramen magnum. In humans with Chiari type I malformation (CM-I), abnormal
pulsation of the cerebellum during the cardiac cycle has been documented and
is pivotal to theories for the pathogenesis of syringomyelia (SM). In this
retrospective study, cardiac-gated cine balanced fast field echo (bFEE)
magnetic resonance imaging (MRI) was used to assess pulsation of the brain
in dogs and to objectively measure the degree of cerebellar pulsation with
the neck in a flexed position. Overall,
17 Cavalier King Charles
Spaniels (CKCS)
with CM, including eight with SM and nine without
SM, were compared with six small breed control dogs. Linear regions of
interest were generated for the length of cerebellar herniation from each
phase of the cardiac cycle and the degree of cerebellar pulsation was
subsequently calculated. Age, bodyweight and angle of neck flexion were also
compared.
CKCS
with CM and SM had significantly greater
pulsation of the cerebellum than control dogs
(P = 0.003) and
CKCS
with CM only (P = 0.031). There was no
significant difference in age, bodyweight and angle of neck flexion between
the three groups. Cardiac-gated cine bFEE MRI permitted the dynamic
visualisation of cerebellar pulsation in dogs. These findings support the
current theories regarding the pathogenesis of SM secondary to CM and
further highlight the similarities between canine CM and human CM-I."
Drug Interactions in Polypharmacy
. Lauren A. Trepanier. Clinician's
Brief. June 2013:23-26.
Chiari-Like Malformation in Dogs
. Dominic J. Marino, Curtis W.
Dewey.
The Chiari Malformations
; Chapter 11. Springer NY 2013.
Quote: "The Chiari I malformation in humans and Chiari-like malformation in
dogs (CLM) is a condition in which the cerebellum descends out of the
foramen magnum affecting normal cerebral spinal fluid (CSF) flow. It is
considered to be a developmental abnormality and is commonly confused with
many other conditions. Chiari-like malformation in dogs affected
approximately 85 % of
Cavalier King Charles Spaniels
evaluated, as reported in the most recent studies. The specific cause has
not been determined; however, because of an abnormal shape or reduced skull
size in the caudal occipital region, part of the cerebellum is forced
through the foramen magnum, altering CSF flow patterns. Changes in CSF
dynamics result in an abnormal accumulation of fluid within the substance of
the spinal cord called a 'syrinx.' The diagnosis of CLM in dogs and Chiari
type I in humans can only be confirmed by MRI which is essential for
determining the cause of syringomyelia. Current concepts in the diagnosis
and treatment of Chiari-like malformation in dogs will be discussed."
An update on the pathogenesis of syringomyelia secondary to Chiari-like
malformations
in dogs.
C.J. Driver, H.A. Volk, C. Rusbridge, L.M.
Van Ham. Vet.J. Aug. 2013. Quote: "Syringomyelia (SM) is a spinal cord
disease that can cause neuropathic pain in dogs. The pathogenesis of SM
secondary to Chiari-like malformation (CM) has been the focus of intense
research in recent years. The gulf in our understanding of CM/SM in dogs
relative to the analogous human condition has progressively narrowed. CM is
primarily a disease of abnormal geometric morphometry affecting the caudal
cranial fossa and the brain parenchyma contained within it. This review
describes how advanced imaging techniques have revealed a series of
morphometric abnormalities associated with CM/SM. The series is presented in
a logical order to help describe the pathogenesis of CM and the subsequent
formation of syringes, with particular reference to the concepts of
craniospinal compliance and cerebrospinal fluid pulse pressure timing. ...
Mechanical compliance determines the ability of a system to accommodate a
change in volume in the face of pressure changes. Craniospinal compliance is
the sum of the ability of both the cranial and spinal compartments to
accommodate changes in parenchymal, blood or CSF volumes, which all exist in
a state of dynamic equilibrium. Compliance is primarily concerned with the
dimensions of the skull, but is influenced by several other factors,
including CSF volume, free CSF flow, the integrity of the vasculature, space
occupying lesions, and autonomic regulation of blood flow. ... Where
craniospinal compliance is generally reduced, for example due to failed CSF
absorption into the venous sinuses, hydrocephalus and communicating SM
occur. ... We propose that CM is responsible for reduced compliance.
Further, reduced cranial compliance could result in a larger pressure
gradient between the cranial and spinal systems. ... There are two
observable outcomes of reduced compliance. Firstly, reduction of the CSF
space at the foramen magnum could lead to the retention of CSF in the head,
which would otherwise be free to move through the foramen magnum.
Ventriculomegaly is a common observation in
CKCS
with CM and in one study,
the volume of the ventricular system was positively correlated with the
severity of SM, suggesting a shared pathogenesis. However, it should be
noted that large ventricles are common in small breed dogs. Secondly,
reduced cranial compliance might affect the transition of pressure between
the blood and CSF compartments of the cranial and spinal systems. This could
explain the turbulent CSF flow patterns that were observed by Cerda-Gonzalez
et al. (2009b) at the foramen magnum. The increased cerebellar pulsation
observed in CKCS with SM by Driver et al. (2013) could also be associated
with altered pressure and compliance; however, it remains unclear whether
this is a cause or effect of this change. ... Clinically, the condition remains frustrating to treat given its variable
natural progression. In theory, surgical treatment of CM in dogs might be
appropriate to restore compliance but it is important to emphasise that
there is little information to guide the clinician regarding whether such
major surgery is appropriate or necessary when mild clinical signs are
apparent. Despite progressive neuropathic pain in the majority of cases,
most dog owners still consider their pets to have a good quality of life
with medical therapy. Further research might focus on advanced imaging
techniques to assess the clinical correlates of altered CSF hydrodynamics.
Moreover, phase contrast cMRI has been used to assess craniospinal
compliance, which could be applied in dogs. Importantly, improved
descriptions of the genes involved in formation of the hindbrain and CCF
could help to guide breeding schemes, which are problematic given the high
prevalence of the disease."
Chiari-like malformations: Is compliance the issue?
Cerda-Gonzalez,
S. Vet.J. Aug. 2013.
Retrospektive Betrachtung des Fugenschlusses der Synchondrosen der
Schadelbasis bei Hunden verschiedener Rassen unter besonderer
Berücksichtigung des
Cavalier King Charles Spaniels
Retrospective analysis of the joint conclusion of synchondroses base of
the skull in dogs of various breeds with special consideration of
Cavalier King Charles Spaniels
.) Melanie Klinger. VVB
Laufersweiler Verlag. 2013. Quote: "The cranial base has a significant role
for the development of the entire craniofacial as well as for the central
nervous system. Growth of the skull base occurs in the growth plates, the
so-called synchondroses, and ends with the ossification of the synchondroses,
which remain as synostoses. ... An extreme type of skull is shown by dogs
with a brachycephaly in which a shortening of the longitudinal axis with
compensatory broadening occurs. The
Cavalier King Charles Spaniel
(CKCS)
shows a very pronounced form of this reduced longitudinal
expansion. Furthermore, the
CKCS
shows a predisposition for
the disease complex of Chiari-like malformation (CM). The sphenooccipital
synchondrosis is the main contributor to the longitudinal growth of the
skull. The objective of the present study was to determine the closure time
in which ossification for the dogs sphenooccipital synchondrosis occurs. In
regards to the different skull types the decision was made to divide the
participants into three groups. Group 1 consisted of mesocephalic dogs which
have a skull type close to the prototype of the wolf. The second group was
composed of brachycephalic breeds. Considering the extreme brachycephaly of
the
CKCS
and the cumulation of CM in this breed, a separate
grouping of these dogs seemed necessary. The study population consisted of
67 mesocephalic and 24 brachycephalic dogs as well as of 58 animals
belonging to the
CKCS
breed. The maximum age was 18 months.
The statistical analysis results clearly showed a difference of the
ossification time at the sphenooccipital synchondrosis between the three
groups. In the
CKCS
the growth plate closure occurred about
the 5th month of life. The second group which was composed of the
brachycephalic participants of the study followed next. Finally the
synchondrosis sphenooccipitalis ossificated in representatives of
mesocephalic breeds around the 13.5th month. However the observation period
until the 18th month of life seemed to short. For some participants the
sphenooccipital synchondrosis was not closed yet. Therefore it was not
possible to make a terminal conclusion on the time of ossification with an
observation time of 18 months. However the results confirm the assumption
that the premature ossification of the sphenooccipital synchondrosis is the
cause of the reduced skull length for brachycephalic breeds. ... With regard
to the pathogenesis of the CM the present results support the exceptional
position which the
CKCS
possesses among the brachycephalic
breeds. Results of other studies which showed alterations in the
basioccipital bone of
CKCS
suffering from CM are explained.
Furthermore current concepts dealing with the development of syringomyelia
through disturbances in the venous drainage in the region of the jugular
foramen are confirmed. Continuing studies on the sutures of the calvaria are
still required to clarify the numerous parameters which contribute to the
development of CM in the
CKCS
." (See also:
Comparison of Closure Times for Cranial Base Synchondroses in
Mesaticephalic, Brachycephalic, and
Cavalier King Charles Spaniel
Dogs
.)
Pathogenesis and pain in Chiari-like malformation
Peter M. Smith. Vet.J.
Dec. 2013;198(3):545-6. Quote:
"Chiari-like malformation is now a widely recognised condition affecting
several breeds of dog. Most widely characterised in the
Cavalier
King Charles Spaniel (CKCS)
, it has since been extensively
documented, highlighting the high proportion of the breed that are affected
by the condition (
Driver
et al., 2013
). A significant proportion of dogs with Chiarilike
malformation also develop syringomyelia, an accumulation of fluid within the
spinal cord. This results in various neurological abnormalities, most
commonly allodynia (pain caused by a non-noxious stimulus) and dysaesthesia
(unpleasant abnormal sensations that can be spontaneous), causing dogs to
scratch at the neck. Severe pain develops in some cases and motor deficits
are also possible. ... Additional morphological studies, described in detail
in the review by
Driver et al. (2013)
, demonstrate the wide array of differences between
the bony and vascular structures of the skull and the cervical vertebral
column in
CKCS
and other breeds. The aim of these studies
is to establish why the cerebellum protrudes through the foramen magnum, yet
it is impossible to know whether these are responsible for the Chiari
malformation, or whether they simply reflect coincidental anatomical
variation. A similar approach to intervertebral disc disease would have
investigators measuring the size of vertebrae in Dachshunds in order to
understand what leads to disc extrusion; although intrinsically interesting
and valid research, it seems unlikely to generate significant insight into
the clinical problem. ... The pathogenesis of syrinx formation in both
humans with Chiari malformation type I and in dogs with Chiari-like
malformation has been the subject of a large amount of speculation and
experimental investigation. This is sensible clinical research; the syrinx
appears to be a significant cause of pain and understanding how it forms
might help to guide treatments to restrict its development. ...
Understanding why the syrinx forms will help to improve surgical treatments
and perhaps even lead to strategies aimed at preventing the development of
the syrinx in the first place. ... Why, then, does the syrinx not collapse
in dogs that undergo decompressive surgery? Perhaps surgery fails to address
the key problem in affected dogs. Perhaps surgery fails to address the key
problem in affected dogs. ... Although veterinary studies document
exploration of the sub-arachnoid space during surgery, it is possible that
this is insufficient to fully restore normal CSF flow at the foramen magnum.
Of course, it might also reflect the tendency for surgery to be a last
resort for dogs, selecting for those that are severely affected or have
long-standing problems. There are two therapeutic approaches to dogs with
Chiari-like malformation. Treatment with analgesics is generally successful
in palliating pain but in those that fail medication, affected dogs are
either euthanased, condemned to a life of persistent intractable pain, or
offered a surgical treatment that appears not to provide syrinx resolution
and has questionable long term benefit. It seems it is now time to divert
our attention from simple morphological observations of the
CKCS
skull to developing a better understanding of the pain suffered by affected
dogs. With greater insight into how the syrinx develops, ably documented by
Driver et al. (2013)
, we should not only aim to understand why some dogs
that undergo surgery fail to resolve their syrinx, but perhaps also try to
pre-empt the development of the syrinx in the first place."
Chiari-like malformation and syringomyelia
. Clare Rusbridge
. EJCAP,
Genetic/Hereditary Disease and Breeding. Oct. 2013;23(3):70-89. Quote: "Syringomyelia
is a condition characterised by fluid filled cavities (syrinxes or syringes)
within the central spinal cord and the resulting damage produces clinical
signs of pain and neurological deficits. Since the increase in availability
of magnetic resonance imaging (MRI), syringomyelia is an increasingly common
diagnosis in veterinary medicine. The most common cause of syringomyelia in
the dog is Chiari-like malformation (Fig 1), a condition analogous to Chiari
Type I and 0 malformation in humans. ... Chiari-like
malformation and syringomyelia is an inherited disorder with a high
morbidity in many brachycephalic toy breeds. It is characterised by
overcrowding of the craniocervical junction, obstruction of CSF flow through
the foramen magnum and development of fluid filled cavities in the central
spinal cord. Although some cases are asymptomatic, dogs with Chiari-like
malformation and syringomyelia can present with neurological signs of which
the most important is pain. Surgical and medical treatment options are
available but these have limited success and from a welfare point of view it
would be better to implement a breeding program limiting the occurrence of
this disabling disease."
The Effects of Magnetic Resonance Imaging Noise on Cochlear Function in
Dogs
Chapter 2 of "Effects of acute and chronic noise exposure on
cochlear function and hearing in dogs." Rebecca Elisabeth Venn. MSc(R)
thesis pp 21-42, University of Glasgow. 2013. Quote: "In specialised
veterinary hospitals, Magnetic Resonance Imaging (MRI) scanners are used
daily in diagnostics of dogs. MRI scanners omit high levels of acoustic
noise, which is known to be damaging to the hearing of human patients
without effective ear protection. However, the effects of the MRI noise
levels on the cochlear function and hearing of dogs is often overlooked and
in many clinics, dogs are not provided with ear protection for the duration
of their scan. The aim of this study was to assess the effects of MRI
acoustic noise on the cochlear function of dogs, by Distortion Product
Otoacoustic Emissions (DPOAE) testing dogs immediately before and after they
underwent an MRI scan. ... Thirty-six dogs were included in the MRI group
(mean age 3.9 years, median age 3 years, range 6 months to 10 years; mean
bodyweight 16.9 kg, median bodyweight 13.8 kg, range 3.5 kg to 40.8 kg) and
17 dogs were included in the control group (mean age 6.2 years, median age 7
years, range 1 year to 12 years; mean bodyweight 25.1 kg, median bodyweight
23.6 kg, range 6.7 kg to 57.8 kg). There were 16 male dogs in the MRI group
(44.4%) and 10 male dogs in the control group (58.8%). A variety of dog
breeds were represented, with those represented more than once including
three toy poodles, three Lhasa Apso dogs, four Labrador retrievers, two
cocker spaniels,
four Cavalier King Charles spaniels
, two
boxers and three cross-breeds in the MRI group, and two Labrador retrievers
and two cross-breeds in the control group.... A group of control dogs
undergoing a quiet procedure (but treated with the same range of anaesthetic
drugs) were also tested. Post-MRI, the mean DPOAE of the dogs was reduced at
all frequencies tested, significantly so at five (out of fourteen)
frequencies, reflecting a reduction in cochlear function. Furthermore, at
all frequencies tested, more than half of the ears exposed to MRI noise
demonstrated a decrease in DPOAE. ... The results from this study indicate
that exposure to noise during MRI in dogs results in a reduction in cochlear
function, which is significant at multiple sound frequencies. ... Without
repeat DPOAE testing of the dogs some weeks after their MRI, it is unknown
whether this effect is temporary and reversible, or permanent. ... Evidence
from human MRI noise exposure would suggest that this effect is temporary.
The frequency region affected is likely influenced by the frequency of the
noise spectra of the MRI. The demonstration that MRI noise results in some
degree of hearing loss, albeit only assessed in the immediate post-MRI
period in the present study, would suggest that all dogs having MRI studies
performed should have ear protection as a standard precautionary measure."
Evaluation of MR safety of a set of canine ear defenders
(MuttMuffs®) at
1 T.
Martin A. Baker. Radiography. Nov. 2013;19
(4):339-342.
Quote: "Previous studies have indicated that loud noise produced during MR
scanning is hazardous for human patients. Although loud noise can also be
harmful to canine patients in MRI, ear protection is not routinely provided.
The purpose of this study was to test the safety of a set of commercially
available canine ear defenders (MuttMuffs®) during MRI scanning at 1 T. ...
The dogs were all of the same breed (
Cavalier King Charles Spaniel
),
with half having been provided with the ear defenders and half which had
not. ... A metal fastening ring was removed and replaced with a plastic
washer prior to testing. Torque, translation, heating and artifact
production were tested. No torque, translation, or excessive heating were
detected. No artifacts were observed. Clinical use demonstrated additional
benefits of improved immobilisation of the dog, with no effect on
signal-to-noise ratio. Results from this study indicate that following
replacement of the metal ring with one made of plastic, these canine ear
defenders are suitable for use at 1 T. The author recommends the use of ear
defenders during canine MRI scans in order to reduce the risk of hearing
damage, reduce the dose needed for anaesthetic maintenance and reduce the
need for repeated MRI sequences due to movement of the dog."
Comparison of MRI and CT for the detection of cerebellar (foramen magnum)
herniation
in Cavalier King Charles spaniels.
Kromhout K., Bhatti S.,
Van Ham L., van Bree H., Gielen I. Ghent Univ. Academic Bibliography. 2013.
Quote: "Introduction: The Cavalier King Charles spaniel (CKCS) breed exhibits a
high rate of Chiari-like malformation (CM). The latter is characterised by a
disproportion of volume of the cerebellum and medulla oblongata compared to that
of the caudal fossa. These abnormalities are associated with displacement or
herniation of the most caudal areas of the cerebellum either into or through the
foramen magnum (1,2). Several articles have suggested mid-sagittal magnetic
resonance imaging (MRI) as the preferred technique for visualizing the caudal
fossa and diagnosing CM (1,3,4). This study compares MRI and computed tomography
(CT) for the detection of cerebellar herniation (CH). Materials and Methods:
Nine CKCSs were presented with a various range of neurological symptoms. MRI and
CT studies of their brains and cranial cervical spines were performed as part of
their clinical work-up with the dogs positioned in dorsal recumbency with the
head in extended position. Using sagittal T1- and T2-weighted spin echo (T1WSE
and T2WSE) MRI sequences and pre- and postcontrast CT-images, the cerebellar
herniation length (HL) (= the position of the tip of the cerebellar vermis
relative to the foramen magnum) was measured (mm) and assigned either a grade
mild (≤ 2mm) or marked (>2mm) by 2 two observers. The results were analyzed
statistically. Results: There was a perfect agreement (k=1) for both observers
for the detection of mild and marked CH for both techniques. However the
Bland-Altman plot analyses of the HL indicated that CT and MRI findings did not
agree well. The bias was significantly different from zero when comparing the HL
measurements on the CT and MRI images. The limits of agreement for all
measurements found the HL differed between techniques over a range of < 1,5 mm.
Discussion/ Conclusion: The statistical analysis suggested that both techniques
are useful for detecting CH. However because the bias was significantly
different from zero, one of the methods consistently led to the determination of
longer or shorter HL than the other method. For most comparisons, the HL was on
average longer on CT. MRI provides greater soft tissue detail with no
beam-hardening artifacts, which may improve the delineation of the cerebellum.
Because HL does affect a diagnosis of CM, so CT can be used as a primary
diagnostic tool for diagnosing CM in CKCSs when MRI is not available." See
also
Low-Field MRI and Multislice CT for the Detection of Cerebellar (Foramen
Magnum) Herniation in Cavalier King Charles Spaniels.
Prevalence of Chiari-like malformation and Syringomyelia in
Cavalier
King Charles Spaniels
in the Netherlands between 2004 and 2012
W.A. Eggelmeijer. Utrecht University; Nov. 2013. Quote: "Eight hundred and
fifteen scans were made of Cavalier King Charles spaniels. ... These 815
scans were made from 732 different CKCS. This means that 83 scans were made
from a dog that already had been scanned at least once. Of these dogs the
progression over time can be evaluated. ... The 815 scans are made of 732
dogs. Chiari-like malformation is shown in every dog, except for 1 (0,14%).
A total of 605 out of 732 dogs had a cerebellum that was misshaped with
overcrowding and indentation (82,7%). A total of 126 out of 732 dogs showed
clear herniation of the caudal part of the cerebellum (17,2%). In none of
the dogs were the tonsils maximally herniated. Syringomyelia is observed in
275 dogs (37,6%) of the 732 dogs. One hundered and sixty four dogs showed a
syrinx of more than 2 mm (22,4%) compared to one hundered and eleven dogs
with a syrinx less than 2 mm (15,2%). SM was not detected in 457 dogs.
(62,4%) Syringomyelia was seen in approximately 37,6% of the dogs with
chiari-like malformation. If the dogs had a syrinx of more than 2 mm (164
dogs), 138 dogs had a CM with a cerebellum that was misshaped with
overcrowding and indentation (84,1%) versus 26 dogs that showed clear
herniation of the caudal part of the cerebellum (15,9%). If the dogs had a
syrinx of less than 2 mm (111 dogs), 86 dogs had a CM with a cerebellum that
was misshaped with overcrowding and indentation (77,5%) versus 25 dogs that
showed clear herniation of the caudal part of the cerebellum (22,5%). ...
Conclusion Chiari-like malformation and syringomyelia are a serious problem
in the Cavalier King Charles Spaniel. There is a correlation between the
prevalence and age of the dogs. This study can not determine the original
cause of SM and any influence of CM. More research is necessary to determine
the development of SM."
The prevalence of Chiari-like malformation and Syringomyelia in several toy
breeds in the Netherlands
. P.G.Limburg. Utrecht University; Nov.
2013.
La unión cráneo-cervical: una revisión de las malformaciones de Chiari,
bandas durales y la superposición atlanto-occipital
. Sofia
Cerdá-González, Katherine Bibi. Neuro-Vet. December 2013. 117-128.
RETURN TO TOP
2014
Quantitative Analysis of Chiari-Like Malformation and Syringomyelia in the
Griffon Bruxellois Dog
. Susan P. Knowler, Angus K. McFadyen,
Courtenay Freeman, Marc Kent, Simon R. Platt, Zoha Kibar, Clare Rusbridge.
PLOS-One. Feb. 2014. Quote: "This study aimed to develop a system of
quantitative analysis of canine Chiari-like malformation and syringomyelia
on variable quality MRI. We made a series of measurements from magnetic
resonance DICOM images from Griffon Bruxellois dogs with and without
Chiari-like malformation and syringomyelia and identified several
significant variables. We found that in the Griffon Bruxellois dog,
Chiari-like malformation is characterized by an apparent shortening of the
entire cranial base and possibly by increased proximity of the atlas to the
occiput. As a compensatory change, there appears to be an increased height
of the rostral cranial cavity with lengthening of the dorsal cranial vault
and considerable reorganization of the brain parenchyma including ventral
deviation of the olfactory bulbs and rostral invagination of the cerebellum
under the occipital lobes.  ... This study supports the view that CM is
a multifactorial condition that includes the shortening of the entire
basicranium, loss of convexity of the supraoccipital bone, invagination of
the cerebellum under the occipital lobes and possibly by increased proximity
of the atlas to the occiput. As a compensatory change, there is increased
height of the rostral cranial cavity and lengthening of the dorsal cranial
vault. Overcrowding in the caudal cranial fossa and the craniocervical
junction is a defining feature. The study provides the basis of a
quantitative assessment of CM which might identify risk of syringomyelia and
suggests that CM should be redefined so that account is taken of the
overcrowding of the entire cranial fossa and craniocervical junction with
reorganization of the brain. ... we recommend that this study be repeated
and/or modified for other breeds with a high prevalence of CM and
syringomyelia such as
Cavalier King Charles spaniels
and
Chihuahuas."
A Cross-Sectional Study of Prevalence and Long-Term Outcome in Symptomatic
and Asymptomatic
Cavalier King Charles Spaniels
with
Syringomyelia
. M.S. Thofner, A.A. Madry, C.S. Stougaard, C.S. Knudsen,
H. Berg, C.S.E. Jensen, R.M.L. Handby, M. Berendt. J.Vet.Int.Med. May
2014;28:944-975. Quote: "The aim of the present study was to investigate the prevalence
of SM and long-term outcome in symptomatic and asymptomatic SM-affected
Danish Cavalier King Charles Spaniels (CKCS)
. The study was
initiated in 2007 and consisted of three phases. In phase I a
cross-sectional study was conducted to estimate the prevalence of SM in dogs
older than six years of age where clinical signs are expected to have
arisen. The study population consisted of all 240
CKCS
born
/ registered in the Danish Kennel Club in 2001. ... In phase II the
association of clinical findings and MRI findings in symptomatic and
asymptomatic siblings was investigated. The phase I prevalence study
identified several litters with symptomatic and asymptomatic siblings. Eight
litters with one or more siblings with clinical signs of SM representing 35
dogs were invited for clinical evaluation and MRI investigation. ... In 2012
a five-year follow-up investigation (phase III) of the litters investigated
in phase II was carried out. To assess the long-term outcome in symptomatic
and asymptomatic dogs with SM, the owners were contacted by phone. The
interview was based on an extensive structured questionnaire addressing the
status of the dog including symptomatic / asymptomatic, alive / dead, and
cause of dead if not alive. The estimated prevalence of clinically
symptomatic syringomyelia in Danish CKCS born in 2001 (> six years of age)
was 15.4% (CI95%: 9% - 22%). In study phase II 22 dog owners accepted to let
their dog participate in a full clinical work-up including MRI. Thirteen of
the 22 dogs (59%) were clinically classified as SM positive whereas the MRI
scans revealed a syrinx in the cervical spinal cord in 21 of 22 dogs (95%).
No statistical association between clinical signs and the presence of syrinx(es)
could be established (p = 0,41). Of the 13 dogs where the owners rejected
the MRI examination, five dogs (38%) expressed clinical signs of SM.
Ninety-two percent (32/35) of the owners participated in the 2012 follow-up.
It was found that after five years (by the age of 11) eleven of the 31 dogs
(35%) were alive while 20 (65%) had been euthanized. In four dogs (20%)
euthanasia was directly related to severe signs of SM. One dog that was
asymptomatic in the phase II investigation in 2007 did develop signs of SM
after the age of six. This study found a high prevalence (15.4%) of
symptomatic SM in the Danish
CKCS
population and revealed
that despite positive SM findings on MRI, affected dogs may be clinically
silent. Asymptomatic dogs may develop clinical signs rather late in life (in
this study after the age of six). Despite the high number of affected dogs,
euthanasia motivated by SM is relatively moderate. From a clinical point of
view our results necessitate further examination of the progression of the
disease and assessment of the threshold of outbreak of clinical symptoms."
Syringomyelia in
Hong Kong Pet Population
: 10-year Data from a Private Veterinary Clinic
(2003-2013)
. S. Guo, D. Lu. J.Vet.Int.Med. May 2014;28:944-975.. Quote: "This
retrospective study is the first novel report revealing these facts in a
private referral practice in Hong Kong, based on the cases seen from 2003 to
2013. ... A total of 189 cases were included. There were 182 dogs and 7
cats. Of these cases, the distribution is as follows: SMven (SM associated
with ventriculomegaly) (61 cases, 32.3%), SMneo (neoplasia) (23 cases,
12.2%), SMivd (intervertebral disc prolapse) (47 cases, 24.9%), SMinf
(inflammatory CNS disease) (41 cases, 21.7%), SMtra (trauma) (3 cases,
1.6%), SMmal (malformation) (6 cases, 3.2%), SMfce (fibrocartilaginous
embolism) (1 case, 0.5%) and SMund (SM with undetermined cause) (7 cases,
3.7%). The most common breed is Pomeranian (62 cases) followed by Chihuahua
(36 cases) and Yorkshire Terrier (20 cases). There are only 4 cases of
Cavalier King Charles Spaniel
, which is a breed commonly
seen with the presence of syringomyelia, indicating a geographical
distribution difference of the breeds affected. The SMven cases are likely
to be related to Chiari malformation. However, due to the variable skull
shapes of the breeds included, further study of the "normal variant"
ventricular size in Hong Kong pet population is necessary. In conclusion, MR
imaging of the brain should be included as part of the investigation if SM
is found in the spinal cord as a large proportion of the spinal SM is
associated with ventriculomegaly."
Comparison of MRI and CT for the detection of cerebellar (foramen magnum)
herniation in
Cavalier King Charles spaniels
Kromhout K., Bhatti S., Van Ham L., van Bree H., Gielen I. Ghent Univ.
Academic Bibliography. 2013. Quote: "Introduction: The
Cavalier King
Charles spaniel (CKCS)
breed exhibits a high rate of Chiari-like
malformation (CM). The latter is characterised by a disproportion of volume
of the cerebellum and medulla oblongata compared to that of the caudal fossa.
These abnormalities are associated with displacement or herniation of the
most caudal areas of the cerebellum either into or through the foramen
magnum (1,2). Several articles have suggested mid-sagittal magnetic
resonance imaging (MRI) as the preferred technique for visualizing the
caudal fossa and diagnosing CM (1,3,4). This study compares MRI and computed
tomography (CT) for the detection of cerebellar herniation (CH). Materials
and Methods:
Nine CKCSs
were presented with a various range
of neurological symptoms. MRI and CT studies of their brains and cranial
cervical spines were performed as part of their clinical work-up with the
dogs positioned in dorsal recumbency with the head in extended position.
Using sagittal T1- and T2-weighted spin echo (T1WSE and T2WSE) MRI sequences
and pre- and postcontrast CT-images, the cerebellar herniation length (HL)
(= the position of the tip of the cerebellar vermis relative to the foramen
magnum) was measured (mm) and assigned either a grade mild (≤ 2mm) or marked
(>2mm) by 2 two observers. The results were analyzed statistically. Results:
There was a perfect agreement (k=1) for both observers for the detection of
mild and marked CH for both techniques. However the Bland-Altman plot
analyses of the HL indicated that CT and MRI findings did not agree well.
The bias was significantly different from zero when comparing the HL
measurements on the CT and MRI images. The limits of agreement for all
measurements found the HL differed between techniques over a range of < 1,5
mm. Discussion/ Conclusion: The statistical analysis suggested that both
techniques are useful for detecting CH. However because the bias was
significantly different from zero, one of the methods consistently led to
the determination of longer or shorter HL than the other method. For most
comparisons, the HL was on average longer on CT. MRI provides greater soft
tissue detail with no beam-hardening artifacts, which may improve the
delineation of the cerebellum. Because HL does affect a diagnosis of CM, so
CT can be used as a primary diagnostic tool for diagnosing CM in
CKCSs
when MRI is not available."
See also
Low-Field MRI and Multislice CT for the Detection of Cerebellar (Foramen Magnum)
Herniation in Cavalier King Charles Spaniels.
Assoziation zephalometrischer Parameter mit dem Auftreten der Syringomyelie
beim
Cavalier King Charles Spaniel
mit Chiari-ahnlicher
Malformation
[Association of anatomical parameters with the occurrence of
syringomyelia in the
Cavalier King Charles Spaniel
with
Chiari malformation]
. Annabell Johanna Grübmeyer. Giessener
Elektronische Bibliothek. Jan. 2014. Quote: "Until now the Chiari-like
malformation was only diagnosed in brachycephalic dog breeds. Based on the
decreased length-breadth ratio of its skull the
Cavalier King
Charles Spaniel
can be classified as a highly brachycephalic dog.
Therefore it could be assumed that the grade of brachycephaly is a
pathophysiological factor for the development of syringomyelia and a
retarded length growth of the skull might be the cause for the changes found
in the Chiari-like malformation. The question is, if a
shortening of the cranial base gives rise to the pathological changes in
Chiari-like malformation. Based on this question we examined the anatomical
parameters of
107 Cavalier King Charles Spaniels
in
relationship to the occurrence of syringomyelia. The study should give
information about the pathogenesis of the Chiari-like malformation and the
development of syringomyelia and if there is a difference in the cranial
base length in
Cavalier King Charles Spaniels
with or
without syringomyelia. The 107
Cavalier King Charles Spaniels
examined in this study were mostly presented for breeding examinations, but
some were also presented because of clinical signs. The age of the examined
dogs ranged from 6 month to 9 years. We performed computed tomography of the
skull and magnetic resonance imaging of the skull and spine of all patients.
The examination of the spine in patients introduced for breeding
examinations, were performed until the 5th cervical vertebra. In patients
with neurological signs the examination included also the caudal cervical,
thoracic and lumbar spine. Changes consistent with the Chiari-like
malformation were found in all 107
Cavalier King Charles Spaniels
63 of the 107 dogs showed a syringomyelia at the point of examination. The
results of the study showed that the incidence of syringomyelia is
correlated to the variables age (p less than 0,007), SBI [skull base index]
(p less than 0,0192), PI [presphenoid index] (p less than 0,0447) and BI
[basisphenoid index]  (p less than 0,0206). Furthermore it is shown
that
Cavalier King Charles Spaniels
with a decrease in SBI
have an increased risk to develop syringomyelia (odds ratio 1,26). In
addition also the presphenoid and the basioccipital bone showed a reduced
length, with an increase in breadth in dogs with syringomyelia. This study
showed, that a reduced length of the cranial base represents a risk factor
for the occurrence of syringomyelia. These results support the assumption of
other authors that the cause of the Chiari-like malformation and
syringomyelia is up to a growth disturbance of the cranial base."
Zur Okzipitalen Dysplasie des Foramen magnum und Morphometrie des Atlas beim
Hund. Eine computertomographische Studie
. [The occipital dysplasia of
the Foramen magnum and the morphometry of the atlas in dogs. A computer
tomographic study.]
Iris Sporl. Ludwig-Maximilians-University Munich.
Quote: "Aim of this study is a computer tomographic representation of the
differences in the morphometry of the foramen magnum and the atlas in dogs.
Dogs included in the study were divided into three groups: neurologically
healthy toy breed dogs (group 1), dogs with atlanto-axial instability (group
2) and large breed dogs. Occipital dysplasia is defined as a varying dorsal
notch of the foramen magnum in toy breed dogs. Degree of dysplasia, the
dorsal notch index, the occipital index and the foramen magnum index were
being calculated and all four of them showed significant differences in
those three groups. Large breed dogs showed a normal transverse ovoid shape
without a dorsal notch. Neurologically healthy toy breed dogs had a
relatively wide foramen magnum with a dorsal notch and a big variety of
shapes. In comparison to former studies based on toy breed sculls the
results were similar, whereas radiological examinations showed lower values.
Both dogs with an AaI and neurologically healthy toy breed dogs had a wider
foramen magnum, which is more distinct in the latter. In the transversal
plane of the atlas the vertebral chanal has been measured and classified in
vertically oval-round and cross-oval. In the sagittal plane the relation of
the atlas´ inside diameter and the dorsal arch´s length has been calculated
and thus the ratio has been determined. The side ratio could be greater than
1 or less than or equal to 1. Large breed dogs with a vertically oval-round
vertebral chanal had a side ratio equal to 1 which is physiological. The
side ratio in healthy toy breed dogs and dogs with AaI was greater than 1,
which means, that this too is a morphological variation in toy breed dogs.
The vertebral chanal in those two groups was cross ovoid."
Quantitative Trait Loci (QTL) Study Identifies Novel Genomic Regions
Associated to Chiari-Like Malformation in Griffon Bruxellois Dogs
Philippe Lemay, Susan P. Knowler, Samir Bouasker, Yohann Nedelec, Simon
Platt, Courtenay Freeman, Georgina Child, Luis B. Barreiro, Guy A. Rouleau,
Clare Rusbridge, Zoha Kibar. PLOS One. April 2014. Quote: "Chiari-like
malformation (CM) is a developmental abnormality of the craniocervical
junction that is common in the Griffon Bruxellois (GB) breed with an
estimated prevalence of 65%. This disease is characterized by overcrowding
of the neural parenchyma at the craniocervical junction and disturbance of
cerebrospinal fluid (CSF) flow. The most common clinical sign is pain either
as a direct consequence of CM or neuropathic pain as a consequence of
secondary syringomyelia. The etiology of CM remains unknown but genetic
factors play an important role. To investigate the genetic complexity of the
disease, a quantitative trait locus (QTL) approach was adopted. A total of
14 quantitative skull and atlas measurements were taken and were tested for
association to CM. Six traits were found to be associated to CM and were
subjected to a whole-genome association study using the Illumina canine high
density bead chip in 74 GB dogs (50 affected and 24 controls). Linear and
mixed regression analyses identified associated single nucleotide
polymorphisms (SNPs) on 5 Canis Familiaris Autosomes (CFAs): CFA2, CFA9,
CFA12, CFA14 and CFA24. A reconstructed haplotype of 0.53 Mb on CFA2
strongly associated to the height of the cranial fossa (diameter F) and an
haplotype of 2.5 Mb on CFA14 associated to both the height of the rostral
part of the caudal cranial fossa (AE) and the height of the brain (FG) were
significantly associated to CM after 10 000 permutations strengthening their
candidacy for this disease (P = 0.0421, P = 0.0094 respectively). The CFA2
QTL harbours the Sall-1 gene which is an excellent candidate since its
orthologue in humans is mutated in Townes-Brocks syndrome which has
previously been associated to Chiari malformation I. Our study demonstrates
the implication of multiple traits in the etiology of CM and has
successfully identified two new QTL associated to CM and a potential
candidate gene."
Intermittent Pain & Scratching in a
Cavalier King Charles
Spaniel
. Megan Stout Steele, Jonathan Levine.
Clinicians Brief. May 2014. Quote: "Lucy, a 7-year-old spayed
Cavalier King Charles spaniel
, was presented for
chronic intermittent cervical pain and scratching of the head and
neck. History: ... Lucy had a 2- to 3-year history of intermittent
episodes of vocalization and reluctance to be touched around the
head and neck. In addition, the dog frequently attempted to scratch
her head, neck, muzzle, and ears, although rarely did the paws come
into contact with the skin surface. During the past year, the dog
had progressive difficulty using her pelvic limbs on slippery
surfaces. The owners also suspected some hearing loss. Examination:
... Bilateral mild ceruminous otic debris was noted. The dog's
mentation appeared normal and no cranial nerve deficits were noted;
however, response to auditory stimuli was absent bilaterally. On
gait analysis, mild generalized proprioceptive ataxia, cerebellar
ataxia, and tetraparesis were noted. Myotatic reflexes were
increased in the pelvic limbs, and thoracic limb flexor withdrawal
reflexes were diminished bilaterally. Cervical pain and phantom
scratching were elicited during vertebral column palpation. Lesions
were localized to the C6-T2 spinal cord segments, cerebellum, and
auditory apparatus. Diagnostics: CBC, serum chemistry panel, and
urinalysis results were within reference ranges. Three-view thoracic
radiographs showed no abnormalities. MRI of the brain and cranial
cervical vertebral column showed cerebellar compression and coning
secondary to the malformed caudal occipital bone, with lack of
normal cerebrospinal fluid (CSF) surrounding the caudal cerebellum.
A T2 hyperintense-T1 hypointense lesion within the spinal cord
parenchyma from the level of C1 caudally was noted. The tympanic
bullae contained T2-hyperintense and T1-isointense material. No
contrast enhancement was identified. Diagnosis: Chiari-like
malformation (CLM) and syringohydromyelia (SHM); bilateral primary
secretory otitis media (PSOM). Treatment: Lucy was admitted for
additional diagnostic testing and treatment and underwent
myringotomy and bilateral deep ear flushing. Large, clear mucus
plugs were removed from both middle ears; culture of the plugs was
negative for bacteria. These findings and the MRI results were most
consistent with PSOM. The patient recovered well from anesthesia and
the next day was reanesthetized for foramen magnum decompression and
C1 dorsal laminectomy with durotomy. Surgical recovery was
uncomplicated. After 3 days, the patient was discharged with
pregabalin at 2 mg/kg PO q12h for neuropathic pain associated with
SHM, omeprazole at 1 mg/kg PO q24h to decrease CSF production, and
tramadol at 4 mg/kg PO q8h for 5 days to address temporary soft
tissue pain. In addition, N-acetylcysteine at 600 mg PO q24h was
prescribed as a mucolytic to lower the risk for PSOM recurrence.
Outcome: At the 1-month reevaluation, the dog's hearing seemed to
have improved, but her gait abnormalities and phantom scratching
persisted."
Comparison of the endocranial- and brain volumes in brachycephalic dogs,
mesaticephalic dogs and
Cavalier King Charles spaniels
in
relation to their body weight
. Martin J Schmidt, Kerstin H Amort,
Klaus Failing, Melanie Klingler, Martin Kramer and Nele Ondreka. Acta
Veterinaria Scandinavica. May 2014;56:30. Quote: "Background: A number of
studies have attempted to quantify the relative volumes of the endocranial
volume and brain parenchyma in association with the pathogenesis of the
Chiari-like malformation (CLM) in the
Cavalier King Charles spaniel
(CKCS)
. In our study we examine the influence of allometric scaling
of the brain and cranial cavity volume on morphological parameters in
different dog breeds. MRI scans of 110 dogs (35 mesaticephalic dogs, 35
brachycephalic dogs,
20 CKCSs with SM
, and
20 CKCSs
without SM
) have been used to create 3-dimensional volumetric
models of skull and brain parts. Volumes were related to body weight
calculating the adjusted means for different breeds. Results: There was a
strong global dependency of all volumes to body weight (P < 0.0001). The
adjusted means of the absolute and relative volumes of brain parenchyma and
cranial compartments are not significantly larger in
CKCSs
in comparison to brachycephalic and mesaticephalic dogs. A difference in
absolute or relative volumes between
CKCSs
with and without
SM after relating these values to body weight could not be identified. The
relative volume of the hindbrain parenchyma (caudal fossa parenchyma
percentage) was larger in brachycephalic dogs than in
CKCSs
without causing herniation or SM. Conclusion: An influence of body weight
exist in dogs, which can be sufficiently large to render conclusions on the
difference in volumes of the brain and skull unsafe unless some account of
the body weight is taken in the analysis. The results of this study
challenge the role of overcrowding for the development of SM in dogs."
Relationship of dorsal atlantoaxial junction compressive lesions (dural
bands) to clinical signs and syringomyelia in
cavalier king charles
spaniels
S. Cerda-Gonzalez, N.J. Olby, E.H. Griffith.
J.Vet.Int.Med. July 2014;28(4):1357. Quote: "Dorsal compressive lesions at the
atlantoaxial junction (i.e. dural bands) are a well-recognized
craniocervical junction anomaly, frequently seen alongside other
craniocervical junction anomalies such as Chiari-like malformations. Despite
their regular identification on imaging, their clinical significance remains
unclear. To address this, the authors investigated their influence on
clinical status and on syringomyelia in a commonly affected breed.
Thirty-six Cavalier King Charles spaniels (CKCS)
were assessed for
neuropathic pain and neurologic dysfunction, and were assigned a neurologic
grade. Magnetic resonance imaging of the craniocervical junction was
performed, with the head and neck straight and flexed. Imaging studies were
then assessed for a dural band, a Chiari-like malformation (CM), and
syringomyelia. Dural band and syringomyelia severity was determined using
both a compression index (objective) and grading (subjective), respectively.
Of the
36 CKCS
imaged, 20 demonstrated neuropathic pain.
Dural bands were present in 31/36 (83.8%) dogs; 34 had a CM. Syringomyelia
was found in 23 (56.8%) dogs, 21 of which also had a dural band. Dural bands
were associated with both the presence and severity of clinical signs, and
the presence of syringomyelia. Higher compression indices were associated
with more severe syringomyelia."
Magnetic resonance imaging signs of presumed
elevated intracranial pressure in dogs
. S. Bittermann, J. Lang, D.
Henke, J. Howard, D. Gorgas. Vet.J. July 2014;201(1):101-108. Quote: "The
aim of this study was to describe magnetic resonance imaging (MRI) findings
associated with presumed elevated intracranial pressure (ICP) in dogs and to
evaluate whether MRI could be used to discriminate between dogs with and
without elevated ICP. Of 91 dogs that underwent cranial MRI examination, 18
(19.8%) were diagnosed with elevated ICP based on neurological examination,
fundoscopy and transcranial Doppler ultrasonography. The MRI findings that
showed the strongest association with elevated ICP were mass effect (odds
ratio [OR], 78.5), caudal transtentorial herniation (OR, 72.0), subfalcine
herniation (OR, 45.6), perilesional oedema (OR, 34.0), displacement of the
lamina quadrigemina (OR, 27.7) and effacement of the cerebral sulci (OR,
27.1). The presence of any two or more of the following MRI findings
identified elevated ICP with a sensitivity of 72% and a specificity of 96%:
compression of the suprapineal recess, compression of the third ventricle,
compression of the fourth ventricle, effacement of the cerebral sulci and
caudal transposition of the lamina quadrigemina. In conclusion, there is an
association between MRI findings and elevated ICP in dogs; therefore, MRI
might be useful to discriminate between dogs with and without elevated ICP."
Syringomyelia: determining risk and protective factors in the conformation
of the
Cavalier King Charles Spaniel
dog
Thomas
J. Mitchell, Susan P. Knowler, Henny van den Berg, Jane Sykes, Clare
Rusbridge. Canine Genetics & Epidemiology. July 2014. Quote: "Syringomyelia
(SM) is a painful condition, more common in toy breeds, including the
Cavalier King Charles Spaniel (CKCS)
, than other breeds. In
these toy breeds, SM is usually secondary to a specific malformation of the
skull (called Chiari-like Malformation, CM for short). There has been debate
as to whether head shape is related to CM/SM, especially as some humans have
similar characteristic facial and skull shapes, and what this may be.
Identifying a head shape in dogs that is associated with these diseases
would allow for selection away from these conditions and could be used to
further breeding guidelines. 133 dogs were measured in several countries
using a standardised 'bony landmark' measuring system and photo analysis by
trained researchers. This paper describes two significant risk factors
associated with CM/SM in the skull shape of the
CKCS
extent of brachycephaly (the broadness of the cranium (top of skull)
relative to its length) and distribution of doming of the cranium. The study
showed that having a decreased cephalic index (less brachycephaly) was
significantly protective. Further to this, more cranium at the back of the
head (caudally) relative to the amount at the front of the head (rostrally)
was significantly protective against disease development. This was shown at
three and five years of age, and also when comparing a sample of "SM clear"
individuals over five years to those affected under three years. This study
suggests that brachycephaly, with resulting rostrocaudal doming, is
associated with CM/SM. These results could provide a way for selection
against the risk head shape in the
CKCS
, and thus enable a
reduction in CM/SM incidence. Studying other breeds in which CM free
individuals are more frequent may validate this risk phenotype for CM too."
Micronized/ultramicronized palmitoylethanolamide displays superior oral
efficacy compared to nonmicronized palmitoylethanolamide in a rat model of
inflammatory pain
. Daniela Impellizzeri, Giuseppe Bruschetta,
Marika Cordaro, Rosalia Crupi, Rosalba Siracusa, Emanuela Esposito,
Salvatore Cuzzocrea. Neuroinflammation. August 2014; doi:
10.1186/s12974-014-0136-0. Quote: Background: The fatty acid amide
palmitoylethanolamide (PEA) has been studied extensively for its
anti-inflammatory and neuroprotective actions. The lipidic nature and large
particle size of PEA in the native state may limit its solubility and
bioavailability when given orally, however. Micronized formulations of a
drug enhance its rate of dissolution and reduce variability of absorption
when orally administered. The present study was thus designed to evaluate
the oral anti-inflammatory efficacy of micronized/ultramicronized versus
nonmicronized PEA formulations. Methods: Micronized/ultramicronized PEA was
produced by the air-jet milling technique, and the various PEA preparations
were subjected to physicochemical characterization to determine particle
size distribution and purity. Each PEA formulation was then assessed for its
anti-inflammatory effects when given orally in the carrageenan-induced rat
paw model of inflammation, a well-established paradigm of edema formation
and thermal hyperalgesia. Results: Intraplantar injection of carrageenan
into the right hind paw led to a marked accumulation of infiltrating
inflammatory cells and increased myeloperoxidase activity. Both parameters
were significantly decreased by orally given micronized PEA (PEA-m; 10
mg/kg) or ultramicronized PEA (PEA-um; 10 mg/kg), but not nonmicronized
PeaPure (10 mg/kg). Further, carrageenan-induced paw edema and thermal
hyperalgesia were markedly and significantly reduced by oral treatment with
micronized PEA-m and ultramicronized PEA-um at each time point compared to
nonmicronized PeaPure. However, when given by the intraperitoneal route, all
PEA formulations proved effective. Conclusions: These findings illustrate
the superior anti-inflammatory action exerted by orally administered,
micronized PEA-m and ultramicronized PEA-um, versus that of nonmicronized
PeaPure, in the rat paw carrageenan model of inflammatory pain.
Chiari-Like Malformation and Syringomyelia in American Brussels Griffon Dogs
A.C. Freeman, S.R. Platt, M. Kent, E. Huguet, C. Rusbridge, S. Holmes.
J.Vet.Int.Med.; Sept. 2014;28(5):1551-1559. Quote: "Background: Although Chiari-like
malformation (CM) and syringomyelia (SM) have been described in many small
breed dogs, the prevalence and clinical manifestations of this complex have
not been documented in a large cohort of American Brussels Griffon (ABG)
dogs. Objectives: To characterize the clinical and magnetic resonance
imaging (MRI) features of CM and SM in the ABG breed. Animals: Eighty-four
American Kennel Club registered ABG dogs were recruited. Methods:
Prospective study. Complete histories and neurologic examinations were
obtained before MRI. Images were blindly reviewed and calculations were made
by using OsiriX. All analyses were performed by Student's t-test, Spearman's
correlation, ANOVA, and chi-square test where appropriate. Results:
Chiari-like malformation and SM were present in 65% and 52% of dogs,
respectively. Twenty-eight percent of dogs had neurologic deficits and 20%
had neck pain. Mean central canal (CC) transverse height was 2.5 mm with a
mean length of 3.6 cervical vertebrae. Neurologic deficits were
significantly associated with a larger syrinx (P = .04, P = .08) and syrinx
size increased with age (P = .027). SM was associated with a smaller
craniocervical junction (CCJ) height (P = .04) and larger ventricles (P =
.0001; P < .001). Conclusions and Clinical Importance: Syringomyelia and CM
are prevalent in American Brussels Griffon dogs. Syrinx size is associated
with neurologic deficits, CM, larger ventricles, a smaller craniocervical
junction height, neurologic deficits, and cerebellar herniation. Fifty-two
percent of dogs with a SM were clinically normal."
Syringomyelia in
cavalier King Charles spaniels
and the
incidence in South Africa
. A. J. Carter. WSAVA Congress 2014. Sept.
2014. Proceedings Book pp. 32-35. Quote: "Syringomyelia is highly prevalent
within the South African
Cavalier King Charles Spaniels
. I
have been involved in a screening program with the
CKCS
breeders and to date we have screened about 85 dogs and this process is
ongoing at the moment. The prevalence of syringomyelia in
CKCS
in South Africa is 41%. The grading system provides information for the
breeders with regards to selecting dogs for breeding and reducing the
incidence of syringomyelia. The major short fall of the grading system (2006
grading system) is that it relies on the breeder to declare any clinical
signs that are evident in their dogs that are noticed in the home
environment as the clinical signs are often subtle and not evident in the
consulting room. This makes differentiation between the grading of D and E
from F dependant on the breeder which is critical to the breeding program
and if the breeder wants to conceal the clinical symptoms the eradication of
the problem will be hindered. The 2012 grading scheme is more simplified and
does away with clinical signs as part of the grading criteria except to say
that if clinical signs are evident then dogs should not be used for
breeding. The
CKCS
also suffers from hereditary mitral
valve disease and this needs to be screened at the same time as
syringomyelia screaming. If the breeders are to reduce the incidence of the
condition then strict screening and breeding programs will need to be
implemented."
Association between the findings on magnetic resonance imaging screening for
syringomyelia in asymptomatic
cavalier king charles spaniels
and observation of clinical signs consistent with syringomyelia in later
life
. E.J. Ives, L. Doyle, M. Holmes, T.L. Williams, A.E.
Vanhaesebrouck. Vet.J. January 2015;203(1):129-130. Quote: "The likelihood of an
asymptomatic dog developing clinical syringomyelia in later life is unknown.
Association of magnetic resonance imaging findings in asymptomatic dogs and
clinical signs in later life was investigated. A questionnaire based study
was used to investigate the association between the findings on magnetic
resonance imaging (MRI) screening for syringomyelia (SM) in 79 asymptomatic
Cavalier King Charles spaniels (CKCS)
and the subsequent
development of clinical signs consistent with SM in later life. Owners
reported clinical signs consistent with SM in 13/79 (16%) dogs at the time
of the questionnaire. Asymptomatic dogs with a syrinx appear more likely to
display clinical signs than those without. A significantly greater
proportion of
CKCS
with a syrinx visible on MRI screening
showed clinical signs in later life (9/25, 36%) than dogs without a visible
syrinx (4/54, 7%; odds ratio 6.9). Whether the findings of MRI screening can
be used to indicate the likelihood of an asymptomatic
CKCS
developing
clinical signs consistent with SM in later life warrants further prospective
study in a larger cohort of dogs.
RETURN TO TOP
2015
Prevalence and Heritability of Symptomatic Syringomyelia in
Cavalier
King Charles Spaniels
and Long-term Outcome in Symptomatic and
Asymptomatic Littermates
. M.S. Thøfner, C.L. Stougaard, U. Westrup,
A.A. Madry, C.S. Knudsen, H. Berg, C.S.E. Jensen, R.M.L. Handby, H. Gredal,
M. Fredholm, M. Berendt. J.Vet.Internal Medicine. January 2015;29(1):243-250. Quote:
"Background: Syringomyelia (SM) is common in the
Cavalier King
Charles Spaniel (CKCS)
. Dogs with syrinxes express clinical signs
or might be clinically silent. Objectives: To investigate the prevalence and
heritability of symptomatic SM, the association between clinical signs and
magnetic resonance imaging (MRI) findings, and long-term outcome. Animals:
All
CKCS
registered in the Danish Kennel Club in 2001 (n =
240). Methods: A cross-sectional questionnaire-based prevalence study
validated by telephone interviews and clinically investigated clinical signs
of SM. Dogs were 6 years at the time of investigation. A prospective
observational litter study including clinical investi-gations, MRI and
5-year follow-up of symptomatic and asymptomatic siblings. Heritability was
estimated based on the scale of liability in the study population and litter
cohort. Results: The cross-sectional study estimated a prevalence of
symptomatic SM at 15.4% in the population. Thirteen symptomatic and 9
asymptomatic siblings participated in the litter study. Spinal cord syrinxes
were confirmed in 21 of 22 littermates (95%). Syrinx diameter and mean
syrinx : spinal cord ratio were significantly correlated with clinical signs
(P < .01). Estimated heritability of symptomatic SM was 0.81. Symptomatic SM
motivated euthanasia in 20%. Dogs with syrinxes, which expressed no clinical
signs at the age of 6, remained asymptomatic in 14/15 cases (93%).
Conclusions and Clinical Importance: The prevalence of symptomatic SM is
high and genetics have a high impact on clinical disease expression. Further
investigations of factors influencing the outbreak threshold of clinical
signs of SM are desirable."
See ECVN/ESVN 26th Symposium abstract above.
Prevalence of Chiari-like Malformations in Clinically Unaffected Dogs
T.R. Harcourt-Brown, J. Campbell, C. Warren-Smith, N.D. Jeffery, N.P.
Granger. J.Vet. Internal Medicine. January 2015;29(1):231-237. Quote: "Background: The
importance of Chiari-like malformation (CM) in the generation of clinical
signs or the formation of syringomyelia in dogs is incompletely understood,
partly because the prevalence of various CM definitions in unaffected dogs
is unknown. Hypothesis/ Objectives: The aims were: to estimate the
prevalence of CM in dogs asymptomatic for CM or syringomyelia, according to
3 currently used definitions [Definitions: 1. Indentation: indentation of
the caudal aspect of the cerebellum --- defined as a concave, rather than
flattened or convex, caudal border of the cerebellum. 2. Impaction:
impaction of the cerebellar vermis into the foramen magnum --- defined as
deformation of the shape of caudo-ventral vermis into a point such that the
angle between lines drawn along the caudal and ventral borders of the
cerebellum meet at an acute, rather than an obtuse, angle. This definition
was considered analogous to descent into the foramen magnum that has been
used previously. 3. Herniation: herniation of the cerebellar vermis through
the foramen magnum --- defined as extension of the cerebellar vermis caudal
to a line drawn between the ventral aspect of the supraoccipital bone
(opisthion) and the caudal border of the basioccipital bone (basion) -- our
primary aim was to establish the prevalence of CM in non-CKCS dogs]; and, to
investigate the effect of brachycephaly and head position during magnetic
resonance (MR) imaging on estimates of the prevalence of CM. Animals: 199
client-owned dogs without apparent signs of CM or syringomyelia [14
cavalier King Charles spaniels (CKCS
); 12 Staffordshire bull
terriers; 12 Jack Russell terriers; 11 Cocker spaniels; 22 Labrador
retrievers; 14 Springer spaniels; 11 golden retrievers]. Methods: Archived
MR images were analyzed for evidence of cerebellar indentation and impaction
into or herniation through the foramen magnum. Logistic regression analysis
was used to investigate the relationship of CM diagnosis with head position
and the cranial index (a measure of brachycephaly). Results: In 185 non-CKCS
dogs, indentation was identified in 44% (95% CI, 47-51%) and impaction in
22% (95% CI, 16-28%). No non-CKCS dogs showed herniation; [100% of
CKCSs
had indentation, 86% showed impaction, and 29% of
CKCS
s showed herniation (11-55%)]. Regression analysis showed a
significant increase in the odds of indentation and impaction in an extended
head position and as the cranial index increased (became more
brachycephalic). Conclusions and Clinical Importance: We conclude there is a
high prevalence of cerebellar indentation and impaction in the normal canine
population, suggesting they are unreliable as defining factors for CM. Our
data supported the hypothesis that some measures of brachycephaly are
associated with indentation or impaction, but the overlap in these
measurements among breeds showed that construction of control groups based
on subjective assessment of skull type could be inappropriate. Instead, it
may be better for future studies investigating the relationship between
abnormalities of the caudal cranial fossa and clinical signs or
syringomyelia to define control groups based on the absence of specific
anatomical features considered important (eg, cerebellar herniation,
obstruction to CSF flow at the foramen magnum)."
Low-Field MRI and Multislice CT for the Detection of Cerebellar (Foramen
Magnum) Herniation in
Cavalier King Charles Spaniels
K. Kromhout, H. van Bree, B.J.G. Broeckx, S. Bhatti, L. Van Ham, I. Polis,
I. Gielen. J. Vet. Int. Med. January 2015;29(1):238-242. Quote: "Background:
Cavalier
King Charles Spaniels (CKCS)
have a high prevalence of Chiari-like
malformation (CM). Herniation of the cerebellum into the foramen magnum is a
key diagnostic feature for CM. Midsagittal MR images are the preferred
technique for visualizing cerebellar herniation (CH). Objective: To
investigate whether CT can be used to diagnose CH. Animals: Fifteen
client-owned
CKCS dogs
referred for investigation of the
brain and cranial cervical spine on MRI and CT. Methods: Two reviewers
retrospectively analyzed midsagittal T1WSE and T2WSE MR images and
midsagittal pre- and postcontrast 2D multiplanar reformatted CT images from
each dog for the presence of CH. And, if present, the length (mm, CHL) of
the herniation was measured. The results were analyzed statistically.
Results: There was no significant difference between the different observers
and techniques for the detection of CH and measurement of CHL. Overall, the
CHL was longer on the CT images. Conclusion and Clinical Importance: Both
techniques are useful for detecting CH and measuring CHL. Because CHL does
not have a known direct impact on the clinical presentation of CM, CT can be
used as a diagnostic tool in a routine clinical practice for CM in CKCS when
MRI is not available. We emphasize that MRI is the standard screening
technique in CKCS for breeding purposes to detect the presence of CM and SM
and, at the current time, CT cannot replace MRI."
See also,
Comparison of MRI and CT for the detection of cerebellar (foramen magnum)
herniation in Cavalier King Charles spaniels.
Dilemma in the diversity of foramen magnum dimensions
David
Kilroy, Arun Kumar. BEMS Reports. Jan. 2015;1(1):3-6. Quote: "Foramen
magnum, which is an opening for the passage of spinal cord is highly
variable in its dimensions, the reasons for which are not known. In this
report we examined a few skulls from different species and performed
selective morphometric analysis (Condyle ratio, Nuchal ratio and radius) to
derive possible explanations for variations in size of foramen magnum. ...
Non-invasive determination of foramen magnum diameter may also have utility
in prediction of individuals prone for herniation of the cerebellum,
especially in species, which are predisposed to this condition. For instance
Cavalier King Charles Spaniels
have high predisposition
toherniation of the cerebellum into the foramen magnum. Hence it will be
interesting to evaluate if radius analysis of foramen magnum diameter and
its symmetry would be of help to identify individual dogs prone for
herniation of the cerebellum. ... We propose possible influence of
variations in dimension of foramen magnum on a few physio-anatomical traits,
which necessitates further research."
Foramen magnum decompression surgery in 23 Chiari-like malformation patients
2007-2010: Outcomes and owner survey results
Ortinau N, Vitale S,
Akin EY, Beasley M, Shores A. Canadian Vet. J. March 2015;56(3):288-291.
Quote: "Chiari-like malformation (CLM) with syringomyelia (SM) in dogs is
particularly prominent in the
Cavalier King Charles spanie
breed, but has also been reported in several other small breed dogs. ...
Dogs were considered surgical candidates if they met all the criteria shown
[below] and received oral medications [gabapentin, 5 mg/kg body weight (BW),
q8h, and omeprazole, 1 mg/kg BW, q24h] for 2 wk prior to surgery: 1. MRI
evidence of Chiari-like malformation and cervical syringomyelia; 2. Syrinx
in the cervical spinal cord measuring >3mm diameter on transverse T2 MRI; 3.
Clinical signs of phantom scratching, cervical pain or hypersensitivity, or
thoracic limb paresis without MRI/CSF evidence of other changes that could
produce the same clinical signs. ... These criteria were based on clinical
impressions from examination and treatment of CLM-SM patients over several
years and remain unproven. Severely affected patients with syrinxes <3mm in
diameter that respond poorly to medical management might also benefit from
surgery. ... Over a
period of 3 years, 23 canine patients [including
18 CKCSs
] were treated surgically for CLM-SM.
Surgery consisted of foramen magnum decompression, durotomy, duraplasty, and
free autogenous adipose tissue grafting (fat graft). All patients were
re-evaluated clinically at least 1 month after surgery and some up to 3
years after surgery. Improvement was noted on all clinical evaluations. A
questionnaire was mailed to all 23 owners after a period of at least 1 year
after surgery. Seventeen surveys were returned. No patient has required
additional surgery to date, 94% (16/17) had some improvement in quality of
life after surgery, and none were judged to deteriorate to less than the
pre-surgical status. The authors conclude that this surgical procedure,
combined with medical therapy, resulted in favorable long-term outcomes."
"Under the weather?" Comparing barometric pressure
with clinical signs of Chiari malformation and syringomyelia in
Cavalier King Charles Spaniels
. William Warman, Edward Ives,
Clare Rusbridge. BSAVA Conf. April 2015. Abstract Pg. 444. Quote:
"Anecdotally, changes in barometric pressure can lead to changes in degrees
of discomfort for dogs affected by Chiari Malformation and Syringomyelia
(CM/SM). This prospective, blinded study aimed to determine whether
correlation exists between changes in local barometric pressure and the
ownerperceived comfort of
Cavalier King Charles Spaniels (CKCS)
with CM/SM. Such data could allow alteration of medications to reduce
episode severity during barometric pressure changes, or the development of a
weather warning system to predict exacerbation of clinical signs before this
occurs. Owners of
CKCS
with CM/SM were requested to
complete questionnaires providing background information and daily comfort
grading scores for their dogs. Daily comfort grading score and change in
comfort score between days were compared to local mean daily barometric
pressure and pressure changes both during and between days from
Meteorological Office data over a 3 month period. Questionnaires for 22 dogs
were analysed, producing 1826 data points. Reported changes from baseline
medication were adjusted for in the statistical analysis. No correlation
between mean daily barometric pressure and daily comfort grading score was
found (spearman's rho = 0.03, P = 0.23). A significant but weak negative
correlation between change in mean daily pressure and change in comfort
score between days was observed following adjustment for changes in
medication (r = 0.05, P = 0.026). No correlation was found between absolute
pressure change and change in comfort score or between absolute pressure
change and absolute change in comfort score. Currently, there is no evidence
supporting an association between barometric pressure and the degree of
discomfort experienced by
CKCS
with CM/SM. This appears
contrary to the experience of some individuals affected by these conditions.
A more objective assessment of a larger population of dogs is required to
determine whether or not barometric pressure has an influence on the comfort
of some or all
CKCS
with CM/SM. A further study by the same
authors is in development, aiming to investigate whether there is an
association between barometric pressure and comfort scores in people
affected by CM/SM. A larger sample size will be sought, allowing more
powerful statistical analysis of the results. This canine study has
functioned as a useful guide to methods of data collection and analysis that
can be used in future canine and human studies on this subject."
Prevalence and management of canine Chiari-like malformation/syringomyelia
recorded in primary-care practice in England
. Claire Thomas, Sandra
Sanchis-Mora, Ludovic Pelligand, Holger Volk, David Church, Paul McGreevy,
Peter Thomson, Dave Brodbelt, Dan O'Neill. BSAVA Conf. April 2015. Abstract
Pg. 446. Quote: "Chiari-like malformation / syringomyelia (CM/SM) describes
a developmental disorder that can cause pain and reduce quality of life.
This study aimed to explore clinical CM/SM cases in the veterinary
primary-care setting in order to improve our understanding of the impact of
the disorder on the overall canine population. The study included clinical
data on all dogs shared with the VetCompass primary-care project from
01/09/2009 to 13/06/2014. The case definition required a clinical diagnosis
with CM/SM confirmed using magnetic resonance imaging (MRI) in a clinically
affected dog. Possible cases were sourced from the free text and VeNom
diagnoses using key-search terms. Following manual verification, additional
information was extracted regarding clinical signs and therapeutic
management. Descriptive statistics were used to report CM/SM prevalence,
demography, clinical signs and therapy. A total of 59 CM/SM cases were
identified from 187,365 dogs, giving a prevalence of 0.03% (95% confidence
interval (CI): 0.02-0.04) across all dogs. The median (interquartile range)
age at diagnosis was 4.33 (0.33-11.58) years for the 34 incident cases
(57.62%). The most commonly affected breedtypes were
Cavalier King
Charles Spaniel (CKCS)
(37 dogs; 62.71%), King Charles Spaniels (12
dogs, 20.33%), crossbreed (3 dogs, 5.08.%), Yorkshire Terrier (2 dogs,
3.38%), and Affenpinscher, Pug, English Toy Spaniel, Jack Russell Terrier
and Chihuahua (1 dog, 1.69%). From the VetCompass population of 3,860 CKCSs,
this gave a breed prevalence of 0.96% (95% CI: 0.69-1.34) of MRI confirmed
cases. Practitioners also reported an additional 84 CKCS (2.18%, 95% CI:
1.75-2.70) suspected but unconfirmed cases. The most common clinical signs
associated with CM/SM were expression of pain (14 dogs, 23.72%),
characteristic CM/SM-associated motor signs (scratching or facial rubbing
without underlying skin disease) (11 dogs, 18.64%) and ataxia or weakness (7
dogs, 11.86%). Clinical signs were not specified for 16 cases (27.11%).
Analgesics (alone or in combination) were prescribed to 49 cases (83%). The
most common analgesic treatments were gabapentin (32 dogs, 65.3%), NSAIDs
(18 dogs, 36.7%), glucocorticoids (30 dogs, 26.3%) and tramadol (13 dogs,
26.5%). Practitioners reported 31 dogs (63.26%) showed apparent clinical
improvement following treatment. This study reported a low overall
prevalence of clinical CM/SM but higher prevalence in some individual
breeds. The high proportion of affected animals with clinical signs that can
variably reduce quality of life and that required analgesic therapy
highlight the welfare impact of the disorder on affected dogs."
Prevalence of disorders recorded in
Cavalier King Charles Spaniels
attending primary-care veterinary practices in England
. Jennifer F
Summers, Dan G O'Neill, David B Church, Peter C Thomson, Paul D McGreevy,
David C Brodbelt. Canine Genetics and Epidemiology. April 2015;2:4. Quote:
"This study used large volumes of health data from UK primary-care practices
participating in the VetCompass animal health surveillance project to
evaluate in detail the disorders diagnosed in a random selection of over 50%
of dogs recorded as
Cavalier King Charles Spaniels (CKCSs)
Confirmation of breed using available microchip and Kennel Club (KC)
registration data was attempted. Results: In total, 3624 dogs were recorded
as
CKCSs
within the VetCompass database of which 143 (3.9%)
were confirmed as KC-registered via microchip identification linkage of
VetCompass to the KC database. ... Microchip data were available in 1692
(46.7%) of the 3624 identified
CKCSs
. It was possible to
crosslink microchip data with KC-registration details in 143 of these dogs;
this represented 8.5% of all identified
CKCSs
with
microchip data, and 3.9% of all identified CKCSs. The remaining 3481 dogs
were classified as of unknown KC-registration status. The 52% randomly
selected sample of all identified
CKCSs
totalled 1875 dogs:
1800 with unknown and 75 with confirmed KC-registration status. These 1875
dogs were seen at 109 individual clinics during the study period, including
90 (83%) Medivet and 19 (17%) Vets4Pets sites located from north-east to
southern England. ...1875 dogs (75 KC registered and 1800 of unknown KC
status, 52% of both groups) were randomly sampled for detailed clinical
review. Clinical data associated with veterinary care were recorded in 1749
(93.3%) of these dogs. ... Median ages at first and last consultation were
4.0 and 5.25 years, respectively (ranges one month - 17.2 years for both age
measures). The most frequent coat colours were Blenheim (44.3%) and
tri-colour (30.8%) (Table 1). Of the 1521 dogs with more than one clinical
data entry, median time contributed to the study was 1.3 years (range 1 day
to 3.6 years). ... Magnetic Resonance Imaging (MRI) diagnoses of
syringomyelia (SM), canine Chiari malformation (CM) and both concurrently
were recorded in 19 (1.1%; 95% CI 0.7 -1.7%), 4 (0.2%; 95% CI 0.07 - 0.6%)
and 10 (0.6%; 95% CI 0.3 - 1.1%) of study dogs, respectively. Thus,
diagnosis of SM, CM or both was recorded in 33 (1.9%; 95% CI 1.3 - 2.7%) of
study dogs overall. Syringomyelia ranked 28th among specific diagnoses most
frequently recorded. Meaningful statistical comparison of diagnostic
frequencies between KC-registration status groups was not possible due to
the relatively low numbers of KC registered dogs identified. ...
MRI-confirmed diagnoses of either syringomyelia, CM or both were recorded in
approximately 2% of study dogs, with syringomyelia ranked 28th among the
most frequently recorded specific diagnoses. Including only those diagnoses
of either condition made with reference to MRI results (i.e. excluding those
suggested by clinical signs alone) could have underestimated the true level
in the population, as not all clinically suspicious cases underwent MRI
scanning. The sometimes vague nature of clinical signs may result in failure
to offer scanning in some cases, while reluctance (or financial limitations)
of owners to pursue MRI diagnosis may be the limiting factor in others. Bias
linked to comparative willingness to request high level diagnostic
investigation may be of particular relevance in breeding animals, if
breeders are more (or less) likely to volunteer breeding animals for MRI
through screening programs. The link between signs of SM/CM visible on MRI
and appearance of clinical signs can also be inconsistent, as not all dogs
with a visible syrinx on MRI display clinical signs at the time of imaging.
... Further work This work highlights the value of veterinary practice based
breed-specific epidemiological studies to provide targeted and
evidence-based health policies. Further studies using electronic patient
records in other breeds could highlight their potential disease
predispositions."
Medullary Position at the Craniocervical Junction in Mature
Cavalier
King Charles Spaniels
: Relationship with Neurologic Signs and
Syringomyelia
. S. Cerda-Gonzalez, N.J. Olby, E.H. Griffith.
J.Vet.Int.Med. April 2015. Quote: "Background: Medullary elevation (ie,
medullary kinking) at the craniocervical junction (CCJ) is reported in dogs
with Chiari-like malformations (CM), but its diagnostic criteria and
clinical relevance are unclear. Objective: To describe the position of the
medulla at the CCJ in mature
cavalier King Charles spaniels (CKCS)
and evaluate its relationship with clinical status and the presence of
syringomyelia. Animals:
Thirty-six CKCS
, 5-12 years of age
[median age: 9 years], including 16 asymptomatic dogs. Methods: Dogs were
assigned a neurologic grade; magnetic resonance imaging (MRI) of the CCJ
then was performed. The presence of a CM and syringomyelia was recorded and
syringomyelia severity was quantified. Medullary position was quantified
using the medullary kinking index, the elevation angle and obex position
relative to the foramen magnum. The relationship between medullary position
measures and presence and severity of neurologic signs and syringomyelia was
investigated. Results: Chiari-like malformation was found in 33 dogs; 26 of
them had syringomyelia. Mean medullary kinking index was 46.4% (SD, 10.3),
elevation angle was 132° (SD, 12) and obex position [caudodorsal-most border
of the fourth ventricle] was 3.5 mm (SD, 0.8). A higher medullary kinking
index was associated with the presence of neurologic signs (P = .0368). Obex
position was associated with the presence (P = .0018) and severity of
syringomyelia (P = .0164). ... In addition, an obex position measurement of
≤3.5 was sensitive (79%) and highly specific (90%) for the presence of
syringomyelia. ... Conclusions and clinical importance: There is a
significant association between medullary elevation and clinical signs,
whereas more caudal brainstem positions appear related to the presence of
syringomyelia."
Relationship between the clinical findings, MRI findings and the efficiency
of the prescribed drugs in
Cavalier King Charles Spaniels
with Chiari-like malformation and syringomyelia (CM/SM)
. Schuil,
D.A. Utrecht Univ. May 2015. Quote: "CM is a combination of malformation of
the hindbrain and the surrounding caudal cranial fosssa and a consequential
herniation of part of the cerebellum and brainstem into or through the
foramen magnum reported in small breed dogs. SM is currently defined as a
condition that results in the development of fluid-containing cavities
within the parenchyma of the spinal cord as a consequence of abnormal
cerebrospinal fluid movement. In this study the association between the
findings on MRI and the reported clinical signs were investigated, this was
done by using a hard copy survey about clincial signs observed by
cavalier king charles spaniel (CKCS)
owners that were scanned and
MRI findings of those
848 CKCS
[scanned in the
Netherlands]. ... There are two aims in this study; the first is to
investigate the association between the findings on magnetic resonance
imaging (MRI) and the reported clinical signs observed by the individual
owners, the second is to do a retrospective study to investigate the effect
of prescribed drugs. ... One of the 844 dogs that were scanned did not have
chiari malformation. 704 dogs were diagnosed with chiari malformation grade
2 (CM2) and 139 dogs were diagnosed with chiari malformation grade 3 (CM3).
... 555 of the 844 scanned dogs did not have syringomyelia. 9 dogs were
diagnosed with syringomyelia grade 1 (SM1), 106 dogs were diagnosed with
syringomyelia grade 2 (SM2), 10 dogs were diagnosed with syringomyelia grade
3 (SM3) and 164 dogs were diagnosed with syringomyelia grade 4 (SM4). ...
233 completed surveys were returned. According to the owners 45 dogs have
complaints (19,3%) and 188 dogs do not have complaints (80,7%). ... It appeared that there were no significant relationships
between the observed clincial signs and the grade of CM/SM found on the MRI
scans. The owners were also asked about the efficiency of the prescribed
drugs in their dogs, because of a lack of response, no conclusions could be
drawn from this question. ... The aim of this study was to find a
relationship between the clinical findings, MRI findings and the efficacy of
the prescribed drugs in CKCS with CM/SM. Unfortunately only a few surveys
were returned. A total of 45 surveys were completely filled in by owners
from CKCS with complaints. Hence, the results are not sufficient enough to
fully explore associations between clinical signs and the grade of SM (the
MRI findings). Furthermore, as all dogs suffer from either CM 2 or 3, it is
not possible to extrapolate for CM 0 to CM 3 and the clinical signs."
Comparison of the Relationship between Cerebral White Matter and Grey Matter
in Normal Dogs and Dogs with Lateral Ventricular Enlargement
Martin J. Schmidt, Steffi Laubner, Malgorzata Kolecka, Klaus Failing,
Andreas Moritz,  Martin Kramer, Nele Ondreka. PLoS ONE 10(5): e0124174.
May 2015. Quote: "Large cerebral ventricles are a frequent finding in brains
of dogs with brachycephalic skull conformation, in comparison with
mesaticephalic dogs. It remains unclear whether oversized ventricles
represent a normal variant or a pathological condition in brachycephalic
dogs. There is a distinct relationship between white matter and grey matter
in the cerebrum of all eutherian mammals. The aim of this study was to
determine if this physiological proportion between white matter and grey
matter of the forebrain still exists in brachycephalic dogs with oversized
ventricles. The relative cerebral grey matter, white matter and
cerebrospinal fluid volume in dogs were determined based on
magnetic-resonance-imaging datasets using graphical software. In an analysis
of covariance (ANCOVA) using body mass as the covariate, the adjusted means
of the brain tissue volumes of two groups of dogs were compared. Group 1
included 37 mesaticephalic dogs of different sizes with no apparent changes
in brain morphology, and subjectively normal ventricle size. Group 2
included 35 brachycephalic dogs [including
7 cavalier King Charles
spaniels
, 4 of which were diagnosed with syringomyelia] in which subjectively enlarged cerebral
ventricles were noted as an incidental finding in their
magnetic-resonance-imaging examination. Whereas no significant different
adjusted means of the grey matter could be determined, the group of
brachycephalic dogs had significantly larger adjusted means of lateral
cerebral ventricles and significantly less adjusted means of relative white
matter volume. This indicates that brachycephalic dogs with subjective
ventriculomegaly have less white matter, as expected based on their body
weight and cerebral volume. Our study suggests that ventriculomegaly in
brachycephalic dogs is not a normal variant of ventricular volume. Based on
the changes in the relative proportion of WM and CSF volume, and the
unchanged GM proportions in dogs with ventriculomegaly, we rather suggest
that distension of the lateral ventricles might be the underlying cause of
pressure related periventricular loss of white matter tissue, as occurs in
internal hydrocephalus. ... The influence of ventriculomegaly on brain
function in dogs is unclear. Detailed behavioural studies of the impact of
WM loss on the full functional integration of the nervous system are
necessary to clarify whether ventriculomegaly might be an indication for CSF
shunting procedures in dogs."
Dorsal Compressive Atlantoaxial Bands and the Craniocervical Junction
Syndrome: Association with Clinical Signs and Syringomyelia in Mature
Cavalier King Charles Spaniels
. S. Cerda-Gonzalez,
N. J. Olby, E. H. Griffith. J.Vet.Int.Med. May 2015;29(3):887-892. Quote:
Background: Dorsal compressive lesions at the atlantoaxial junction (ie, AA
bands) occur in dogs with Chiari-like malformations (CMs), but their
clinical relevance is unclear. Objective: Investigate the influence of AA
bands on clinical status and syringomyelia (SM) in mature
cavalier
King Charles spaniels (CKCS)
. Animals: Thirty-six
CKCS
5-12 years of age, including 20 dogs with neuropathic pain. Methods: Dogs
were examined and assigned a neurologic grade. Magnetic resonance imaging
(MRI) of the craniocervical junction was performed with the craniocervical
junction extended and flexed (ie, normal standing position). Imaging studies
were assessed for the presence of an AA band, CM, SM or some combination of
these findings. Band and SM severity were quantified using an objective
compression index and ordinal grading scale, respectively. Results: Of 36
CKCS
imaged, 34 had CM. Atlantoaxial bands were present in
31 dogs and were more prominent in extended than flexed positions.
Syringomyelia was found in 26 dogs, 23 of which also had AA bands. Bands
were associated with both the presence (P = .0031) but not the severity (P =
.008) of clinical signs whereas their presence was associated with both the
presence and severity of SM (P = .0147, P = .0311, respectively). Higher
compression indices were associated with more severe SM (P = .0137).
Conclusions: Prevalence of AA bands in older
CKCS
is high.
Positioning of dogs in extension during MRI enhances the sensitivity of the
study for detecting this important abnormality. There were significant
associations among AA bands, clinical signs, and SM in dogs with CM;
additional work is needed to understand whether or not this relationship is
causal. (See also,
Erratum published March 2020 here.
MRI
characteristics of atlanto-axial subluxation in 42 dogs
. Kathryn
Bray, Simon R. Platt, Marc Kent, Allison Haley, Jill Narak, Amy W. Hodshon,
Natasha J. Olby, Shannon P. Holmes. J.Vet.Int.Med. July 2015;29(4):1122-1256;N-19. Quote: "The purpose of this retrospective study was to describe
the magnetic resonance imaging (MRI) characteristics of canine atlanto-axial
(AA) subluxation and to identify associations with neurologic deficits. A
multicenter review of the medical records and MR images of dogs with a
diagnosis of AA subluxation was conducted. Signalment, neurologic grade,
time to onset of signs, and MRI characteristics were recorded. The evaluated
MRI characteristics included (1) spinal cord compression, (2) degree of
joint subluxation, (3) integrity of odontoid ligamentous structures, (4)
presence of a dens, (5) presence of cord signal intensity, and (6) presence
of syringohydromyelia, hydrocephalus, and Chiari-like malformation. A
control population of age and breed matched dogs with normal AA junctions
were also evaluated. Reviewers were blinded to affected status. MR images of
42 dogs affected with AA subluxation were reviewed and compared to 26
control dogs. The majority of affected dogs were Yorkshire Terriers (47.5%).
The median age was 27 months. The median weight was 2.7 kg. The control
population had a median age of 96 months, and a median weight of 4.7 kg; the
most common breeds were Maltese (18.5%) and Pomeranian (18.5%). 28% of dogs
were affected less than 1 week, 30% were affected between one week and one
month, and 42% were affected for greater than 1 month. Neurologic grade
ranged from 1 (spinal pain only) to 5 (tetraplegic without nociception), but
50% of affected dogs were ambulatory tetraparetic (grade 2). Associations of
MRI characteristics with affected status of dog (AA subluxation or control)
and neurologic grade were assessed by logistic regression. Associations of
MRI characteristics with each other was performed using Spearman and Pearson
correlations, student t-tests, analysis of variance and Kruskal-Wallis tests
as appropriate. No differences were noted between the affected and control
dogs with respect to the presence of syringohydromyelia, hydrocephalus and
Chiari-like malformation. Significant differences between control and
affected dogs were noted with respect to presence of a dens, apical
ligament, and transverse ligament. The presence of cord signal intensity was
associated with affected status, as was increased AA joint cavity size and
percentage crosssectional cord compression at the level of the dens and
mid-body C2. No associations were found between cord compression, appearance
of the dens or cord signal intensity and neurologic grade of affected dogs.
There was an association between the presence of cord signal intensity and
increased joint cavity size. There was no association between dens
appearance and cord signal intensity. Dens abnormalities were associated
with greater subluxation distance and odontoid ligament absence was
associated with increased joint cavity size. Dogs affected by AA subluxation
do not have a higher incidence of Chiari-like malformation,
syringohydromyelia, or hydrocephalus than control dogs, and their neurologic
grade is not associated with MRI findings. However, lack of a dens and/or
odontoid ligaments are associated with larger subluxations."
Chiari-tyyppinen Epamuodostuma Ja Syringomyelia: Esiintyminen Muilla
Roduilla Kuin
Cavalier Kingcharlesinspanielilla
[Chiari
malformation and syringomyelia in breeds other than the
Cavalier
King Charles Spaniel
. Johanna Forsgård. Univ. of Helsinki
thesis. June 2015. Quote: ""The aim of this study was to find out how much
breeds other than the
Cavalier King Charles Spaniel
taken
to the Helsinki University Teaching Hospital for head MRI scans showed
Chiari-like malformation and Syringomyelia. Furthermore, the purpose was to
gather current knowledge of the disease pathophysiology, symptoms,
diagnosis, treatment, genetics and breeding. On the basis of my results,
Chiari-like malformation seems to occur fairly commonly in other breeds,
regardless of the size or shape of the skull. Syringomyelia, in turn, was
seen much less. It would thus appear that syringomyelia is not always
related to Chiari-like malformation, but perhaps there are other factors
required. The results also question the studies with control groups have
been used in France and labradors, because even these breeds were found to
have Chiari-like malformation."
Attempts to breed out chiari-like malformation: is a cross the answer?
Susan Knowler, Henny van den Berg, Eric Noorman, Roberto La Ragione, Clare
Rusbridge. J.Vet.Int.Med. July 2015;29(4):1257-1283. Quote: "Chiari-like malformation (CM)
and syringomyelia (SM) are complex inherited disorders observed most
commonly in toy breed dogs and can cause a significant loss in quality of
life though pain and disability. Brachycephalicism is a risk factor and it
has been suggested that crossbreeding with a different breed/s then
backcrossing may produce individuals free of disease. This two and a half
year project took advantage of a cross between a mesaticephalic normal
Australian terrier and CM affected Griffon Bruxellois (GB) with subsequent
backcrossing to a GB to investigate the inheritance and phenotype of these
conditions and a means of reducing the incidence of CM and risk of SM. The
study cohort comprised 2 control dogs (CM affected Australian terrier and
unrelated GB without CM) and a single of family of 29 dogs, 12 of which were
used in 8 different mating combinations resulting in 19 progeny. T1-weighted
sagittal DICOM images were analyzed for traits (2 angles, 2 lines and a
"best fit" circle diameter) shown previously to have the greatest
significance for CM in the GB. The quantitative findings in this study
revealed these traits to be significant for CM-affectedness. Furthermore the
external phenotypes showed that by outcrossing breed types and selecting
appropriate conformation characteristics in the F1 generation, it is
possible to regain the GB breed standard in the F2 generation and reduce the
degree of CM. However this is dependent on careful selection of conformation
and screening for CM and SM at 1 year of age. The 4 dogs affected with SM in
the study all exhibited reduced caudal skull development compared to their
relatives. We showed that traits on MR images were useful to distinguish the
phenotype and these exhibited segregation and may be additive towards the
severity of CM. It suggests such traits might be useful to quantify the
condition and the risk to SM. We propose that grading of CM takes account of
quantitative traits that can be used in Estimated Breeding Values (EBV) to
assist breeders with their mate selections. Such a system will have to be
verified to ensure appropriateness for all breeds at risk."
Low-Field Magnetic Resonance Imaging and Multislice Computed Tomography for
the Detection of Cervical Syringomyelia in Dogs
. K. Kromhout, H.
van Bree, B.J.G. Broeckx, S. Bhatti, S. De Decker, I. Polis, I. Gielen.J.
Vet. Int. Med. September 2015;29(5):1354-1359. Quote: "Background: Syringomyelia (SM) is
defined as the presence of fluid-containing cavities within the parenchyma
of the spinal cord. Sagittal magnetic resonance (MR) images have been
described as the preferred technique for visualizing SM in dogs and humans.
Objective: To investigate whether computed tomography (CT) can be used to
diagnose SM. Animals: Thirty-two client-owned dogs referred for
investigation of the cervical spine on magnetic resonance imaging (MRI) and
CT [including 12
cavalier King Charles spaniels - CKCSs
].
Methods: Two reviewers retrospectively analyzed sagittal and transverse
T1-weighted spin echo (T1WSE) MR images and CT images from each dog for the
presence of SM and, if SM was present, the width (mm, syrinx width [SW]) was
measured. The results were analyzed statistically. Results: ... Results of
this study demonstrate that low-field MR and multislice CT imaging provide
comparable information regarding the presence of SM. ... For the presence of
SM there was a moderate interobserver agreement for MR (81%, κ = 0.54) and
almost perfect agreement for CT (94%, κ = 0.87). There was a moderate
intramodality agreement for both observers (observer 1 81%, κ = 0.59;
observer 2 81%, κ = 0.57). For measurement of SW the repeatability was the
best on the midsagittal T1WSE images (95% repeatability coefficient <0.52
mm) and the reproducibility was the best on midsagittal images in both
modalities (95% limits of agreement −0.55-0.45; P = 0.002). Conclusion and
Clinical Importance: Both techniques can be used to detect SM. Midsagittal
MR and CT images are best used for measuring SW. ... The central canal is
normally just appreciable on MR images and not visible in normal
circumstances on CT images. However, any dilatation of the central canal
should be considered abnormal. Hence, the detection of smaller dilatations
on both MR and CT is important as progressive central canal dilatation is a
precursor of syrinx formation. Furthermore, results of a previous study
suggest that SW progresses with time in
CKCS
. ...
This
study did not find an association between the detection of a small
dilatation and use of technique.
[Figure 3.]
The difference in
detection and measurement can be attributed to the experience of the
observer and the presence of several of the artifacts mentioned earlier.
Overall, we conclude that SM is consistently identified by different
observers on CT and on MRI. In addition, the results of this study suggest
that when a syrinx is detected the highest agreement is present for
measuring SW on both the midsagittal MR and CT images. Syringomyelia and SW
have been shown to explain at least some of the clinical signs in dogs. As
CT scanners are more readily available in veterinary practices compared with
MRI equipment, CT can be used as a diagnostic tool for SM when MRI is not
available. Cerebellar herniation is consistently identified by different
observers on CT and on MR images of
CKCS
. Bearing this in
mind, we can conclude, that CT can be used as an alternative imaging
technique for Chiari-like malformation/SM in
CKCS
when MRI
is not available. We emphasize that, at the current time, CT cannot replace
MRI as the standard screening technique for the detection of SM in
CKCS
for breeding purposes, more specific for the detection of the
presyrinx state." See also,
"Low-Field MRI and Multislice CT for the Detection of Cerebellar
(Foramen Magnum) Herniation in Cavalier King Charles Spaniels"
, by
the same team of researchers.
Comparison of gabapentin versus topiramate on clinically affected dogs with
Chiari-like malformation and syringomyelia
. I. N. Plessas, H. A.
Volk, C. Rusbridge, A. E. Vanhaesebrouck, N. D. Jeffery. Vet. Rec. September 2015;177:288. Quote: "To date there is no evidence-based data for efficacious
treatment of neuropathic pain in dogs with Chiari-like malformation (CM) and
syringomyelia (SM). ... The aim of this study was to compare prospectively,
in a cross-over trial, the effect of gabapentin versus topiramate, as an
adjunctive treatment to carprofen, on QoL of clinically affected
CKCS
with CM/SM, as assessed by the owners using a visual analogue
scale (VAS), and record any adverse effects.
Forty Cavalier King
Charles spaniel dogs
were included in the trial from three
different referral hospitals in the UK. ... A visual analogue scale (VAS)
was used to assess the QoL: (1) on day 0; (2) after 1 week of carprofen
only; (3) after 2 weeks on carprofen and gabapentin; and (4) after 2 weeks
on carprofen and topiramate. No significant difference was observed between
VAS after gabapentin or topiramate (P=0.91). However, an improvement in QoL
was observed when gabapentin was compared with baseline (P=0.009), but not
for topiramate. ... In this prospective, randomised, cross-over study in
clinically affected
CKCS
with CM/SM no significant
difference was observed on their QoL when gabapentin was compared with
topiramate. Data also suggests that the addition of either of these two
drugs may be more effective than carprofen alone. Sedation was the most
common adverse effect of both drugs with the addition of inappetence for
topiramate; however the adverse effects associated with the latter drug were
more severe. In conclusion, gabapentin's more favourable adverse effect
profile may be more suitable than topiramate in dogs experiencing NeP, but
further placebo-controlled prospective studies will be needed to better
establish the comparative effect of these drugs. ... Perhaps the more
favourable side effect profile of the former makes it more suitable for the
treatment of neuropathic pain associated with CM/SM but further
placebo-controlled trials are required to assess the efficacy of these
drugs."
Association between the identification of a syrinx in asymptomatic
cavalier King Charles spaniels
and the subsequent development of
clinical syringomyelia
. A. Vanhaesebrouck, L. Doyle, M. Holmes, T.
Williams, E. Ives. 27th ESVN-ECVN Symposium. J.Vet.Int.Med. August 2015;
ESVN-ECVN Abstracts p.12. Quote: "The aim of this study was to determine
whether the presence of a syrinx on pre-breeding MRI screening in an
asymptomatic
Cavalier King Charles Spaniel
(CKCS)
could predict the likelihood of a dog developing clinical signs consistent
with syringomyelia in later life. Owners of
CKCS
that were
screened for the presence of a syrinx on MRI between 2006 and 2009 were
asked to complete a questionnaire regarding signalement, general health and
common syringomyelia symptoms in 2013. Only dogs that were reported to be
asymptomatic at the time of MRI were included, and dogs with concurrent
diseases were excluded from the study. MRI scans of the craniocervical
region were reviewed in random, blinded fashion. The data were analyzed by
binary logistic regression. Seventy-nine questionnaires fulfilled the
inclusion criteria. Dogs were scanned at a median age of 2.6 years [IQR
2.2-3.5 years], with a syrinx identified on MRI in 32% of dogs. Sixteen
percent of dogs developed clinical signs compatible with syringomyelia, with
a median age at onset of 5 years [IQR 4-7 years]. A higher proportion of
dogs with a syrinx visible on MRI screening developed clinical signs
consistent with syringomyelia in later life (36%), when compared to dogs
without a visible syrinx (7%) (Hazard ratio, 6.1; p = 0.003). None of the
other variables entered in the logistic regression analysis reached
statistical significance. The presence of a syrinx on MRI screening appears
to represent a risk factor for the subsequent development of clinical signs
consistent with syringomyelia in
CKCS
."
Pulse wave myelopathy: An update of an hypothesis highlighting the
similarities between syringomyelia and normal pressure hydrocephalus
Grant A. Bateman. Med. Hypotheses. September 2015. Quote: "Most hypotheses
trying to explain the pathophysiology of idiopathic syringomyelia involve
mechanisms whereby CSF is pumped against a pressure gradient, from the
subarachnoid space into the cord parenchyma. On review, these theories have
universally failed to explain the disease process. A few papers have
suggested that the syrinx fluid may originate from the cord capillary bed
itself. However, in these papers, the fluid is said to accumulate due to
impaired fluid drainage out of the cord. Again, there is little evidence to
substantiate this. This proffered hypothesis looks at the problem from the
perspective that syringo-myelia and normal pressure hydrocephalus are almost
identical in their manifestations but only differ in their site of effect
within the neuraxis. It is suggested that the primary trigger for
syringomyelia is a reduction in the compliance of the veins draining the
spinal cord. This reduces the efficiency of the pulse wave dampening,
occurring within the cord parenchyma, increasing arteriolar and capillary
pulse pressure. The increased capillary pulse pressure opens the
blood-spinal cord barrier due to a direct effect upon the wall integrity and
interstitial fluid accumulates due to an increased secretion rate. An
increase in arteriolar pulse pressure increases the kinetic energy within
the cord parenchyma and this disrupts the cytoarchitecture allowing the
fluid to accumulate into small cystic regions in the cord. With time the
cystic regions coalesce to form one large cavity which continues to increase
in size due to the ongoing interstitial fluid secretion and the hyperdynamic
cord vasculature."
Treating Chiari-like malformation and
syringomyelia in dogs
. C. Stalin. Vet. Rec. September 2015;177:286-287.
Quote: "Chiari-like malformation and syringomyelia is well recognised in
Cavalier King Charles spaniels
. Syringomyelia is
characterised by cavitation of the spinal cord leading to disruption of the
decussating spinothalamic fibres. In people with syringomyelia, pain is a
prominent feature in 50 to 90 per cent. Patients typically present with
complaints of radicular pain, interscapular pain, and/or central cord pain.
In addition to the more common clinical pain syndromes, approximately 40 per
cent of patients with syringomyelia experience significant dysaesthetic
pain, which is variously described as a burning sensation, pins and needles,
or stretching of the skin (Todor and others 2000). Chronic pain resulting
from injury to either the peripheral or central nervous system is referred
to as neuropathic pain. Neuropathic pain in animals is difficult to
recognise as, unlike people, they are not able to voice the discomfort and
abnormal sensations. However, owners of
Cavalier King Charles
spaniels
with syringomyelia will report a typical history of
yelping, scratching behaviour, apparent discomfort or avoidance of being
touched over the ear, neck, shoulder or sternum or abnormal head posture (
Rusbridge
and others 2007
). It is therefore assumed that these dogs are suffering
from neuropathic pain similar to that described by their human counterparts.
In order to establish appropriate medical therapy in dogs with
syringomyelia, our justification needs to be based on more than anecdotal
evidence in individual dogs. On this basis,
Rusbridge and Jeffery (2008)
suggested the need for a mutilcentre approach to rationalise medical
management of syringomyelia. Therefore, seven years later,
Plessas
and others (2015)
, in a paper summarising the results of a prospective,
randomized cross-over trial to assess the efficacy of gabapentin versus
topiramate as an adjunctive treatment to carprofen in clinically affected
dogs wth syringomyelia. Gabapentin and topiramate are both anticonvulsant
medications that have been used to treat neuropathic pain in people, with
gabapenin problably being the more effective of the two (Finnerup and others
2005, Khoromi and others 2005). Despite the lack of evidence-based data,
gabapentin is widely used in veterinary medicine to treat suspected
neuropathic pain."
Atlantooccipital Overlap and Other Craniocervical Junction Abnormalities in
Dogs
. Catherine A. Loughin, Dominic J. Marino. Vet. Clin. Small
Animal. November 2015. Quote: "Craniocervical junction abnormalities (CJA)
are being recognized more frequently in veterinary patients. The term CJA is
an umbrella term for a variety of malformations that occur in the
craniocervical region. Chiari-like malformation (CLM) is commonly diagnosed
in small-breed dogs, and is defined as an abnormal-shaped supraoccipital
bone resulting in rostral compression of the caudal aspect of the
cerebellum. This is the most commonly diagnosed CJA, but other malformations
include atlantooccipital overlapping (AOO), atlantoaxial instability,
occipitoatlantoaxial malformation (OAAM), atlantoaxial dural bands, and dens
abnormality. Determining the structural cause of cerebellar compression is
difficult on MRI because of poor bone visualization, but with the addition
of computed tomography (CT) and three-dimensional reconstruction these
structural abnormalities become easier to recognize. The term craniocervical
junction abnormality (CJA), as used in human medicine, serves as an umbrella
term for a variety of malformations that occur in the craniocervical region.
MRI of craniocervical junction abnormalities with CT imaging are necessary
to fully evaluate CJAs. Most dogs with atlantooccipital overlapping (AOO)
respond temporarily to medical management. Like CLM/SM, we often consider
AOO to be a surgical disorder.
What is Chiari Malformation (COMS)
Jason King. Live Oak Vet.
Neuro. December 2015. Quote: "Chiari malformation is the term used in human
medicine that equates in veterinary medicine to Caudal Occipital
Malformation Syndrome, COMS. The most commonly affected breed with COMS is
the Cavalier King Charles Spaniel. ... COMS is a condition where the base of
the skull in the dog is abnormally shaped. This leads to a more 'rounded
skull' and, in turn, causes the part of the brain at the base of the skull
(the cerebellum) to be 'crowded'. Because this skull defect is present at
birth and through the growth phase of the puppy, once the dog reaches
adulthood, the skull changes are static and don't change. But the
after-effects are progressive. You see, COMS is associated with another
condition that takes place in the spinal cord 'downstream' from the skull in
the dog's neck. This condition is called syringohydromyelia or SM. SM is a
progressive degenerative condition in the spinal cord that can happen
anytime the flow of spinal fluid is disrupted. The part of the spinal cord
that is towards the chest of a person or animal carries information from the
brain to the body, instructions on how to move. The part of the spinal cord
towards the back of the person or animal carries information from the body
to the brain, sensory information if you will. Interestingly enough, SM
almost always forms in the sensory part of the spinal cord. So it leads to
abnormal sensations rather than weakness or abnormal movments. That means
that dogs with SM manifest some very odd and quite varied behaviors
secondary to the abnormal sensations that their spinal cord is causing them
to feel. Imagine, that every time you got excited your toes began to itch
and burn, your ear began to feel hot, or your arm became numb and tingly...
The most striking manifestation of this abnormal sensation is called
'phantom scratching'. In this situation, dogs will begin to scratch 'at'
their ear, but just a little bit off to the side. Almost as if they were
scratching the air! Diagnosis of COMS and SM requires an MRI. No other tests
are able to definitively diagnose this condition. There are other tests that
have been used to support the diagnosis though, including BAER hearing
tests, CT scans, ultrasound, and even infrared imaging. Treatment for COMS
is sometimes medical, and sometimes surgical. There are several drugs that
can be used to help control the condition, and surgery can be very
successful (depending on how one defines 'success')."
Computer simulation of the canine spine: the effects of increased spinal
cord motion on the developemnt of Syringomyelia
. R. Lloyd, S.
Cirovic, J. Jovanovik, H. Volk, C. Rusbridge. ESVN Abstract J. Vet. Int.
Med. December 2015. Quote: Syringomyelia is a disorder characterized with
the presence of fluid-filled cavities in the spinal cord. The condition
occurs in both humans and animals. The mechanism(s) of cavity formation are
not clear, leading to limited treatment. Current theories are based on the
assumption that abnormities in the circulation of the cerebrospinal fluid
(CSF) generates pressures that drive the fluid into the cord. A finite
element model was constructed using geometry extracted from MRI scans of a
Cavalier King Charles spanie
l with syringomyelia, to
explore possible mechanisms of syrinx formation. The model included the
spinal cord, subarachnoid space (SAS), dura mater, and the epidural space.
It has been shown in patients with restricted CSF flow, that there is
exaggerated movement of the spinal cord during the cardiac cycle. This
motion was applied to the cranial end of the spinal cord of the model. The
peak longitudinal and radial pressure differences in the SAS oscillated
between −22.3 to +90.0 Pa, and −100 to +100 Pa, respectively. Low-amplitude
cyclic shear stresses were present in the cervical spinal cord (C2 - C6),
where the cavities typically originate. In conclusion it was proposed that
the CSF pressure gradients are unlikely to cause fluid movement into the
cord, sufficient to generate syrinxes. On the other hand, although the shear
stress in the cord is low, its location and cyclic nature indicates the
possibility that this may be the factor that generates the initial tissue
damage, which eventually leads to the formation of syrinxes. (See also this
March 2018 article
by the same research team.)
Chiari-Like Malformation with Syringomyelia in the Small Breed Dogs:
Prognosis Evaluation after Surgical Management (Case Report)
Sung-Su Park, Hyun-Ju Kim, Jung Min Ryu, Ho Jae Han. Global Veterinaria.
2015;15(1):129-132. Quote: Small breed dogs were visited for the evaluation
of neurologic deficits. On neurologic examination, all dogs were showed
hyperesthesia, pain, neck stiffness or ataxia. After diagnosis by magnetic
resonance imaging (MRI) dogs had cranial cervical decompression with
durotomy. These dogs had the durotomy patched with autologous subcutaneous
fat. The clinical signs of all dogs improved postoperatively. This case
report demonstrates to evaluate success of cranial cervical decompression
for management of canine chiari-like malformation with syringomyelia
(CM/SM). ... In this report, cranial cervical decompression surgery for
CM/SM has low mortality and morbidity and in dogs with pain the procedure
can improve quality of life; however, syrinx collapse seemingly does not
occur and resolution may be related to other factors involved in the
development and/or persistence of syringomyelia. Surgical management may be
regarded as not resolve the syringomyelia, but prevent the deterioration of
syringomyelia. Therefore, the timing of surgical management is very
important for the good prognosis. Further, based on these dogs, it is
suggested that to properly evaluate the success of any surgical technique
for CM/SM that postoperative MRI scans be performed because clinical
improvement does not necessarily imply radiographic improvement.
RETURN TO TOP
2016
Cranial suture closure in domestic dog breeds and
relations to skull morphology
. Madeleine Geiger, Sinah Haussman.
Anatomical Record. January 2016. Quote: "Bulldog-type brachycephalic
domestic dog breeds are characterised by a relatively short and broad skull
with a dorsally rotated rostrum (airorhynchy). Only few is known about the
association between a bulldog-type skull conformation and peculiar patterns
of suture and synchondrosis closure in domestic dogs. In this study, we aim
to explore breed-specific patterns of cranial suture and synchondrosis
closure in relation to the prebasial angle (proxy for airorhynchy and thus
bulldog-type skull conformation) in domestic dogs. For this purpose, we
coded closure of 18 sutures and synchondroses in 26 wolves - the wild
ancestor of all domestic dogs - and 134 domestic dogs comprising 11 breeds.
Comparisons of the relative amount of closing and closed sutures and
synchondroses (closure scores) in adult individuals showed that bulldog-type
breeds have significantly higher closure scores than non-bulldog-type breeds
and that domestic dogs have significantly higher closure scores than the
wolf. We further found that the prebasial angle is significantly positively
correlated with the amount of closure of the basispheno-presphenoid
synchondrosis and sutures of the nose (premaxillo-nasal and maxillo-nasal)
and the palate (premaxillo-maxillary and interpalatine). Our results show
that there is a correlation between patterns of suture and synchondrosis
closure and skull shape in domestic dogs, although the causal relationships
remain elusive."
Magnetic resonance imaging-based measures of atlas position: Relationship to
canine atlantooccipital overlapping, syringomyelia and clinical signs
S. Cerda-Gonzalez, K.F. Bibi, A.T. Gifford, E.L. Mudrak, P.V. Scrivani. Vet.
J. March 2016;209:133-138. Quote: "Canine atlantooccipital overlapping (AOO) is
characterized by a decreased distance between the dorsal arch of the atlas
and the supraoccipital bone. Current diagnostic criteria for this condition
are subjective and clinician-dependent; objective criteria are needed to
allow a reliable and reproducible diagnosis in clinical and research
settings and assess clinical significance. We propose four standardized
MRI-based measurements to objectively assess the proximity of the atlas to
the foramen magnum. Inclusion criteria for dogs in this study were
bodyweight <15 kg, age >5 months, and availability of a complete MRI study
performed with the craniocervical junction in extension. Exclusion criteria
were space-occupying lesions and poor image quality (i.e. unclear bony
margins). Measurements also included blinded determinations of skull type,
presence of craniocervical junction anomalies and presence and severity of
syringomyelia. Clinical status at the time of imaging was noted.
Measurements were obtained in 271 dogs; these were reproducible and
reliable. Findings varied by skull type: dolichocephalic dogs had smaller
foramen magnum, whereas brachycephalic dogs had more cranially and dorsally
positioned atlas bodies in comparison to the other skull types. Measurements
also increased with increases in bodyweight. This study demonstrated a close
association between AOO, syringomyelia and clinical signs. Toy and small
breed dogs (including
Cavalier King Charles spaniels
showed higher than previously reported prevalence of AOO; its occurrence was
also associated with lower bodyweights within the study population of <15 kg
toy/small breed dogs. ...
CKCS
were more likely (86%) than
non-CKCS (44%) to have AOO."
Evaluation of the effect of oral omeprazole on canine cerebrospinal fluid
production: A pilot study
. M. Girod, F. Allerton, K. Gommeren, A.C.
Tutunaru, J. de Marchin, I. Van Soens, E. Ramery, D. Peeters. Vet. J.
March 2016;209:119-124. Quote: "Administration of omeprazole by ventriculo-cisternal
perfusion and/or intravenously has been shown to decrease cerebrospinal
fluid (CSF) production in dogs and rabbits. Oral omeprazole has consequently
been recommended to reduce CSF production in dogs with conditions in which
clinical signs may be attributable to an accumulation of CSF in the central
nervous system (e.g. hydrocephalus, syringomyelia). The albumin quotient
(QAlb), the ratio between CSF and serum albumin concentration, has been
proposed as a reliable means to evaluate CSF production; decreasing CSF
production should cause an increase in QAlb. The aims of this study were to
assess the effect of oral administration of omeprazole on QAlb in dogs and
to compare two methods to assess CSF albumin concentration. Fifteen healthy
Beagle dogs received omeprazole (1.2 mg/kg/day) orally for 14 days; CSF and
blood were obtained before and after treatment. CSF albumin concentrations
were evaluated by nephelometry and high-resolution protein electrophoresis.
Regardless of the method used for measuring albumin, QAlb did not change
significantly following oral omeprazole administration, suggesting that CSF
production in healthy dogs may not be affected by chronic oral therapy with
omeprazole."
Chiari-Like Malformation and Syringomyelia
. Ates Barut.
Balkanvets.com January 2016. Quote: "Chiari-like malformation is a
hereditary condition and first described in
king charles cavalier
spaniels
and altough several other small breeds can become effected
king charles cavaliers
are the most common breed effected
by the disease. The other reported breeds are; Griffon, Miniature poodle,
Yorkshire terrier, Maltese, Chihuahua, Bichon frise, Staffordshire terrier,
Pug, Shih Tzu, Dachsund, Pincher, French bulldog, Jack Russel Terrier,
Pekingese and Boston terriers. Affected patients has a kind of cerebellar
compression and narrowing around foramen magnum and cervicomeduller
junction. ... As a result chiari-like malformation and syringomyelia is one
of the most important breed predispositions of veterinary medicine and
although the disease is reported in several other breeds it creates a very
important clinical problem among king charles cavalier population. Most of
the patients with syringomyelia can live whole their lives with very mild
symptoms within a normal life expectancies but some patients will have
cervical myelopathy, cerebellovestibüler dysfunction and multifocal central
nervous system dysfunction. Pain and life quality is the main concern and
criteria for treatment. Patients with obvious neurological signs and pain
and non-responsive to pain managment therapies are candidates for surgery.
Foramen magnum decompression and syringo-subarachnoid shunt application are
the two surgical procedures described to reorganize normal cerebrospinal
fluid flow and drain syrinx from its cavity."
Chiari-like
Malformation
. Catherine A. Loughin. Vet. Clin. Small Animal.
March 2016;46(2):231-242. Quote: "Chiari-like malformation (CLM) is a condition of the
craniocervical junction in which there is a mismatch of the structures of
the caudal cranial fossa (CCF), often causing the cerebellum to herniate
into the foramen magnum. Affected dogs have a smaller CCF with relatively
more brain parenchyma within the fossa compared to unaffected dogs. This
smaller CCF leads to cerebellar compression and herniation through the
foramen magnum, kinking of the medulla, and disruption of cerebrospinal
fluid (CSF) at this junction. This malformation is found most commonly in
the
Cavalier King Charles spaniel (CKCS),
is inherited, and
is thought to affect as much as 95% of the population. However, CLM has also
been diagnosed in the Griffon Bruxellois and many other small breed dogs and
is also analogous to Chiari type 1 malformation in humans. Chiari-like
malformation is a condition in which there is a relatively small caudal
cranial fossa volume with associated crowding of the brain parenchyma.
Chiari-like malformation is diagnosed on MRI by identifying cerebellar
herniation, cerebellar compression, and attenuation of cerebrospinal fluid,
but kinking of the medulla, ventriculomegaly/hydrocephalus, and
syringomyelia are also noted in many dogs. Some patients respond favorably
to medical management; foramen magnum decompression with a durotomy is the
surgical treatment of choice in improving or resolving clinical signs in
dogs with Chiari-like malformation."
Managing Neuropathic Pain in Dogs
. Sarah A. Moore. Frontiers in
Vet. Sci. February 2016. Quote: "Disorders of the somatosensory system such
as neuropathic pain are common in people with chronic neurologic and
musculoskeletal diseases, yet these conditions remain an underappreciated
morbidity in veterinary patients. This is likely because assessment of
neuropathic pain in people relies heavily on self-reporting, something our
veterinary patients are not able to do. The development of neuropathic pain
is a complex phenomenon, and concepts related to it are frequently not
addressed in the standard veterinary medical curriculum such that
veterinarians may not recognize this as a potential problem in patients. The
goals of this review are to discuss basic concepts in the pathophysiology of
neuropathic pain, provide definitions for common clinical terms used in
association with the condition, and discuss pharmacological treatment
options for dogs with neuropathic pain. The development of neuropathic pain
involves key mechanisms such as ectopic afferent nerve activity, peripheral
sensitization, central sensitization, impaired inhibitory modulation, and
pathologic activation of microglia. Treatments aimed at reducing neuropathic
pain are targeted at one or more of these mechanisms. Several drugs are
commonly used in the veterinary clinical setting to treat neuropathic pain.
These include gabapentin, pregabalin, amantadine, and amitriptyline.
Proposed mechanisms of action for each drug, and known pharmacokinetic
profiles in dogs are discussed. Strong evidence exists in the human
literature for the utility of most of these treatments, but clinical
veterinary-specific literature is currently limited. Future studies should
focus on objective methods to document neuropathic pain and monitor response
to therapy in veterinary patients."
Cranial Suture Closure in Domestic Dog Breeds and
Its Relationships to Skull Morphology
. Madeleine Geiger, Sinah
Haussman. Anatomical Rec. April 2016;299(4):412-420. Quote: "Bulldog-type
brachycephalic domestic dog breeds are characterized by a relatively short
and broad skull with a dorsally rotated rostrum (airorhynchy). Not much is
known about the association between a bulldog-type skull conformation and
peculiar patterns of suture and synchondrosis closure in domestic dogs. In
this study, we aim to explore breed-specific patterns of cranial suture and
synchondrosis closure in relation to the prebasial angle (proxy for
airorhynchy and thus bulldog-type skull conformation) in domestic dogs. For
this purpose, we coded closure of 18 sutures and synchondroses in 26 wolves,
that is, the wild ancestor of all domestic dogs, and 134 domestic dogs
comprising 11 breeds. Comparisons of the relative amount of closing and
closed sutures and synchondroses (closure scores) in adult individuals
showed that bulldog-type breeds have significantly higher closure scores
than non-bulldog-type breeds and that domestic dogs have significantly
higher closure scores than the wolf. We further found that the prebasial
angle is significantly positively correlated with the amount of closure of
the basispheno-presphenoid synchondrosis and sutures of the nose
(premaxillo-nasal and maxillo-nasal) and the palate (premaxillo-maxillary
and interpalatine). Our results show that there is a correlation between
patterns of suture and synchondrosis closure and skull shape in domestic
dogs, although the causal relationships remain elusive."
Inheritance of Chiari-Like Malformation: Can a Mixed Breeding Reduce the
Risk of Syringomyelia
. Susan P. Knowler, Henny van den Berg, Angus
McFadyen, Roberto M. La Ragione, Clare Rusbridge. PLOSone. March 2016; doi:
10.1371/journal.pone.0151280.
Quote: "Canine Chiari-like malformation (CM) is a complex abnormality of the
skull and craniocervical junction associated with miniaturization and
brachycephaly which can result in the spinal cord disease syringomyelia
(SM). ...
The heritability of SM has been estimated in the
Cavalier King Charles Spaniel (CKCS)
as moderately high (h2 = 0.37
± 0.15 standard error)  and prevalence increases with age. CM is
ubiquitous in the
CKCS
and has an estimated prevalence of
65% in Griffon Bruxellois (GB). One study investigating the breeding
programme of
CKCS
(n = 550) and GB (n = 93) found 70% and
73% respectively of offspring were free of SM if their parents were SM clear
over 5 years of age but when both parents were SM affected the risk of SM
was 92% in
CKCS
and 100% GB. ...
This
study investigated the inheritance of CM in a Griffon Bruxellois (GB) family
and feasibility of crossbreeding a brachycephalic CM affected GB with a
mesaticephalic normal Australian terrier and then backcrossing to produce
individuals free of the malformation and regain GB breed characteristics.
The study family cohort (n = 27) included five founder dogs from a previous
baseline study of 155 GB which defined CM as a global malformation of the
cranium and craniocervical junction with a shortened skull base and
increased proximity of the cervical vertebrae to the skull. T1-weighted
sagittal DICOM images of the brain and craniocervical junction were analysed
for five significant traits (two angles, three lines) identified from the
previous study and subsequent Qualitative Trait Loci analysis. Mean
measurements for mixed breed, pure-breed and baseline study groups were
compared. Results indicated that mixed breed traits posed less risk for CM
and SM and were useful to distinguish the phenotype. Moreover on the MR
images, the filial relationships displayed by the traits exhibited
segregation and those presenting the greatest risk for CM appeared additive
towards the severity of the condition. The external phenotypes revealed that
by outcrossing breed types and with careful selection of appropriate
conformation characteristics in the first generation, it is possible to
regain the GB breed standard and reduce the degree of CM. The four GB
affected with SM in the study all exhibited reduced caudal skull development
compared to their relatives. The craniocervical traits may be useful for
quantifying CM and assessing the possibility of SM thus assisting breeders
with mate selection. However, such a system requires validation to ensure
appropriateness for all breeds at risk."
Surgical stabilization of the atlanto-occipital overlap with atlanto-axial
instability in a dog
. Atsushi Fujita, Ryohei Nishimura. Japanese J.
Vet. Research. May 2016;64(2):141-145. Quote: The atlanto-occipital (AO)
overlap in combination with atlanto-axial (AA) instability was found in a
dog [Chihuahua]. We hypothesized that ventral fixation of the AA junction
can stabilize the atlas and prevent AO overlap by reviewing our past cases
with AA instability. A standard ventral fixation of the AA junction using
stainless k-wires and polymethyl methacrylate (PMMA) was performed. The dog
fully recovered, and no complication was noted. The results of the
postoperative CT imaging supported our hypothesis. The ventral fixation of
the AA junction is a feasible treatment option for similar cases, although
craniocervical junction abnormalities (CJA) including AA instability are
varied, and careful consideration is required for each case.
Does medical therapy influence the size of the syrinx in dogs with
Chiari-like malformation/syringohydromyelia comple
x?
L. Motta. j.
Small Anim. Pract. May 2016;57(5):278. Quote: "I wish to report on the effect of
medical management on progression of syringohydromyelia (SHM) in
cavalier King Charles spaniels
with Chiari-like malformation (CM).
Seven
cavalier King Charles spaniels
(age: 1 to 5 years;
mean, 2·3 years) with history, clinical signs and MRI findings suggestive of
Chiari malformation/syringohydromyelia received long-term (0·5 to 4·5 years;
mean, 2·8 years) furosemide therapy (dose: 0·8 to 2 mg/kg twice daily; mean,
1·1 mg/kg twice daily) and had repeat MRI scans between 0·5 and 4·5 years
(mean, 2·8 years) after diagnosis. Additional oral medications (gabapentin,
corticosteroids and omeprazole) were prescribed when furosemide failed to
control the clinical signs associated with CM/SHM complex. In all seven
dogs, syrinx width and length increased at the follow-up MRI and in four
cases a new syrinx had developed (Table 1). Furosemide did not prevent
further syrinx expansion nor reduce the size of the syrinx but it remains
unknown whether the medical treatment may have delayed the inevitable
expansion of the syrinx. Studies of a larger population and prospective,
randomised, blinded comparisons between different treatments (medical,
surgical, medical vs surgical) are needed to ascertain which will produce
the best clinical results."
Contents under pressure: vascular fibrous proliferation and gliosis within
the brain of
Cavalier King Charles spaniels
affected with
syringomyelia
. Clare Rusbridge, Silvia Guilluna, Daniela Menezes,
Duncan Grainger, Anna Tauro, Nicholas Jeffery, Fernando Constantinocasa,
Penny Watson, Francisco Salguero. J. Small Anim. Pract. May 2016;57(Suppl.
1):38. Quote: Chiari-like malformation (CM) is characterised by shortening
of the basicranium, reduced supraoccipital bone convexity, invagination of
the cerebellum under the occipital lobes and into the foramen magnum and
increased proximity of the atlas to the occiput. The neural tissue
overcrowding within the craniocervical junction results in obstruction of
cerebrospinal fluid pathways and failure to accommodate the arterial pulse
wave leading to variable ventriculomegaly and syringomyelia (SM). The
mechanism of SM is debated. The most accepted hypothesis is that there is a
mismatch in timing between arterial and CSF pulse peak pressure resulting in
fluid flowing into the perivascular space. However this theory is not well
supported by histopathological studies of the spinal cord in the
cavalier King Charles spaniel (CKCS)
. In this breed with a high
prevalence of CM and SM, the dominant feature is angiogenesis and fibrous
tissue proliferation in blood vessels adjacent to syrinx cavities suggesting
a response to elevated intra-cord pressure. An alternative hypothesis of SM
is that there is reduction in venous compliance resulting in increased pulse
pressure, disruption of the blood brain barrier, increased interstitial
fluid (pre-syrinx) and ultimately SM. In this retrospective cohort study we
investigate the vascular changes related to CM and SM in the cerebral
cortex. The formalin fixed brains from 26
CKCSs
(18
affected by CM and SM with ventriculomegaly and 8 without SM) were processed
for histopathological analyses. The pathological material had been obtained
from dogs humanely destroyed and donated by their owners. Tissue sections
were stained with haematoxilin and eosin, trichromic martius scarlet blue
and immunohistochemistry for glial fibrillary acidic protein. Morphometric
and digital image analyses were used to quantify the number of vessels,
width of the arteriolar wall and number of astrocytes in the cerebrum
adjacent to the lateral ventricles. SM affected animals showed a significant
increase in the number of blood vessels, associated with an increase in the
width of the arteriolar walls due to a proliferative fibrous response.
Moreover, there was a significant astrogliosis and astrocytosis in the areas
adjacent to the ependymum. The logical explanation of this
histomorphological change is a mechanical response to elevated arterial
pressure. This arterial stiffening may further affect the ability to reduce
the arterial pulse wave and decrease the CNS compliance.
Investigating canine cervical sensitivity with an electronic von Frey
aesthesiometer: a novel method of assessing syringomyelia-associated
neuropathic pain
. Heather Williams, Sandra Sanchis, Ludovic
Pelligand, Holger Volk, Joanna Murrell, Nicolas Granger. J. Small Anim.
Pract. May 2016;57(Suppl. 1):40-41. Quote: J. Small Anim. Pract. May
2016;57(Suppl. 1):40-41. Quote: Objective: To establish that the
electronic von Frey aesthesiometer (eVF) may be used to quantify cervical
skin sensitivity in
Cavalier King Charles Spaniels (CKCS)
. Background:
Cervical syringomyelia affects 70% of
CKCS
>6 years old, leading to
neuropathic pain. Neuropathic pain diagnosis is based on subjective clinical
assessment, with no objective measures currently available. The eVF allows
application of increasing pressure onto the skin via a non-invasive plastic
tip, until the dog responds (i.e. demonstrating skin sensitivity threshold).
The eVF screen displays the pressure applied in grams. Study design:
Two-centre prospective observational study, ethically covered. Methods:
CKCS
, presenting for chronic neck scratching and/or suspected neck
hypersensitivity, undergoing cervical MRI were recruited. Following
acclimatisation, the eVF, unseen by the standing dog, was applied
perpendicular to the skin by an investigator blinded to the eVF display. The
pressure obtained at the point of a behavioural response was recorded on
three consecutive times per cervical test site bilaterally, with the lowest
value used for analysis. Test sites were: (i) caudal to the atlas (C2); and
(ii) cranial to the shoulder (C4). A control reading was taken from the
dorsal aspect of the right 3rd-4th metatarsal region, with the dog in left
lateral recumbency. MRI of the caudal fossa and cervical spinal cord
followed eVF testing. Results: Data were normally distributed. Of 12
CKCS
tested, the mean (standard deviation) skin sensitivity was: (i) at C2 229.1
g (77.9) and C2 234.8 g (55.1 (right/left respectively); at C4 275.5 g
(59.5) and C4 273.5 g (91.1) (right/left respectively); and (iii) at the
metatarsus region 268.3 g (113.9). One way ANOVA did not reveal differences
between test sites (P = 0.475, F = 0.891), possibly due to the low cohort
size at this stage in the study. We will recruit 15 dogs/group/centre,
grouped by syringomyelia status (syringomyelia-free, asymptomatic,
symptomatic) before completing further analysis. Conclusion: Subjective
differences between test sites (with C4 having a higher skin sensitivity
threshold relative to C2) suggest that the eVF may be able to discriminate
differences in skin sensitivity between dogs, but these are not
statistically different with the current cohort. We propose here a novel
bedside eVF testing protocol to quantify neck pain in
CKCS
with neuropathic
pain and will report further findings based upon a larger cohort of
CKCS
with/without syringomyelia once recruitment is complete.
Scratching that itch - elucidating the spinal cord injury which causes
reflex "phantom" scratching in canine syringomyelia
. Zoe R.
Nalborczyk, Angus K. McFadyen, Jelena Jovanovik, Anna Tauro, Colin J.
Driver, Noel Fitzpatrick, Susan P. Knower, Clare Rusbridge. Chloe Cross,
Susan P. Knower, Angus K. Mcfayden, Jelena Jovanovik, Anna Tauro, Colin J
Driver, Noel Fitzpatrick, Clare Rusbridge. J. Small Anim. Pract. May
2016;57(Supp S1):60-65. Aims of study: Syringomyelia (SM)
is characterised by fluid filled cavities in the spinal cord. A classic sign
of severe SM is a tendency to scratch towards one shoulder referred to as
"phantom scratching". Stimulation of neck skin induces a rhythmic scratching
action of the ipsilateral limb. Although easy to describe, the mechanism
behind this action is less easy to elucidate. A popular explanation is that
the dogs experience alloknesis (itch evoked by lightly touching the
surrounding skin) or paraesthesia (a spontaneous or evoked sensation).
However if affected dogs experience unusual sensations why do they make
little or no skin contact? SM phantom scratching is similar to fictive
scratch which develops a few months after transection of the caudal cervical
spinal cord. In fictive scratch, stimulation of a skin receptive field
results in a reflex scratching action due to hyperactivity of the scratching
central pattern generator (CPG) i.e. neural circuits controlling a
stereotyped sequence of muscle contractions. The similarity to fictive
scratch suggests commonality of neural pathways. In this project we
investigate the neuroanatomical site that relates to phantom scratching. We
first investigate the hypothesis that phenomenon of phantom scratching is
associated with a large dorsolateral syrinx in the upper cervical spinal
cord segments. We then looked for an association to damage in other areas of
the cervical spinal cord and investigated the hypothesis that phantom
scratching is not just associated with a dorsolateral syrinx but one that
extends to the superficial dorsal horn (SDH). Methods: Medical records from
a two year period were searched for
Cavalier King Charles Spaniels
that had magnetic resonance imaging and diagnosis of clinical SM. The cohort
was divided into SM with phantom scratching (19 dogs) and SM but no phantom
scratching (18 dogs). The MRI studies were anonymised, randomised and viewed
in EFILM TM. For each transverse image the maximum perpendicular dimensions
of the syrinx in each spinal cord quadrant was determined. Visual assessment
was made as to whether the syrinx extended to the SDH. Results: The study
found that phantom scratching is associated with a large dorsolateral syrinx
that extends to the SDH in the C3-C6 spinal segments (C2-C5 vertebrae). The
study did not find an association to damage of other areas of cervical
spinal cord. Conclusion: Phantom scratching in the dog is associated with a
large syrinx that extends to the SDH in the C3-C6 spinal segments. We
propose that phantom scratching is due to damage to projection neurons in
lamina I of the SDH with consequent reduced descending inhibition to the
lumbosacral scratching CPG. Drugs affecting SDH targets may be useful for
management of phantom scratching. If a dog has SM extending to the SDH then
it is at risk for phantom scratching. If an itchy SM affected dog has no SDH
involvement then alternative explanations for scratching (e.g. allergic skin
disease) should be investigated. (See also
this November 2017 article
.)
Forebrain conformation changes in Chiari-like malformation
. Chloe
Cross, Susan P. Knower, Angus K. McFayden, Jelena Jovanovik, Anna Tauro,
Colin J. Driver, Noel Fitzpatrick, Clare Rusbridge. J. Small Anim. Pract.
May 2016;57(Suppl. 1):63-64. Quote: Aims of study: Chiari-like Malformation
(CM) is a caudal fossa and craniocervical junction disorder resulting in
cerebrospinal fluid pathway obstruction and variable syringomyelia (SM).
Recent studies suggest that conformational changes are not confined to the
hindbrain and that the entire skull base is foreshortened. Insufficient room
for the forebrain may contribute to caudal displacement and overcrowding of
the hindbrain. The olfactory bulbs (OB) are ventrally orientated in
brachycephalic dogs; it has been suggested that this may be more extreme in
CM. Recently genetic studies have suggested a candidate gene Sall-1 for
canine CM. Sall-1 deficiency in mice is associated with decreased OB size
and defects in the human orthologue can be associated with skull
abnormalities. We hypothesise
Cavalier King Charles Spaniels (CKCS)
with CM and SM have smaller and more ventrally orientated OB with rostral
forebrain flattening. We compared OB size, angulation between the OB and the
hard palate and two measurements that represent flattening of the rostral
forebrain from 5 phenotypic groups. Methods: Medical records from a 2 year
period were searched for
CKCS
that had brain magnetic
resonance imaging (MRI) and neurological assessment. The cohort was divided
as follows: SM with phantom scratching (15 dogs); clinical SM (e.g. pain)
but no phantom scratching (17 dogs); behavioural signs of pain with CM but
no SM (25 dogs);
CKCS
with no SM and no behavioural signs
of pain or scratching (13 dogs). In addition medical records were searched
for dogs in the 5-15kg weight range with normal brain MRI (19 dogs including
5 brachycephalic). The MRI studies were anonymised, randomised and viewed in
EFILM TM. 5 measurements were taken from the T2W mid-sagittal brain MRI: the
OB length and height (product represented OB size), angulation between the
dorsal OB and the frontal lobe (bottom angle), angulation between the
frontal and parietal lobes (top angle) and angulation between the OB and
hard palate (OB angle). Results: There was a trend for decreasing mean OB
size with increasing CMSM phenotype severity (SM-scratchers < SM
non-scratchers < CM-pain <
CKCS
-control control) However post hoc analysis, Bonferroni, indicated that only
"other-breed-control" was significantly different from the CMSM groups but
was not significantly different from "
CKCS
control". ANOVA
analysis for OB, bottom and top angle did not reveal a statistically
significant difference between the groups however for OB angle there was an
apparent separation between the control and CMSM groups suggesting a trend
towards more ventrally orientated OB with increasing CMSM phenotype
severity. Conclusion: This study suggests that CM should be considered a
more global brain and skull conformational disorder with features of extreme
brachycephaly including smaller more ventrally orientated OB however further
work is required and the measurement technique has been refined for future
studies. We recommend that future studies into MRI conformation of CM and SM
uses rigorous phenotyping based on clinical signs and age.
In vitro comparative evaluation and stability studies of different brands of
pregabalin (75 mg) capsules marketed in Karachi, Pakistan: A case study
Muhammad Arif Asghar, Syed Baqir Shayum Naqvi. Sci.Int.(Lahore). May
2016;28(3):3091-3096. Quote: Pregabalin is a drug of choice for the
treatment of epilepsy. Several brands are available in the market which
makes it difficult to select the safe, effective and economic one.
Therefore, the current study was designed to evaluate and compare the
quality and physicochemical characteristics of six different pharmaceutical
brands of Pregabalin (75 mg) capsules available in the pharmacies of
Karachi, Pakistan. The comparison was based on different parameters such as,
price, uniformity of dosage unit, disintegration time, dissolution
assessment, chemical assay and stability of Pregabalin using standard
methods. The result showed that almost all brands of Pregabalin are within
the limits of manufacturers claim and meet USP/BP specifications. However,
statistical calculations and similarity factor (f2) studies also revealed
that all brands are pharmaceutically equivalent in their quality aspects. On
the basis of achieved results, it was concluded that the cost-effective
brands of Pregabalin should be utilized for the treatment of epilepsy.
Longitudinal Study of the Relationship among Craniocervical Morphology,
Clinical Progression, and Syringomyelia in a Cohort of
Cavalier King
Charles Spaniels
. S. Cerda-Gonzalez, N.J. Olby, E.H.
Griffith. J. Vet. Int. Med. June 2016. Quote: Background: Craniocervical
junction (CCJ) anomalies and secondary syringomyelia are commonly diagnosed
in
Cavalier King Charles spaniel (CKCS)
. Familiarity with
the natural history of these abnormalities is vital to understanding the
disease syndrome. Objective: To evaluate magnetic resonance imaging (MRI)
predictors of worsening clinical signs, syringomyelia, and morphology in
CKCS
longitudinally. Animals: Fifty-four client-owned
CKCS
, 5-13 years old; 50% currently symptomatic. Methods:
Longitudinal observational study. We enrolled CKCS with an MRI of the CCJ
performed >3 years earlier. We used questionnaires and neurologic
examinations to grade initial and current clinical status. Dogs that could
be anesthetized were reimaged. Morphologic assessments included the presence
and severity of: Chiari-like malformations, medullary position,
atlantooccipital overlapping (AOO), dorsal atlantoaxial bands, and
syringomyelia. Cranial cavity volumes and foramen magnum height were
measured. Results: Clinical status was evaluated in 54 dogs; 36/54 were
reimaged. Mean follow-up was 71 months. Of initially asymptomatic dogs, 32%
were symptomatic at re-evaluation. Of initially symptomatic dogs, 56% had
worsened; 13% had improved with medical management. The morphology of the
CCJ at initial imaging did not predict development of either new or worsened
signs or syringomyelia by the time of re-evaluation. Conclusion:
Craniocervical junction anomalies assessed in this study did not appear
predictive of future clinical status or syringomyelia in our cohort. The
impacts of syringomyelia, AOO, and atlantoaxial bands on future clinical
status merit further study in larger groups of
CKCS
Clinical progression in our cohort of medically managed
CKCS
did not differ substantially from published reports of those treated
surgically.
Differential diagnosis of vertebral spinous
process deviations in archaeological and modern domestic dogs
. Dennis
F. Lawler, Chris Widga, David A. Rubin, Jennifer A. Reetz, Richard H. Evans,
Basil P. Tangredi, Richard M. Thomas, Terrence J. Martin, Charles Hildebolt,
Kirk Smith, Daniel Leib, Jill E. Sackman, James G. Avery, Gail K. Smith. J.
Archaeological Science: Reports. July 2016. Quote: Paleopathological study
of domestic animal remains can elucidate human-domesticate relationships,
when all reasonable differential diagnoses are considered. Deviated spinous
processes found on ancient domesticated dog vertebrae have been assumed to
result from pack burdens, although consideration of diagnostic alternatives
has been unclear. To more thoroughly assess the potential significance of
these features, we first generated an extensive differential diagnosis of
potential causes. Broad causal categories included: (i) morphological; (ii)
infectious; (iii) taphonomic; (iv) life history (in utero to death), with
numerous subcategories that sometimes overlap. We then evaluated these
possibilities through an observational and radiology study of 15 ancient
deliberate domestic dog burials (191 vertebrae) from the midwestern USA,
dating between 10,130 and 200 years ago. Archaeological specimens from the
UK were included to evaluate for geographic uniqueness of our observations.
We characterized deviations of spinous processes of cervical (n = 74),
thoracic (n = 51), lumbar (n = 60), and sacral (n = 6) vertebrae. Affected
spinous processes were found in 34% of cervical vertebrae, 63% of thoracic
vertebrae, 78% of lumbar vertebrae, and 50% of sacral vertebrae. Four types
of spinous process deviations were observed: (a) lateral leaning from the
base but not otherwise deviated; (b) lateral curving at some point above the
base; (c) bowing because of multiple curves; and (d) torsion along the
vertical axis. Computed tomography and micro-computed tomography were
essential tools for establishing differential diagnoses. Highlights:
Deviated vertebral spinous processes in dogs have been attributed
historically to use as pack animals. A differential diagnosis for deviated
spinous processes in domesticated dogs is presented. Observational and
imaging studies indicate that deviated vertebral spinous processes have
complex origins. Computed tomography and micro-computed tomography were
essential tools for establishing differential diagnoses. ... Syringomyelia
is a painful condition caused by a large, long, or asymmetrical syrinx in
the cervical spinal cord, and malformation of the caudal occipital bone
leads to cerebellar crowding and herniation of brain tissue, obstructing
normal flow of cerebrospinal fluid.
Dogs attending primary-care practice in England with clinical signs
suggestive of Chiari-like malformation / syringomyelia
Sanchis-Mora S, Pelligand L, Thomas CL, Volk HA, Abeyesinghe SM, Brodbelt
DC, Church DB, Thomson PC, McGreevy PD, O'Neill DG. Vet. Rec. October
2016;179(17).
Quote: The study population included all dogs [187,326 dogs] within the
VetCompass Programme (September 1, 2009 - April 29, 2014). ... Ninety-three
[93] symptomatic CM/SM cases met the case definition, giving a period
prevalence overall of 0.05 per cent. Of these cases, 34 dogs (36.6 per cent)
were female, 60 dogs (64.5 per cent) were neutered and 63 dogs (67.7 per
cent) were insured. The most commonly affected breed overall was the
Cavalier King Charles Spaniel (CKCS)
, accounting for 65 (69.9 per
cent) of the case dogs. ...
The period prevalence in the CKCS was 1.6 per
cent [out of a total of 4046
CKCSs
]. ... Of these overall
cases, there were 29 (44.6 per cent) females, 42 (64.6 per cent) neutered
and 44 (67.7 per cent) insured
CKCSs
. Among the cases, 34
(52.3 per cent) were Blenheim, eight (12.3 per cent) ruby, three (4.6 per
cent) black and tan and 20 (30.8 per cent) tricolour. During the study
period, 11 of the 65 symptomatic
CKCSs
were euthanased/died
(27.7 per cent). Nine of symptomatic
CKCSs
(10.8 per cent)
died directly as a result of CM/SM. ... [T]he current study failed to
identify a significant association between colour coat and symptomatic CM/SM
diagnosis. Similarly, age did not statistically affect symptomatic diagnosis
in the
CKCS
... Other breeds affected included the King Charles Spaniel
(KCS) (16 dogs, 17.2 per cent); crossbred (three dogs, 3.2 per cent);
Chihuahua and Yorkshire Terrier (two dogs each, 2.2 per cent) and the Pug,
Affenpinscher, Jack Russell terrier, Pomeranian and Shih Tzu (one dog each,
1.1 per cent). Of the three recorded crossbred CM/SM cases, two were
recorded as being partly
CKCS
. ... Insured dogs had 4.6
times the odds of having a diagnosis of CM/SM compared with uninsured dogs.
... In the 93 cases, the most common sign reported for CM/SM was pain (67
dogs, 72 per cent). The most common manifestations were phantom
scratching (36 dogs, 38.7 per cent), spontaneous yelping (27 dogs, 29 per
cent), neck pain on palpation (16 dogs, 17.2 per cent) and provoked yelping,
for example, vocalisation when picked up or touched (15 dogs, 16.1 per
cent). ... Treatment data were available for 89 of the 93 affected dogs.
Seventy-two dogs (77.4 per cent) received one or more drugs for treatment of
CM/SM, and 17 dogs (20.4 per cent) were unmedicated. Gabapentin, NSAIDs and
corticosteroids were the most commonly prescribed treatments for CM/SM
administered to 48 dogs (67 per cent), 47 dogs (65 per cent) and 23 dogs (32
per cent), respectively. Of the 17 unmedicated dogs, six were reported to
have pain and six were reported to show only scratching behaviour (35.2 per
cent each). Of the 72 medicated dogs, 64 (88.8 per cent) were reported to
show either a partial or a full response to medication, while the remaining
nine dogs (12.5 per cent) were reported to have not improved after
treatment.
Two dogs (2.1 per cent of cases) underwent surgery for CM/SM but
the outcomes of surgery were not recorded. During the study period, 23 of
the 93 case dogs overall were euthanased/died (24.8 per cent). Of the 93
case dogs, nine (9.8 per cent) died or were euthanased as a result of CM/SM.
... Multivariable analysis identified three risk factors associated with
CM/SM: breed, age and insurance. ... Dogs aged over five years had 2.7 times
the odds of diagnosis of symptomatic CM/SM compared with dogs of less than
one year of age. Insured dogs had 4.6 times the odds of CM/SM compared with
uninsured dogs. ... Analgesics were prescribed to 72 (77.4 per cent) of the
symptomatic dogs. ... Underestimation of the true prevalence: Diagnosis of
CM/SM generally requires an MRI. However, this is a major limitation in
primary-care practice. A significant proportion of dogs in this study were
excluded because a clinical diagnosis was not made despite possible signs of
CM/SM being present and because clinical signs could be confounded with
other diagnosed diseases. This is an important source of underestimation of
the true prevalence. It is also a concern as many dogs will not reach a
final diagnosis and therefore will not be appropriately treated. This leads
to a decrease in welfare of these patients. Some dogs have been diagnosed
without MRI and therefore false positives may have been included. ... The
increased diagnosis level recorded in insured animals suggests that
financial and other constraints on diagnostic procedures may have allowed
the true prevalence of CM/SM in the overall population to be underestimated.
... This study may help to inform clinicians about the clinical relevance
and the need for improved awareness of clinical signs, particularly in
high-risk breeds, to optimise the management of CM/SM in primary-care
practice.
Acupuncture as an aid to treatment of Chiari-like malformation
(CM)/syringomyelia (SM) in a
Cavalier King Charles spaniel (CKCS)
Donal Joseph O'Leary. Vet. Rec. Case Rept. September 2016;4(2). Quote:
Syringomyelia associated with Chiari-like malformation is a common inherited
condition in the
Cavalier King Charles spaniel (CKCS)
and
often leads to debilitating clinical signs. Both conventional surgical and
medical intervention in veterinary medicine tries to address the pain
associated with the condition. The most common symptoms associated with
Chiari-like malformation in human beings are neck pain and suboccipital
headaches. ... This patient exhibited signs which suggested it was also
suffering from headaches. It often presented with a frowning expression and
during these times intensely disliked being touched, rubbed or patted on the
head. Acupuncture had a definite positive effect on this patient with
reductions in all the signs including the signs of phantom scratching and
vocalisation. ... The patient exhibited signs which suggested it was suffering from
similar clinical signs and acupuncture was used successfully as an aid to
control these clinical signs along with conventional medical treatment. ...
This patient exhibited both back and neck pain and evidence that it was
suffering from headaches is also strong. It is therefore likely that
acupuncture has positive effects on these also. ... The dog has now been
coming for acupuncture for five years. The owner reports that it has a
significant positive effect on both its demeanour and on the clinical signs.
The squinting/ 'pained' expression is virtually eliminated when the dog
comes regularly (three-week interval) for acupuncture.
Clinical and Diagnostic Imaging Features of Brain Herniation in Dogs and
Cats
M.J. Lewis, N.J. Olby, P.J. Early, C.L. Mariani, K.R. Muñana, G.S.
Seiler, E.H. Griffith. J. Vet. Internal Med. September
2016;30(5):1672-1680. Quote: Background: Quantification of brain
herniation on MRI and its immediate clinical implications are poorly
described. Objectives: Define the normal position of caudal fossa
structures on brain MRIs in dogs and cats utilizing morphometry, compare
this to dogs and cats with caudal transtentorial herniation (CTH),
foramen magnum herniation (FMH) or both identified on MRI, and
investigate associations between herniation severity, clinical signs,
and 24-hour outcome. Animals: Ninety-two controls (66 dogs, 26 cats),
119 cases with herniation (88 dogs, 31 cats). Methods: Retrospective
case series. The MRI database was searched for controls with normal
brain anatomy and cases with brain herniation. Morphometry in controls
established TTX (transtentorial to rostroventral cerebellum) to quantify
CTH and FMX (caudoventral cerebellum to foramen magnum) to quantify FMH.
Measurements were compared between cases and controls. Correlations with
specific clinical variables and outcome were investigated. Results:
Measurements in medium/large control dogs versus small dog and cat
controls were significantly different (P < .001, TTX: −0.46, −0.305,
−0.3, FMX: 0.695, 0.27, 0.25, respectively). 119/1564 (7.6%) cases that
underwent brain imaging had brain herniation. TTX and FMX were
significantly different between controls and cases with CTH or FMH (P <
.001). 67/89 (75%) cases with supratentorial lesions had no signs
directly attributable to herniation. 71/119 (60%) had a normal
anesthetic recovery. TTX was significantly associated with 24-hour
survival (P < .001). Conclusions and clinical importance: Brain
herniation can be quantified on MRI. Clinical signs directly
attributable to brain herniation commonly are absent, and more severe
CTH based on TTX is associated with a worse short-term outcome.
Perfusion-weighted Magnetic Resonance Imaging of Brachycephalic Dogs with
Ventriculomegaly
. M. J. Schmidt, A. Hartmann, K. H. von Pückler, L.
Hahnsen, N. Ondreka. Vet. Rad. & Ultra. October 2016;57(6):646-669. Quote:
Introduction: It has been shown that ventriculomegaly in dogs is associated
with a loss of periventricular white matter comparable to clinical relevant
internal hydrocephalus or normal pressure hydrocephalus (NPH). The
pathophysiology of ventricular distension is unclear currently. The aim of
this study was to compare brain perfusion in dogs with and without
ventriculomegaly using perfusion-weighted magnetic resonance imaging to
clarify, as to whether abnormal perfusion might be involved in the
pathophysiology of ventriculomegaly. Materials and methods: Perfusion was
measured in 23
Cavalier King Charles spaniels
with
ventriculomegaly, 10 healthy Beagle dogs were examined as a control group.
Perfusion-weighted images were acquired using a dynamic multishot fast-field
echo-EPI in a dorsal plane. Forty acquisitions per slice were acquired.
Contrast was automatically injected using an automatic pump (0.2 mmol/kg
body weight) in 20 ml crystalloid solution with an injection rate of 5 ml/s.
Contrast was given at the 10th acquisition. Perfusion was measured using
free-hand regions of interest (ROI) in five brain regions: periventricular
white matter, caudate nucleus, parietal cortex, hippocampus, and thalamus
using the STROKETOOL software tool. Time to peak (TTP), regional cerebral
blood flow (rCBF), regional blood volume (rCBV), and mean transit time (MTT)
was measured. Intraobserver variability was measured using kappa statistics.
Differences between groups were tested using Mann-Whitney U-tests.
Significance level was <0.05. Results: rCBF and rCBV were significantly
lower in the periventricular white matter of the dogs with ventriculomegaly
compared to control dogs (P < 0.001) but not for the other ROIs. Kappa
statistics revealed substantial agreement between measurements (0.82).
Discussion: Based on the differences in periventricular perfusion
ventriculomegaly should be interpreted as a form of NPH as suggested
previously. The impaired perfusion might be the reason for the reduced white
matter volume in these dogs. This has been shown in laboratory rodents with
experimentally induced hydrocephalus and humans with NPH. Cognitive studies
should be conducted to investigate a possible impairment of memory,
learning, and spatial orientation as present in humans with NPH.
Utility of the Electronic Von Frey Aesthesiometer to Quantify Cervical Skin
Sensitivity in Dogs with Syringomyelia
. H. Williams, S. Sanchis, H.
A. Volk, L. Pelligand, J. Murrell, N. Granger. J. Vet. Int. Med. November
2016;30(6):1937. Quote: Only 35% of
Cavalier King Charles Spaniels (CKCS)
with syringomyelia display pain-associated behaviours, but we suspect that a
greater proportion experience pain. An objective means of detecting pain in
these dogs is lacking. Electronic von Frey aesthesiometer (eVF) testing
consists of applying pressure onto the skin via a plastic tip. The pressure
value is displayed electronically. Exceeding a certain pressure, defined as
the skin sensitivity threshold, triggers a behavioural response from the
dog. We conducted an ethically-approved, two-centre prospective
observational study to assess whether the eVF could differentiate, based on
cervical skin sensitivity threshold,
CKCS
with: (i)
syringomyelia and clinical signs (syringomyelia-symptomatic - SM-S); (ii)
syringomyelia without clinical signs (syringomyelia-asymptomatic - SM-A);
and (iii) no syringomyelia (syringomyelia-free - SM-F). All dogs had
cervical and caudal fossa magnetic resonance imaging. Following
acclimatisation, the eVF was applied by an investigator blinded to the eVF
display and skin sensitivity threshold recorded at C2 and C4 vertebrae
bilaterally (three measures per site) and at the right dorsal metatarsal
(RH). Data were analysed with multiple analysis of variance including fixed
factors (centre, medication, group) and covariates (RH, age, clinical signs
duration). Seventy
CKCS
were recruited into: SM-S (37),
SM-A (15), SM-F (18). No difference in sensitivity was found between groups,
except for the RH when analysed as a covariate (P = 0.031) but not post-hoc
as a dependent variable (P = 0.885). Split plot analysis of variance
demonstrated differences between cervical sites, independently of
syringomyelia group (P < 0.001). In conclusion, eVF assessment of skin
sensitivity does not differ significantly by syringomyelia status.
RETURN TO TOP
2017
Use of Morphometric Mapping to Characterise Symptomatic Chiari-Like
Malformation, Secondary Syringomyelia and Associated Brachycephaly in the
Cavalier King Charles Spaniel
. Susan P. Knowler,
Chloe Cross, Sandra Griffiths, Angus K. McFadyen, Jelena Jovanovik, Anna
Tauro, Zoha Kibar, Colin J. Driver, Roberto M. La Ragione, Clare Rusbridge.
PLOS One. January 2017. Quote: Objectives: To characterise the symptomatic
phenotype of Chiari-like malformation (CM), secondary syringomyelia (SM) and
brachycephaly in the
Cavalier King Charles Spaniel [CKCS
using morphometric [the quantitative analysis of form, a concept that
encompasses size and shape] measurements on mid-sagittal Magnetic Resonance
images (MRI) of the brain and craniocervical junction. Methods: This
retrospective study, based on a previous quantitative analysis in the
Griffon Bruxellois (GB), used 24 measurements taken on 130 T1-weighted MRI
of hindbrain and cervical region. Associated brachycephaly was estimated
using 26 measurements, including rostral forebrain flattening and olfactory
lobe rotation, on 72 T2-weighted MRI of the whole brain. Both study cohorts
were divided into three groups; Control, CM pain and SM and their
morphometries compared with each other. Results: Fourteen significant traits
were identified in the hindbrain study and nine traits in the whole brain
study, six of which were similar to the GB and suggest a common aetiology.
The
Control cohort [31
CKCS
in the hindbrain study (HBS) and 16
CKCSs
in the whole brain study (WBS)] had the most natural,
wolf-like, skull conformation in terms of ellipticity. The CM pain cohort
[28
CKCSs
in HBS and 25
CKCSs
in WBS] was
characterised by increased brachycephaly with greatest rostral forebrain
flattening, shortest basicranium and compensatory cranial height. However,
in this cohort, an increased distance between the occiput and atlas provided
fewer impediments to CSF dynamics at the foramen magnum and reduced the risk
for SM. The SM cohort [71
CKCSs
in HBS and 31
CKCSs
in WBS] exhibited two conformation anomalies. One phenotype variation was
influenced by incongruities at the craniocervical junction and increased
proximity of the dens producing a 'concertina' type flexure with medullary
elevation. The other phenotypic variation was influenced by increased
brachycephaly resulted in a 'concertina' type flexure similar to the CM pain
cohort. However, both SM variations were characterised by an apparent
reduction in caudal fossa volume which compromised the CSF dynamics in the
spinal cord. Conclusion: Morphometric mapping provides a diagnostic tool for
quantifying symptomatic CM, secondary SM and their relationship with
brachycephaly. It might identify dogs at risk of SM and CM pain to improve
diagnosis and make available a means for screening breeding dogs and provide
estimated breeding values. It is hypothesized that CM pain is associated
with increased brachycephaly and SM can result from different combinations
of abnormalities of the forebrain, caudal fossa and craniocervical junction
which compromise the neural parenchyma and impede cerebrospinal fluid flow.
Motion
picture
highlights the dynamic changes of the skull conformation and
brain parenchyma associated with progressive brachycephaly and airorhynchy,
shortening of the basicranium and supraoccipital bones and the proximity and
angulation of the atlas and dens.)
Craniometric Analysis of the Hindbrain and Craniocervical Junction of
Chihuahua, Affenpinscher and Cavalier King Charles Spaniel Dogs With and
Without Syringomyelia Secondary to Chiari-Like Malformation
Susan P. Knowler, Anna-Mariam Kiviranta, Angus K. McFadyen, Tarja S.
Jokinen, Roberto M. La Ragione, Clare Rusbridge. PLOS One. January 2017.
Quote: Objectives: To characterize and compare the phenotypic variables of
the hindbrain and craniocervical junction associated with syringomyelia (SM)
in the Chihuahua, Affenpinscher and
Cavalier King Charles Spaniel (CKCS
).
Method: Analysis of 273 T1-weighted mid-sagittal DICOM sequences of the
hindbrain and craniocervical junction from 99 Chihuahuas, 42 Affenpinschers
and 132
CKCSs
. The study compared 22 morphometric features (11 lines, eight
angles and three ratios) of dogs with and without SM using refined
techniques based on previous studies of the Griffon Bruxellois (GB) using
Discriminant Function Analysis and ANOVA with post-hoc corrections. Results:
The analysis identified 14/22 significant traits for SM in the three dog
breeds, five of which were identical to those reported for the GB and
suggest inclusion of a common aetiology. One ratio, caudal fossa height to
the length of the skull base extended to an imaginary point of alignment
between the atlas and supraoccipital bones, was common to all three breeds
(p values 0.029 to <0.001). Associated with SM were a reduced occipital
crest and two acute changes in angulation i) 'sphenoid flexure' at the
spheno-occipital synchondrosis ii) 'cervical flexure' at the foramen magnum
allied with medulla oblongata elevation. Comparing dogs with and without SM,
each breed had a unique trait: Chihuahuas had a smaller angle between the
dens, atlas and basioccipital bone (p value < 0.001); Affenpinschers had a
smaller distance from atlas to dens (p value 0.009);
CKCS
had a shorter
distance between the spheno-occipital synchondrosis and atlas (p value
0.007). ... Ten of the fourteen significant variables were found in the
CKCS
with one, line
ac [see diagram below]
, unique
to the breed. Line
ac
indicates the proximity of the
sphenooccipital synchondrosis to the atlas bone. This study confirms the
findings of others that the
CKCS
with SM have a reduced
caudal fossa size a presumed consequence of early closure of the
spheno-occipital and possibly other cranial sutures. Compared to other
breeds including the GB, the
CKCS
has considerably greater
incidence of cerebellar deformation by the supra-occipital bone and vermis
herniation. These findings and the coexistence of occipital dysplasia and
hypoplasia suggest that the
CKCS
may have additional
predisposing risk factors for SM compared to the other breeds. ... Conclusion: The selected morphometries successfully characterised
conformational changes in the brain and craniocervical junction that might
form the basis of a diagnostic tool for all breeds. The severity of SM
involved a spectrum of abnormalities, incurred by changes in both angulation
and size that could alter neural parenchyma compliance and/or impede
cerebrospinal fluid channels.
(Figure 7, below,  links what is happening
in the front and back of the skull.)
Prevalence of dorsal notch and variations in the foramen magnum shape in dogs of
different breeds and morphotypes
. Marta Kupczyńska, Norbert Czubaj,
Karolina Barszcz, Wojciech Sokołowski, Michał Czopowicz, Halina Purzyc,
Małgorzata Dzierzęcka, Wojciech Kinda, Zdzisław Kiełbowicz. Biolgia.
February 2017;72(2):230-237. Quote: The study evaluated shape of the foramen
magnum (FM) in dog with regard to its constitutional type (small, medium and
large breeds) and morphotype (brachycephalic, mesaticephalic and dolichocephalic
dogs). ... Currently, there is a discussion among researchers whether to
consider occipital dysplasia as part of the normal morphology of the occipital
bone that occurs mainly in small breeds (including ... the
Cavalier King
Charles Spaniel
) ... Nevertheless, it has to be stated here that
problems concerning so called "occipital area" are most often found in
Cavalier King Charles Spaniels
. ... We used multi-slice CT scanner to
examine occipital area of 138 purebreds dogs. Two studied groups could be
distinguished - living animals undergoing standard diagnostic CT procedure (n =
47) and macerated skulls of euthanized dogs (n = 91). Morphometric analysis was
focused on presence of dorsal notch within foramen magnum. This anatomical
feature was present in 33.3% of examined dogs. It was more often observed in
small size dogs (70%) and those of brachycephalic morphotype (94.1%). For the
first time dorsal notch was noted in breeds such as French Bulldog, Fox Terrier,
Keeshond, Standard Schnauzer, English Bulldog, Cocker Spaniel, Boxer and
Rottweiler. We distinguished four different shape of FM: oval, pentagonal,
rhomboid and circular. Most common FM shape was oval (41 dogs; 45%) whereas
circular type was least observed (5 dogs; 5.5%). The pentagonal shape was
noticed in 27 specimens (29.7%) and the rhomboid shape in 18 dogs (19.8%).
Authors conclude that dorsal notch is not pathology and should be considered a
morphological variation within the normal anatomy. Results presented in this
study should be taken into account during interpretation of the CT images of the
craniocervical junction.
Cavalier King Charles Spaniels
with Chiari-like
malformation and Syringomyelia have increased variability of spatio-temporal
gait characteristics
. Olsen E, Suiter EJ, Pfau T, McGonnell IM,
Matiasek K, Giejda A, Volk HA. BMC Vet Res. June 2017;13(1):159. Quote:
Background: Chiari-like malformation in the
Cavalier King Charles
Spaniel
is a herniation of the cerebellum and brainstem into or
through the foramen magnum. This condition predisposes to Syringomyelia;
fluid filled syrinxes within the spinal cord. The resulting pathology in
spinal cord and cerebellum create neuropathic pain and changes in gait. This
study aims to quantify the changes in gait for
Cavalier King Charles
Spaniel
with Chiari-like malformation and Syringomyelia. Methods:
We compared
Cavalier King Charles Spaniel
with Chiari-like
malformation with (n = 9) and without (n = 8) Syringomyelia to Border
Terriers (n = 8). Two video cameras and manual tracking was used to quantify
gait parameters. Results & Conclusions: We found a significant increase in
coefficient of variation for the spatio-temporal characteristics and
ipsilateral distance between paws and a wider base of support in the
thoracic limbs but not in the pelvic limbs for
Cavalier King Charles
Spaniels
compared with the border terrier.
Syringomyelie - neue Therapieoption am Horizont?
(Syringomyelia -
new therapy option on the horizon) Stefanie Kruppke. Veterinar Spiegel. June
2017;27(02): 53-55. Quote (translated from German): The patients: Two
Cavalier King Charles Spaniels
were presented with the main
symptom "nonspecific itching" (male, 8 and 4 years old) in practice. A
complete dermatological clarification including cytology and skin scraping
was carried out beforehand. In addition, parasitic therapy was performed
with a combination preparation of 400 mg imidacloprid and 100 mg moxidectin
as well as therapy with afoxolans to exclude a parasitic itching. Afterwards
magnetic resonance tomography was diagnosed with chiari-like malformations
and syringomyelia. The initiation of gabapentin therapy (10 mg / kg every 8
hours) as a possible therapy described in the corresponding literature
showed only moderate results and an unsatisfactory result. New therapy
option? Since these therapeutic approaches do not always lead to a
satisfactory result, new approaches have been sought to help these patients.
Since the itching is a neuropathically induced itching, a preparation with
the active ingredient oclacitinib was used, which in the case of allergic
dermatitis inhibits itching in the neurological range. An important element
in inflammation and itching symptoms is the enzyme Januskinase. The immune
modulator Oclacitinib [Apoquel] inhibits this enzyme and thus the
inflammatory reactions and itching in atopic dermatitis. In the two
Cavalier King Charles Spaniels
presented, a therapy with
oclacitinib was initiated in the standard dose, which is recommended for
atopic dermatitis (0.4-0.6 mg / kg 2 × daily for 14 days, then 1 × daily
administration). The use of the immunomodulator Oclacitinib as an "off-label
use" can greatly assist the animal and owner in cases of tormenting itching
and return both a piece of life quality despite a serious diagnosis. Result
and conclusion: After only 2 days the itching is clearly reduced, no
scratching behavior can be observed after 1 week and the owners report a
generally improved general condition. Both patients are taking the drug for
a year now and are clinically inconspicuous, side effects have not occurred.
This case report has yet to be proved by larger studies, so that the exact
mechanism of action can be investigated. However, this drug may eventually
serve as a promising therapy for syringomyelia after further studies. Of
course, there is no authorization for this indication so that it is
initially an "off-label use".
Pravalenz der Chiari-ahnlichen Malformation und
der Syringomyelie bei Cavalier King Charles Spanieln in der Bundesrepublik
Deutschland
Prevalence of Chiari-like malformation and syringomyelia in
Cavalier
King Charles Spaniels
in the Federal Republic of Germany
Miriam Refai, disseration. The Justus Liebig University of Giessen. May
2017. Quote:
The aim of the present study was to establish the prevalence of Chiari-like
malformation and syringomyelia within the
CKCS
breed of
Germany and to determine whether age and/or sex had a significant influence
on the prevalence of syringomyelia. A total of 339
CKCS
were available for this study and their age ranged from 2.9 month to 11.2
years. Most of the dogs were asymptomatic and only presented by their owners
request for breeding examination using magnetic resonance imaging (MRI). In
this study we also included some dogs with clinical signs and MRI, because
of a neurologic or non-neurologic disease. Consequently the analysis of the
data record is based on the diagnostic findings of asymptomatic as well as
symptomatic
CKCS
. T1- and T2-weighted magnetic resonance
images of the head and the cranial cervical spinal cord (to C5 vertebra)
were obtained from each participant. The dogs were divided into two groups,
"affected" or "non-affected", whether they suffer from Chiari-like
malformation and/or syringomyelia or not. The classification was made in
regard to presence or absence of Chiari-like malformation and/or
syringomyelia, without any subdivision or graduation of these conditions.
Pathomorphological changes consistent with Chiari-like malformation were
found in 329 of 339
CKCS
. Without consideration of the age,
there was an overall prevalence within this tested population of 97.1% of
dogs with Chiari-like malformation. 163 of 339
CKCS
had a
proved evidence of syringomyelia at the point of examination. This finding
resulted in an overall prevalence of 48.1% of
CKCS
with a
positive diagnosis of syringomyelia. The outcome of this study revealed that
the risk of developing syringomyelia increases with the age of the
CKCS
. Additionally, it was found that syringomyelia can occur as a
late onset disease. The prevalence of dogs, that showed changes consistent
with syringomyelia, was 25% within the first year of life, but in
CKCS
over six years of age the prevalence was already 63.7%. In
spite of these findings, sex did not have a significant effect on developing
syringomyelia within the participants of this study. Therefore, the
inherited genetic defect of syringomyelia does not appear to be sex-linked.
The present study confirmed that Chiari-like malformation appears to be
ubiquitous in the
CKCS
breed and that almost half of all
dogs within the
CKCS
population seems to be affected by
syringomyelia in Germany. These results support the assumption of other
authors that the likelihood of a positive scan for syringomyelia raises with
increased age of the
CKCS
Dynamic Susceptibility Contrast Perfusion Magnetic
Resonance Imaging Demonstrates Reduced Periventricular Cerebral Blood Flow
in Dogs with Ventriculomegaly
. Martin J. Schmidt, Malgorzata Kolecka, Robert
Kirberger, Antje Hartmann. Vet. Neuro. & Neurosurgery. August 2017; doi:
10.3389/fvets.2017.00137. Quote:
The nature of ventriculomegaly in dogs is still a matter of debate. Signs of
increased intraventricular pressure and atrophy of the cerebral white matter
have been found in dogs with ventriculomegaly, which would imply increased
intraventricular pressure and, therefore, a pathological condition, i.e., to
some extent. Reduced periventricular blood flow was found in people with
high elevated intraventricular pressure. The aim of this study was to
compare periventricular brain perfusion in dogs with and without
ventriculomegaly using perfusion weighted-magnetic-resonance-imaging to
clarify as to whether ventriculomegaly might be associated with an increase
in intraventricular pressure. Perfusion was measured in 32
Cavalier King
Charles spaniels (CKCS)
with ventriculomegaly, 10
CKCSs
were examined as a
control group. Cerebral blood flow (CBF) was measured using free-hand
regions of interest (ROI) in five brain regions: periventricular white
matter, caudate nucleus, parietal cortex, hippocampus, and thalamus. CBF was
significantly lower in the periventricular white matter of the dogs with
ventriculomegaly but not in the other ROIs. Reduction of
periventricular CBF might imply increase of intraventricular pressure in
ventriculomegaly. ... Cerebral blood flow can be reduced in periventricular
white matter in
CKCSs
with ventriculomegaly, which makes
some increase of intraventricular pressure likely.
Syringomyelia and Craniocervical Junction Abnormalities in Chihuahuas
A.-M. Kiviranta, C. Rusbridge, O. Laitinen-Vapaavuori, A. Hielm-Bjorkman,
A.K. Lappalainen, S.P. Knowler, T.S. Jokinen. J. Vet. Int. Med. September
2017. Background: Chiari-like malformation (CM) and syringomyelia (SM) are
widely reported in
Cavalier King Charles Spaniels
and
Griffon Bruxellois dogs. Increasing evidence indicates that CM and SM also
occur in other small and toy breed dogs, such as Chihuahuas. Objectives: To
describe the presence of SM and craniocervical junction (CCJ) abnormalities
in Chihuahuas and to evaluate the possible association of CCJ abnormalities
with SM. To describe CM/SM-related clinical signs and neurologic deficits
and to investigate the association of CM/SM-related clinical signs with
signalment, SM, or CCJ abnormalities. Animals: Fifty-three client-owned
Chihuahuas. Methods: Prospective study. Questionnaire analyses and physical
and neurologic examinations were obtained before magnetic resonance and
computed tomography imaging. Images were evaluated for the presence of SM,
CM, and atlantooccipital overlapping. Additionally, medullary kinking,
dorsal spinal cord compression, and their sum indices were calculated.
Results: Scratching was the most common CM/SM-related clinical sign and
decreased postural reaction the most common neurologic deficit in 73 and 87%
of dogs, respectively. Chiari-like malformation and SM were present in 100
and 38% of dogs, respectively. Syringomyelia was associated with the
presence of CM/SM-related clinical signs (P = 0.034), and medullary kinking
and sum indices were higher in dogs with clinical signs (P = 0.016 and P =
0.007, respectively). Conclusions and Clinical Importance: Syringomyelia and
CCJ abnormalities are prevalent in Chihuahuas. Syringomyelia was an
important factor for the presence of CM/SM-related clinical signs, but many
dogs suffered from similar clinical signs without being affected by SM,
highlighting the clinical importance of CCJ abnormalities in Chihuahuas.
Twelve years of chiari-like malformation and syringomyelia scanning in
Cavalier King Charles Spaniels
in the Netherlands: Towards
a more precise phenotype
. Wijnrocx K, Van Bruggen LWL, Eggelmeijer
W, Noorman E, Jacques A, Buys N, Janssens S, Mandigers PJJ. PLoS One.
September 2017;12(9). Quote: Chiari-like malformation (CM), syringomyelia
(SM) and middle ear effusion (also called PSOM) are three conditions that
frequently occur in
Cavalier King Charles Spaniels (CKCS)
Both CM and SM are currently screened in the Netherlands prior to breeding
and are graded according to the British Veterinary Association's Kennel Club
(BVA/KC) scheme. This study evaluated the prevalence and estimated genetic
parameter of CM, SM and middle ear effusion from 12 years of screening
results. For SM, the classical method using the BVA/KC scheme, was compared
with exact measuring of the central canal dilation. For CM, the BVA/KC
scheme was compared with a more detailed scheme. Next to this the presence
of microchip artifacts was assessed. 1249 screening of 1020 dogs were
re-evaluated. Results indicated the presence of CM in all dogs, suggesting
it has become a breed-specific characteristic. And although different grades
of CM were observed, the condition did not deteriorate over time. SM was
present in 39% of the dogs and a clear age effect was demonstrated, with SM
increasing with age. This emphasizes the importance of screening at
appropriate age, since SM can worsen with increasing age. One alternative is
to promote repeated measures. The presence of middle ear effusion in this
study was 19%-21% for dogs younger than 3 years, and 32%-38% for dogs older
than 3 years. In as much as 60%, microchip artifacts were noticed, leading
to the recommendation to place microchips in another location in breeds that
are susceptible to developing SM. Finally, this study estimated the
heritability of CM in this population, due to the lack of phenotypic
variance, to be very low at 0.02-0.03. The heritability for SM central canal
dilatation to be 0.30, compared to 0.13 for the classical BVA/KC method,
using a model including the age effect and the combined effect of veterinary
clinic and year of the evaluation. Genetic correlations were rather small,
ranging from 0.16-0.33. As a conclusion, screening for SM and CM in the
entire population should be maintained, and a selection scheme against SM
should be based on estimated breeding values for the exact measurement of
the central canal dilatation.
Questionnaire-based Analysis of Owner-reported Scratching and Pain Signs in
Cavalier King Charles Spaniels
Screened for Chiari-like
Malformation and Syringomyelia
. C.R. Sparks, S. Cerda-Gonzalez,
E.H. Griffith, B.D.X. Lascelles, N.J. Olby. J. Vet. Intern. Med. January
2018;32(1):331-339. Quote: Background: Chiari-like malformation (CM) and syringomyelia
(SM) cause a pain syndrome in
Cavalier King Charles spaniels (CKCS)
Clinical signs are not consistently apparent on neurologic examination, and
owner reporting of signs provides vital clinical history. However, owner
questionnaires for this disease are not well developed. Objectives: To
develop a tool to capture owner-reported clinical signs for use in clinical
trials and to compare owner-reported signs with the presence of pain on
neurologic examination and SM on magnetic resonance imaging (MRI). Animals:
Fifty client-owned
CKCS
. Methods: Owners completed a
questionnaire
[linked here]
and pain/scratch map
[linked here]
. Each dog underwent a neurologic examination and
craniocervical magnetic resonance imaging (MRI). Questionnaire responses
were developed into scores, area of shading for pain/scratch maps was
measured, and consistency of responses between these tools was assessed.
Owner-reported findings were compared with neurologic examination findings
and presence and severity of SM on MRI. Results: Thirty-three dogs were
symptomatic and 17 asymptomatic; 30 had SM. ...The most common presenting
sign was phantom scratching, occurring in 32 dogs, and the most common sign
of pain was crying out when being lifted, occurring in 11 dogs.
[See
Figure 1 at right.]
... Extent
of shaded areas on maps positively correlated with questionnaire scores for
pain and scratch. Owner-reported findings were not significantly associated
with presence or severity of SM or neurologic examination findings.
Owner-reported lateralization of signs was significantly associated with SM
lateralization. Conclusions: The questionnaire and maps may be useful for
clinical trials. Lack of association of owner-reported signs with SM
highlights our lack of understanding of the pathophysiology of pain in this
disease. ... The conclusion that SM causes pain in
CKC
S is
complicated by the finding that dogs with CM but no SM can show classic
signs of neuropathic pain, as illustrated by 10 dogs in our study.
Inconsistencies have been described in prior studies as well. These data
emphasize the uncertainty surrounding the role of SM in producing signs in
these dogs. Indeed, other breeds, such as Yorkshire terriers, commonly have
SM yet do not display the same signs. ... To conclude, the full range of
signs reported by owners of
CKCS
includes a variety of
manifestations of pain, with phantom scratching as the most commonly
reported sign followed by crying out when being lifted. Owner reporting of
pain and scratch frequency and severity captured by the [revised final
questionnaire, named ChiMPS-T (Chiari-like malformation pain and scratch
tool)
inked
here
] correlates with the owner-reported surface area affected by
these signs in their dogs. Neither the scores nor the surface area reported
correlated with the presence or severity of SM, highlighting uncertainty on
the source of pain in these dogs. Further validation of these tools
including responsiveness, test-retest, and discriminatory validity needs to
be assessed. The relationship among CM, SM, and pain and scratch in this
population of dogs deserves further examination.
MRI characteristics for "phantom" scratching in canine syringomyelia
Zoe R. Nalborczyk, Angus K. McFadyen, Jelena Jovanovik, Anna Tauro, Colin J.
Driver, Noel Fitzpatrick, Susan P. Knower, Clare Rusbridge. BMC Vet. Res.
November 2017. DOI 10.1186/s12917-017-1258-2. Quote: Background: A classic
sign of canine syringomyelia (SM) is scratching towards one shoulder. Using
magnetic resonance imaging (MRI) we investigate the spinal cord lesion
relating to this phenomenon which has characteristics similar to fictive
scratch secondary to spinal cord transection. Medical records were searched
for
Cavalier King Charles spaniels
with a clinical and MRI
diagnosis of symptomatic SM associated with Chiari-like malformation (CM).
The cohort was divided into SM with phantom scratching (19 dogs) and SM but
no phantom scratching (18 dogs). MRI files were anonymised, randomised and
viewed in EFILM ™. For each transverse image, the maximum perpendicular
dimensions of the syrinx in the dorsal spinal cord quadrants were
determined. Visual assessment was made as to whether the syrinx extended to
the superficial dorsal horn (SDH). Results: We showed that phantom
scratching appears associated with a large dorsolateral syrinx that extends
to the SDH in the C3-C6 spinal cord segments (corresponding to C2-C5
vertebrae). Estimated dorsal quadrant syrinx sizes based on the
perpendicular diameters were between 2.5 and 9.5 times larger in dogs with
phantom scratching, with the largest mean difference p-value being 0.009.
Conclusion: SM associated phantom scratching appears associated with MRI
findings of a large syrinx extending into the mid cervical SDH. We
hypothesise that damage in this region might influence the lumbosacral
scratching central pattern generator (CPG). If a scratching SM affected dog
does not have a large dorsolateral cervical syrinx with SDH involvement then
alternative explanations for scratching should be investigated. (See also
this May 2016 abstract
.)
Characterisation of chiari-like malformation and secondary syringomyelia in
selected toy dog breeds using magnetic resonance imaging
. Knowler,
S. P. November 2017. Doctoral thesis, Univ. of Surrey. Quote: Chiari-like
Malformation (CM) and secondary Syringomyelia (SM) is a complex,
debilitating abnormality which compromises the normal cerebrospinal fluid
movement of the central nervous system culminating in the development of
fluid-containing cavities within the spinal cord and associated with
behavioural signs of pain and neurological deficits. The prevalence of
asymptomatic CM dogs suggest that cerebellar indentation and impaction may
be normal anatomical variations and unsuitable as a definition of CM.
Magnetic Resonance Imaging (MRI) remains the definitive means of diagnosing
CM/SM and a morphometric technique of quantifying CM and SM on mid-sagittal
MRI has been successfully applied and validated in previous studies to a
cohort of Griffon Bruxellois (GB) dogs with and without CM and a mixed breed
GB family crossed with a mesaticephalic breed (Australian Terrier). Using a
refined technique which took account of recent research findings,
morphometries using a triangulation of circles, lines and angles were used
to 'map' MRIs of the whole brain and cervical region in order to quantify
the severity of the CM and SM phenotype in the
Cavalier King Charles
(CKCS)
. A further morphometric analysis was undertaken to explore
brachycephaly and miniaturization as risk factors for CM and SM by comparing
their impact in the
CKCS
, Affenpinscher and Chihuahua
breeds. The collective framework of lines and angles generated a unique
'signature' for the dog, characterised by "concertina" type flexures
demonstrating the combined nature of segregated traits towards the severity
in the phenotype. Compared to controls,
CKCS
with CM pain
are characterised by increased brachycephaly and airorhynchy, while
significant traits for SM in the three dog breeds included those reported
for the GB, suggesting a common aetiology. The characterisation of the CM
phenotype provides the possibility of a diagnostic tool for veterinarians
and means to assist breeders with mate selection to reduce symptomatic
prevalence of CM/SM.
Chiari-like malformation and syringomyelia
. Sandra Sanchis Mora,
Ludovic Pelligand. Vet. Focus. November 2017;3:29-34. Quote: Key Points: •
Chiari-like malformation and syringomyelia are two linked conditions that
cause neuropathic pain. • A high proportion of
Cavalier King Charles
Spaniels
are affected, although other (usually small) breeds can
also be susceptible. • Clinical signs of neuropathic pain are non- specific,
and confirmation of the disease is supported by magnetic resonance imaging.
• Treatment options include using a combination of different analgesics, or
surgical decompression of the caudal cranial fossa, but owners should be
aware that neuropathic pain is challenging to treat and that the main goal
is to maintain a good quality of life for the patient.
MRI-based morphometric analysis in relation to Chiari-like malformation in
brachycephalic canine breeds
. C.R. Gordon, K. Marioni-Henry, P.
Amengual, T. Liuti. Vlaams Diergeneeskundig Tijdschrift. December
2017;86:351-360. Quote: The aim of this study was to investigate potential
differences and correlations between brain and skull morphology and the
clinical signs of brachycephalic dogs with and without Chiari-like
malformation (CLM). ... The high prevalence of CLM in the
CKCS
prohibits a comparison with CLM free dogs within this breed alone. In this
study, a strictly brachycephalic study population was utilized for
morphometric comparisons between dogs with and without CLM. ... A total of
thirty dogs were included in the study, of which five were neutered males,
seven intact males, twelve neutered females and six intact females. The
breeds represented included the
CKCS
(16), French bulldog
(5), Pug (3), Chihuahua (2), Boxer (2), Staffordshire bull terrier (1) and
the Papillon (1). Twenty dogs constituted the CLM group including
CKCS
(15), Chihuahuas (2), a Papillon (1), Staffordshire bull
terrier (1) and a Pug (1). Ten dogs without evidence of CLM on MR imaging
were classified as the control group including French bulldogs (5), Boxers
(2), a Chihuahua (1), Pug (1) and a
CKCS
(1). ... Various
measurements were derived from magnetic resonance images of the brain and
craniocervical junction of thirty brachycephalic dogs in a flexed-neck
position. Each dog was assigned a clinical grade. The distance from the
planum of the foramen magnum to the pons was significantly reduced,
providing evidence of craniocephalic disproportion similar to human patients
with Chiari malformation type I. ... The reduction of the foramen magnum to
pons distance in the current study could reflect regional shortening of the
caudal fossa, or could reflect caudal displacement of the pons by, for
example, an overcrowded forebrain. The correlation between this measurement
and the degree of cerebellar herniation is interesting as it has not
previously been identified and adds further value to this parameter and its
association with CLM in dogs. ... Cerebral length relative to cranial length
was significantly increased in dogs with CLM compared with control dogs,
supporting the hypothesis that CLM is governed by a global overcrowding of
the brain, dissimilar to the human condition. Significant correlations were
identified between these measurements and the extent of cerebellar
herniation. No significant differences or correlations were identified with
clinical grade. This is the first described morphometric analysis to use a
strictly brachycephalic study population inclusive of a control group free
from CLM. ... Another study found that syringomyelia is significantly
associated with a smaller frontal sinus size (
Scrivani
et al., 2007
). The findings of the current study suggest that this
implication could be extended to the brachycephalic subgroup, and that a
simple, linear measurement could potentially be used to assess global
crowding proven by volumetric studies, which required more specialized
software. Overcrowding in the supratentorial portion of the cranium could
potentially displace the entire cerebellum and brainstem caudally against
the occipital bone contributing to the development of cerebellar herniation
and resultant alterations in CSF. By this theory, forebrain overcrowding
could be responsible for the caudal displacement of the pons, thereby
explaining the reduction in distance between the pons and the foramen magnum
as identified in this study. ... In this study, there was no significant
difference in mid cerebellar surface area relative to mid total brain
surface area between brachycephalic dogs with and without CLM.
Foramen Magnum Decompression with Duraplasty Using Lyoplant® for Caudal
Occipital Malformation Syndrome in a Dog
. Wan-Sang Park, SungHun
Kang, Jun-Su Kim, Sung-Guon Park, Hee-Sup Moon, Sang-yeon Kim, Sung-Jin
Hong, Tae-Sung Hwang, Hee-Chun Lee, Yong-Hyun Hwang, Hyun Park, Jae-Hoon
Lee. J. Vet. Clinics. December 2017;34(6):449-453. Quote: A 3-year-old
castrated male Maltese dog, weighing 4.8 kg was referred with hindlimb
ataxia and right forelimb proprioceptive deficits were shown for 20 months.
Chiari-like malformation and syringomyelia diagnosed through MRI at a local
animal hospital and Knuckling of right forelimb and reluctance to walk were
managed with steroid. The medical management was getting ineffective to
manage for the symptoms one month before referred. Physical and neurological
examinations, radiography, computed tomography, and magnetic resonance
imaging were performed and diagnoses of caudal occipital malformation
syndrome (COMS) and subsequent syringomyelia (SM) were made. Given that
pharmacological treatment was previously ineffective, surgical intervention
was recommended. Foramen magnum decompression with duraplasty using
Lyoplant® was performed. Three days post-surgery, the dog showed improved
gait and activity. After 2 months, the dog received no additional
prescription medications. At the 12-month follow-up after surgery, the dog
showed no clinical problems or recurrences, despite complete cessation of
pharmacological treatment. In present report, we applied Lyoplant® as a
dural graft has been carried out in a dog with COMS. Surgical decompression
with Lyoplant® was an effective long-term (12-month) treatment for COMS
without the need for any pharmacological treatment.
RETURN TO TOP
2018
Assessing the relative importance of health and conformation traits in the
cavalier king Charles spaniel
. Katrien Wijnrocx,
Liesbeth François, Peter Goos, Nadine Buys, Steven Janssens. Canine Genetics
& Epidemiology. January 2018. DOI 10.1186/s40575-017-0056-2. Quote:
Background: The selection of a future breeding dog is a complicated task, in
which disease characteristics and different traits have to be combined and
weighed against one another. Truncation selection, that is the exclusion of
affected animals, may be very inefficient when selecting on a large number
of traits, and may result in a reduction of the genetic diversity in a
population or breed. Selection could be facilitated by the use of a
selection index that combines multiple traits or breeding values into one
score. This however requires a consideration of their relative value
according to their economic weight, which is difficult to express in
monetary units for health traits. The use of a choice experiment to derive
non-market values might be a solution to this problem. This is a pilot study
to assess the potential use of choice experiments to ascertain the public
preference and relative importance attached to health- and conformation
traits in the selection of a
Cavalier King Charles spaniel
... Our study also indicated that the "level of inbreeding" is considered
important by breeders and owners. ... This study invited breeders and owners
to express their attitudes towards the importance of traits in the selection
of a
CKCS
by means of a choice experiment. ... The focus
was on two prevalent disorders, mitral valve disease and syringomyelia, and
on several important conformation traits such as muzzle length and eye
shape. Based on available prior information, a Bayesian D-optimal design
approach was used to develop a choice experiment and the resulting choice
sets. Results: Every participant (breeder or owner) in the choice experiment
was presented with a total of 17 choice sets, in which at most four traits
could vary to reduce the cognitive burden. ... As the number of attributes
in a choice experiment is limited to reduce the cognitive burden of the
respondents, only following attributes were considered to be of major
interest in the choice of a
CKCS
: shape of the eyes, coat
colour, muzzle length, level of inbreeding, purchase price of the dog,
syringomyelia status, eye disease status, and mitral valve disease status.
... A total of 114 respondents [Respondents were Belgian, Danish, UK and USA
breeders and owners] participated in the choice experiment and results
showed that respondents (breeders/owners) current attitudes were directed
towards health (syringomyelia and mitral valve disease), followed by eye
shape and level of inbreeding. ... The choice experiment showed that no
difference in preference between breeders or owners, they both attached most
importance to the health traits such as SM and MVD. ... Conclusions: This
approach identifies the value breeders and owners attach to certain traits
in the breeding objective. The resulting relative weights, represented as
the logworths obtained from the choice experiment, could be an alternative
to economic weights. They could be implemented as a weight when breeding
values are available, but more study on this topic will be necessary. A
challenge in this approach is to scale up the experiment with additional
traits. Moreover, for other traits, the genetic parameters and correlations
should be known first, in order to include them in the health selection
index as well.
Computer simulation of syringomyelia in dogs
. Srdjan Cirovic,
Robert Lloyd, Jelena Jovanovik, Holger A. Volk, Clare Rusbridge. BMC Vet.
Res. March 2018;14:82-91. Quote: Background: Syringomyelia is a pathological
condition in which fluid-filled cavities (syringes) form and expand in the
spinal cord. Syringomyelia is often linked with obstruction of the
craniocervical junction and a Chiari malformation, which is similar in both
humans and animals. Some brachy-cephalic toy breed dogs such as
Cavalier King Charles Spaniels (CKCS)
are particularly predisposed.
The exact mechanism of the formation of syringomyelia is undetermined and
consequently with the lack of clinical explanation, engineers and
mathematicians have resorted to computer models to identify possible
physical mechanisms that can lead to syringes. We developed a computer model
of the spinal cavity of a
CKCS
suffering from a large
syrinx. The model was excited at the cranial end to simulate the movement of
the cerebrospinal fluid (CSF) and the spinal cord due to the shift of blood
volume in the cranium related to the cardiac cycle. To simulate the normal
condition, the movement was prescribed to the CSF. To simulate the
pathological condition, the movement of CSF was blocked. Results: For normal
conditions the pressure in the SAS was approximately 400 Pa and the same
applied to all stress components in the spinal cord. The stress was
uniformly distributed along the length of the spinal cord. When the blockage
between the cranial and spinal CSF spaces forced the cord to move with the
cardiac cycle, shear and axial normal stresses in the cord increased
significantly. The sites where the elevated stress was most pronounced
coincided with the axial locations where the syringes typically form, but
they were at the perimeter rather than in the central portion of the cord.
This elevated stress originated from the bending of the cord at the
locations where its curvature was high. Conclusions: The results suggest
that it is possible that repetitive stressing of the spinal cord caused by
its exaggerated movement could be a cause for the formation of initial
syringes. Further consideration of factors such as cord tethering and the
difference in mechanical properties of white and grey matter is needed to
fully explore this possibility. (See also this
December 2015 abstract
by the same research team.)
Evidence of negative affective state in
Cavalier King Charles
Spaniels
with syringomyelia
. Alastair Cockburn, Melissa
Smith, Clare Rusbridge, Carol Fowler, Elizabeth S. Paul, Joanna C. Murrell,
Emily J. Blackwell, Rachel A. Casey, Helen R. Whay, Michael Mendl. Applied
Anim. Behaviour Sci. April 2018;201:77-84.
Quote: Syringomyelia is a common and chronic neurological disorder affecting
Cavalier King Charles Spaniels
. The condition is putatively
painful, but evaluating the affective component of chronic pain in non-human
animals is challenging. Here we employed two methods designed to assess
animal affect - the judgement bias and reward loss sensitivity tests - to
investigate whether
Cavalier King Charles Spaniels
with
syringomyelia (exhibiting a fluid filled cavity (syrinx) in the spinal cord
of >2 mm diameter) were in a more negative affective state than those
without the condition. Dogs with syringomyelia did not differ in age from
those without the condition, but owners reported that they scratched more (P
< 0.05), in line with previous findings. They also showed a more negative
judgement of ambiguous locations in the judgement bias task (P < 0.05),
indicating a more negative affective state, but did not show a greater
sensitivity to loss of food rewards. These measures were unaffected by
whether the dog was or was not receiving pain-relieving medication. Across
all subjects, dogs whose owners reported high levels of scratching showed a
positive judgement bias (P < 0.05), indicating that scratching was not
directly associated with a negative affective state. Tests of spontaneous
behaviour (latency to jump up to or down from a 30 cm high platform) and
physiology (thermography of the eye) did not detect any differences. These
results provide initial evidence from the judgement bias task that
syringomyelia may be associated with negative affect in dogs, and open the
way for further and larger studies to confirm findings and investigate the
effects of medication in more detail. • Dogs with syringomyelia (SM) show a
more negative judgement bias than those without SM. • SM dogs do not show a
greater sensitivity to reward loss than SM-free dogs. • SM dogs scratch more
than SM-free dogs but do not differ in jump up/down tests. • SM may be
associated with negative affect in
Cavalier King Charles Spaniels
Understanding and Treating Chiari-like Malformation and Syringomyelia in
Dogs
. Ashley C. Hechler, Sarah A. Moore. Topics in Compan. Anim.
Med. March 2018. doi:10.1053/j.tcam.2018.03.002 Quote: Chiari-like
malformation (CM) and syringomyelia (SM) are common and debilitating
conditions in toy and small breed dogs. CM, considered ubiquitous in the
cavalier King Charles spaniel (CKCS)
population, results in
abnormal cerebrospinal fluid dynamics which can lead to the development of
SM. The clinical signs associated with CM/SM are frequently confused with
other otologic and dermatologic conditions, which may delay appropriate
treatment. A definitive diagnosis of CM/SM requires advanced imaging;
however, due to expense associated with this, many cases are managed
presumptively and symptomatically for the condition. The primary goal of
treatment is to manage neuropathic pain and neurologic deficits through
pharmaceutical or surgical approaches. Current literature suggests that most
CM/SM-affected dogs have progression of their clinical signs in spite of
medical or surgical management; however, most maintain a good quality of
life based on owner assessments. Lack of correlation between structural
markers of disease and clinician and owner-derived measures of neuropathic
pain highlight the need for more robust, quantitative measures of pain in
this common veterinary disease. ... CM/SM is a complex condition of small
and toy breed dogs for which both medical and surgical management can be
considered. Development of objective, quantitative assessments to document
both the presence and severity of neuropathic pain are important for future
studies comparing outcomes between medical and surgical management, and for
documenting response to novel medical therapies. Clinicians should be aware
that the most common clinical sign of the condition is phantom scratching,
which can be mistaken for dermatologic and otologic conditions also common
in small breed dogs. The genesis of phantom scratching in CM/SM is unclear,
and its relevance as a surrogate marker of neuropathic pain in veterinary
clinical studies should be further scrutinized.
A genome-wide association study identifies candidate loci associated to
syringomyelia secondary to Chiari-like malformation in
Cavalier King
Charles Spaniels
. Frederic Ancot, Philippe Lemay, Susan P.
Knowler, Karen Kennedy, Sandra Griffiths, Giunio Bruto Cherubini, Jane
Sykes, Paul J. J. Mandigers, Guy A. Rouleau, Clare Rusbridge, Zoha Kiba. BMC
Genetics. March 2018;19:16. Quote: Background: Syringomyelia (SM) is a
common condition affecting brachycephalic toy breed dogs and is
characterized by the development of fluid-filled cavities within the spinal
cord. It is often concurrent with a complex developmental malformation of
the skull and craniocervical vertebrae called Chiari-like malformation (CM)
characterized by a conformational change and overcrowding of the brain and
cervical spinal cord particularly at the craniocervical junction. CM and SM
have a polygenic mode of inheritance with variable penetrance. Results: We
identified six cranial T1-weighted sagittal MRI measurements that were
associated to maximum transverse diameter of the syrinx cavity. Increased
syrinx transverse diameter has been correlated previously with increased
likelihood of behavioral signs of pain. We next conducted a whole genome
association study of these traits in 65
Cavalier King Charles
Spaniel (CKCS)
dogs (33 controls, 32 with extreme phenotypes). Two
loci on CFA22 and CFA26 were found to be significantly associated to two
traits associated with a reduced volume and altered orientation of the
caudal cranial fossa. Their reconstructed haplotypes defined two associated
regions that harbor only two genes: PCDH17 on CFA22 and ZWINT on CFA26.
PCDH17 codes for a cell adhesion molecule expressed specifically in the
brain and spinal cord. ZWINT plays a role in chromosome segregation and its
expression is increased with the onset of neuropathic pain. Targeted genomic
sequencing of these regions identified respectively 37 and 339 SNPs with
significantly associated P values. Genotyping of tagSNPs selected from these
2 candidate loci in an extended cohort of 461
CKCS
(187
unaffected, 274 SM affected) identified 2 SNPs on CFA22 that were
significantly associated to SM strengthening the candidacy of this locus in
SM development. Conclusions: We identified 2 loci on CFA22 and CFA26 that
contained only 2 genes, PCDH17 and ZWINT, significantly associated to two
traits associated with syrinx transverse diameter. The locus on CFA22 was
significantly associated to SM secondary to CM in the
CKCS
dog breed strengthening its candidacy for this disease. This study will
provide an entry point for identification of the genetic factors
predisposing to this condition and its underlying pathogenic mechanisms.
2D quantification and characterisation of the spinal cord dorsal horn
neuronal population in
Cavalier King Charles Spaniels
with
syringomyelia
. Zoë Nalborczyk, Javier Salguero, Fernando
Constantino-Casas, Penny Watson, Clare Rusbridge. BSAVA Congress 2018
Proceedings. April 2018;p. 430. Quote: Objectives: Syringomyelia is
characterised by fluid-filled lesions in the spinal cord. A classic sign of
severe syringomyelia is 'phantom scratching', the pathogenesis of which is
unclear. It has been associated with a large dorsolateral syrinx at the
level of the C3 and C4 spinal segments with damage to the superficial dorsal
horn. We compared populations of inhibitory and excitatory interneurons in
the dorsal horn of the middle cervical spinal cord segments between
'scratchers' and 'non-scratchers' to further
investigate this. Methods:
Using image analysis software and immunohistochemistry the constituents and
neuronal populations of the middle cof the middle cervical spinal cord
segmentservical spinal cord segments of the dorsal horn for four cohorts
were identified and compared. These four cohorts included dogs with
symptomatic syringomyelia and phantom scratching, dogs with symptomatic
syringomyelia, dogs with asymptomatic syringomyelia and dogs with neither
syringomyelia nor phantom scratching. Results: 'Scratchers' had
significantly larger central cavities than 'non-scratchers'. There were
significant differences in the distribution of inhibitory interneurons in
the left and right dorsal horn of the spinal cord between the four cohorts.
There were no significant differences in excitatory interneuron
distribution. Conclusions: The results suggest there are differences in the
number of inhibitory interneurons in one or more laminae of the left and
right dorsal horn between cohorts but does not identify in which lamina(e)
the differences lie. Further complex statistical analysis and methodology
alteration are required to grasp the true significance of these results in
relation to the development of phantom scratching in dogs with severe
syringomyelia.
Behavioural and clinical signs of Chiari-like malformation and syringomyelia
in
Cavalier King Charles Spaniels
. Clare
Rusbridge. BSAVA Congress 2018 Proceedings. April 2018;pp. 430-431. Quote:
Objectives: Chiari-like malformation (CM) and syringomyelia (SM) are
associated with behavioural signs of pain and scratching. However there is
poor data on which of these non-specific signs are the most useful for
indicating symptomatic disease and whether associated with CM or SM or both.
Methods: The medical records of
Cavalier King Charles Spaniels
presenting with history of behavioural signs of pain and CM with or without
SM were analysed. Dogs with other causes of pain or scratching were
excluded. Maximum transverse diameter of the syrinx or central canal
dilation (CCD) was measured and the dogs were divided into no SM (16 dogs);
CCD<2 mm (12 dogs); SM 2-3.9 mm (23 dogs): SM>4 mm (50 dogs). Results: The
most common signs in all groups was vocalisation (spontaneous, changing head
position, on rising, when lifting dog from under the sternum);
scratching/rubbing the head/ears; unwilling or difficulty jumping/doing
stairs; hyperaesthesia to palpation of the cervical, thoracic and/or lumbar
spine; decreased exercise ability; lethargy and sleep disturbance. Phantom
scratching, scoliosis, weakness and postural deficits were only seen in the
SM>4 mm group. Conclusion: This study has limitations due to its
retrospective nature but provides data for planning future clinical trials.
Results suggest CM with or without SM may present with behavioural signs of
pain particularly associated with changes in head position. Dogs may scratch
or rub their head/ears and examination may suggest spinal hyperaesthesia. SM
specific signs tend to be associated with larger syringes and likely damage
of the spinal cord.
(See also this July 2019 article.)
Network analysis of multiple brain morphometric features in dogs to isolate
key driving factors for syringomyelia
. Olivia Saunders, Tobias
Schwarz, Katia Marioni-Henry, Tom Freeman, Nina Marie Rzechorzek. BSAVA
Congress 2018 Proceedings. April 2018;p. 494. Quote: Objectives:
Syringomyelia (SM) is an extremely painful condition that commonly affects
the
Cavalier King Charles Spaniel (CKCS)
and represents one
of the most important welfare issues currently present in veterinary
neurology. Much controversy exists surrounding the development of SM;
historically, diagnosis has focused on Magnetic Resonance Imaging (MRI)
features of the spinal cord and Chiari-like malformation (CLM) at the
skull-neck junction, overlooking potentially relevant features of the brain.
This study set out to test whether any MRI-derived morphometric features of
the brain may explain the predisposition of dogs to SM. Methods: An unbiased
approach was taken using network analysis software (Miru) to evaluate
enrichment within 8,432 data points, incorporating clinical data and blinded
retrospective measurements of brain MRI features in 246 dogs, including 22
CKCSs
. ... 22 measures of general brain and ventricular
morphology, established measures of CLM, derived measures and normalization
factors. ...  Results: Key preliminary findings included a
significant correlation between brain ventricle morphometry and breed type
in terms of length of the skull.
CKCS
dogs clustered
independently based on median age at MRI, brain length-to-volume ratio,
cerebellar volume and sulcus depth. To date, this study has generated the
most comprehensive analysis of MRI-based brain morphometry in dogs,
highlighting candidate measures to explore further as putative drivers of
SM. Conclusions: Preliminary analysis has clustered brachycephalic breeds on
the basis of ventricular morphology, and a proportion of
CKCS
dogs due to a combination of factors, including ventricular morphology.
Further analysis of this data is ongoing and will focus on parameters that
isolate CKCS dogs independently of features associated generally with
brachycephaly and parameters that isolate dogs with SM irrespective of
breed.
Three-dimensional estimation of brain ventricular system volume in
brachycephalic dogs with and without Chiari-like malformation and
syringomyelia
. Clare Perrott, Augusto Coppi, E. Jovanovik, Clare Rusbridge. BSAVA
Congress 2018 Proceedings. April 2018;p. 495. Quote: Objectives: To
ascertain if dogs with Chiari-like malformation (CM) and syringomyelia (SM) are more likely to have dilation of the lateral, third and fourth ventricles
and whether these measurements could enhance CMSM screening. Methods: Case
control study that obtained quantitative volume measurements of lateral,
third (including cavum velum interpositum and quadrigeminal cistern) and
fourth (including mesencephalic aqueduct) ventricles using Cavalieri's
principle of stereology from T2-weighted sagittal brain magnetic resonance
imaging (MRI). [Fig. 1]
The sample was composed of a Chihuahua group; five with CMSM
and five normal and a mixed brachycephalic toy breed group; eight with CMSM
and eight normal breed matched.
Cavalier King Charles Spaniels
(CKCS) were not included in the cohort. Data analysis included descriptive
statistics. Two-sample T-Tests and Mood Median Tests. Results: Stereology
measurements showed no significant difference in the lateral, third or
fourth ventricle volume between Chihuahuas and mixed brachycephalic breeds
with and without CMSM. Conclusions: A novel stereology based methodology has
successfully quantified ventricular volumes and may be applicable for future
studies in diseases that affect brain and ventricular volume. Currently a
recommendation cannot be made that the Kennel Club British Veterinary
Association CMSM Health Scheme should include assessment of ventricular
size. Continued research with increased sample sizes to reduce biological
variability and inclusion of CKCS would further confirm whether assessment
of ventricular size could provide added benefit. Additional screening
methods for CMSM are required to improve the health and welfare of
predisposed breeds.
Investigation of Sensory Thresholds in
Cavalier King Charles
Spaniels
with and without Chiari-like Malformations and
Syringomyelia
. C. R. Sparks, A. Gorney, K. Williams, B. D. X.
Lascelles, N. J. Olby. Vet. Comp. Orthop. Traumatol. May 2018;31(S 01):A6
(A0016). Quote: Introduction: Ninety-two percent of
Cavalier King Charles
Spaniels (CKCS)
have a skull malformation called Chiari-like
malformation (CM). CM is frequently associated with syringomyelia (SM), an
accumulation of fluid within the spinal cord that has been linked to a
neuropathic pain syndrome. The purpose of this study was to obtain
quantitative data on thermal and mechanical thresholds in
CKCS
with and without SM. We hypothesized that
CKCS
affected
with SM will have lower sensory thresholds when compared with unaffected
dogs. Materials and Methods: Fifty-four dogs were classified as symptomatic
or not by their owners, presence of pain was noted on neurological
examination, sensory thresholds testing was performed, and SM was identified
on magnetic resonance imaging. Results: Owners reported 24/54 dogs as
painful, 33/54 had scratching signs, 40/54 were painful on examination and
34/54 had SM. There was no significant difference in sensory thresholds
between dogs with and without SM (p > 0.5). Owner-reported symptomatic dogs
had lower mechanical thresholds on the paw (median: 0.367 kg) and neck
(2.075 kg) compared with asymptomatic dogs (0.6275 kg and 2.545 kg,
respectively) (p = 0.009 and 0.007, respectively). Dogs that exhibited pain
on neurological examination had decreased latencies to heat at the thorax
(median = 17.55 seconds) compared with dogs that were not painful (22.16
seconds) (p = 0.03). Mechanical thresholds were lower on the side of the
neck that corresponded to lateralization of SM in dogs with asymmetrical
syrinxes (p = 0.015, 0.09). Discussion: This information can be leveraged to
optimize treatment protocols and objectively study efficacy of future
therapeutics in
CKCS
Mechanical Quantitative Sensory Testing in A Canine Translational Model of
Neuropathic Pain: A Pilot Investigation
. S. A. Moore, E. T.
Hostnik, L. Cole. Vet. Comp. Orthop. Traumatol. May 2018;31(S 01):A4
(A0011). Quote: Introduction: Drug development related to neuropathic pain
is inefficient, related at least in part to limited predictive value of
experimental models. The utility of pet dogs with spontaneous disease for
use as clinical translational models has recently become a focus.
Syringohydromyelia (SM) is a painful spontaneous neurological disorder
common in pet dogs of the
Cavalier King Charles Spaniel (CKCS)
breed which results in behaviours that have long been suggested by
veterinarians to represent a neuropathic pain phenotype. Materials and
Methods: Mechanical quantitative sensory testing was performed using an
electronic von Frey anesthesiometer in normal
CKCS
(n=9)
and
CKCS
with syringomyelia (SM) (n=7). We hypothesized
that dogs with SM would have significantly lower mechanical sensory
threshold (ST) than dogs without SM, consistent with hyperesthesia and a
neuropathic pain phenotype. Results: Mean sensory threshold (ST) for normal
CKCS
was 220.4 ± 42.5 g for the thoracic limbs and 175.6 ±
21.5 g for the pelvic limbs. Mean ST for SM-affected
CKCS
was 148.8 ± 21.1 g for the thoracic limbs and 129.2 ± 8.2 g for the pelvic
limbs. There was a statistically significant decrease in ST in the pelvic
limbs of SM-affected
CKCS
compared with normal (p = 0.045).
This relationship was also present in the thoracic limbs but did not achieve
statistical significance (p = 0.094). Discussion: Spontaneously occurring SM
in pet
CKCS
may represent a valuable clinical animal model
through which to study interventions aimed at improving treatment of
neuropathic pain.
Retrospective study of 16
Cavalier King Charles Spaniel
dogs diagnosed with Chiari-Like Malformation and Syringomyelia
Magnetic Resonance Imaging and Surgical Management. Catalina Cucos, Ates
Barut, Iuliana Ionaşcu, Radu Constantinescu, Constantin Vlagioiu. Bulletin
of Univ. of Ag. Scie. & Vet. Medi. Cluj-Napoca. May 2018;75(1):118-122.
Quote: Chiari-like malformation (CM) and Syringomyelia (SM) are complex
neurological disorders, that affects the brain and respectively the spinal
cord. These conditions affect certain toy breed dogs, among which the
Cavalier King Charles Spaniel
breed is overrepresented,
causing numerous clinical signs, of which the neurological pain is commonly
observed.The purpose of this research was to describe the CM/SM magnetic
resonance images, to discuss the medical management and to track the outcome
of the patients. All of the 16
Cavalier King Charles Spaniel
dogs underwent surgical treatment, consisting of cranio-cervical
decompression, combined with drug therapy. Thirteen of the 16 cases
presented good results with clinical improvement of the symptomatology,
escpecially decreasing the neuropathic pain, and increasing the quality of
life. The other 3 cases presented no improvement of the symptomatology. ...
The study was performed on 16 Cavalier King Charles dogs, with a median age
of 35 months, 10 females and 6 males. The youngest patient in the group was
14 months old and the oldest was 97 months old. ... In all of the dogs
included in this study MRI sequences of the brain, cervical and thoracic
spinal segments were performed, showing mild identation of the cerebellum in
3 cases, marked identation of the cerebellum in 9 cases, and herniation of
the cerebellum through foramen magnum in 4 cases. All the cases presented
cervical fluid-filled cavities within the spinal cord at the time of
examination, the width syrinx varied between 1.13 mm and 6.73 mm. ... All
the dogs made a quick recovery after surgery, the neuropathic pain,
spontaneous vocalization and scratching improved in all dogs after the
surgery. In the postopertively period, none of the dogs showed complete
resolution of the clinical signs.
Morphometric Analysis of Spinal Cord Termination in
Cavalier King
Charles spaniels
. Courtney Sparks. ACVIM Forum,
Abstract N-15. June 2018. Quote:
Cavalier King Charles spaniels (CKCS)
suffer from Chiari-like malformation (CM), a skull malformation that causes
crowding of the caudal fossa, and syringomyelia (SM). Affected dogs show
signs of pain and frequently show lumbosacral pain. Tethered cauda equina
has been reported in people with CM but currently there is no morphometric
data on the caudal aspect of the vertebral column and spinal cord in CKCS.
The purpose of this study was to compare the location of the conus
medullaris in
CKCS
with other size-matched breeds. We
hypothesized that the spinal cord terminates more caudally in
CKCS
A retrospective study was conducted on 90 dogs with thoracolumbar magnetic
resonance imaging (MRI). Dog breeds were grouped as
CKCS
(n=48), and brachycephalic (n=21) and non-brachycephalic (n=20) size-matched
controls. MRI identifiers were removed to blind the observer. Termination of
the spinal cord was determined from T2-weighted sagittal and axial images as
the 6th (L6), or 7th lumbar vertebra (L7), or sacrum. Breed was revealed
after Chi-squared analyses were performed. Among 48 CKCS, the spinal cord
terminated at L6 in 3, L7 in 23, and sacrum in 22 dogs compared with 8 at
L6, 27 at L7 and 5 at sacrum in 41 controls. Spinal cord termination was
significantly more caudal in
CKCS
as compared to
brachycephalic (P = 0.015) and non-brachycephalic breeds (P = 0.005). There
was no difference between size-matched controls (P = 0.157). There is a need
to investigate whether tethering of the cauda equina contributes to signs of
pain in
CKCS
. (See also this
January 2021 article
.)
Prevalence of syringomyelia in clinically unaffected
Cavalier King
Charles Spaniels
in Germany (2006-2016)
. Sabine Schulze,
Miriam Refai, Martin Deutschland, Klaus Failing, Martin Schmidt.
Tierarztliche Praxis. June 2018;46(03):157-162. Quote: Objective: The aim of
the study was to investigate the prevalence of syringomyelia in clinically
unaffected
Cavalier King Charles Spaniels (CKCS)
in
Germany. Material and methods: From 2006 to 2016 a total of 339 asymptomatic
CKCSs from all over Germany were included. Age ranged from 3 months to 11
years (mean 3.72 years ± 2.17 years). T1- and T2-weighted magnetic resonance
images of the head and cervical spine were obtained. Results: Overall, 163
out of 339 (48.1 %)
CKCSs
showed evidence of syringomyelia.
The results (odds ratio of 1.27 per year; p < 0.0001) corroborate the
findings of other studies, in which the risk of developing syringomyelia
increases with age. Conclusion and clinical relevance: In conclusion, around
half of the dogs within the German
CKCS
population are
affected by syringomyelia. The prevalence of syringomyelia of the German
CKCS
population is similar to that of the British
CKCS
population, which is subjected to breeding strategies on the
basis of magnetic resonance imaging investigations.
Morphometric analysis of brachycephalic features identified by machine
learning technique in dogs with/without syringomyelia
. S.P.
Knowler, M. Spiteri, A.K. McFadyen, F. Stringer, K. Wells, C. Rusbridge.
ACVIM Forum Abstract N-14. June 2018. Quote: The aim of the study was a
follow up morphometric analysis of features associated with
Cavalier
King Charles spaniel (CKCS)
with syringomyelia (SM) secondary to
Chairi-like malformation (CM) that had first been identified by an
innovative machine learning technique which removes human bias. Recent
studies have suggested that CM is a more complex disorder than originally
thought and affected by features associated with brachycephaly such as
olfactory bulb rotation and rostral flattening of the forebrain. T2W
sagittal DICOM anonymized images of 66
CKCS
, over 4 years
of age were obtained, comprising i) 26 dogs without SM with no or <2mm wide
central canal dilation (ccd) ii) 40 dogs with SM with syrinx width 4mm or
over. Morphometric analysis of the shape and position of the soft palate
relative to the skull base and the nature of rostral skull flattening was
obtained. In SM dogs, the distance between the rostral end of the palate and
i) sella turcica (P= 0.049) ii) foramen magnum basioccipital (P=0.030) were
significantly reduced, as was the maximum distance through the palate
centroid (P=0.015). However, the reduced distance between the brain and
frontal bone was highly significant (P <0.001). The reduction in distance
between the olfactory bulb and the sella turcica may be of interest (P =
0.054). Discriminate analysis/logistic regression revealed that rostral
skull flattening dominated any model but when removed, ratio of maximum
distance through the palate centroid to cerebral height to cerebrum height
was highly significant (P< 0.001). Conclusion: The characteristics of
CKCS
with SM include osseous insufficiency in the skull and
changes in the shape of the soft palate which were implicated by machine
learning technology.
Morphogenesis of canine Chiari malformation and secondary syringomyelia:
Disorders of cerebrospinal fluid circulation
. Susan P. Knowler,
Gabriel L. Galea, Clare Rusbridge. Front. Vet. Sci. July 2018;doi:
10.3389/fvets.2018.00171 Quote: Chiari-like Malformation (CM) and secondary
syringomyelia (SM), as well as their analogous human conditions, is a
complex developmental condition associated with pain and accompanying
welfare concerns. CM/SM is diagnosed ever more frequently, thanks in part to
the increased availability of magnetic resonance imaging in veterinary
medicine. Research over the last two decades has focused primarily on its
pathophysiology relating to overcrowding of the cranial caudal fossa. More
recent characterisations of CM/SM include brachycephaly with osseous
reduction and neural parenchymal displacement involving the entire brain and
craniocervical junction to include rostral flattening, olfactory bulb
rotation, increased height of the cranium, reduced cranial base with
spheno-occipital synchondrosis angulation, reduced supraoccipital and
interparietal crest and rostral displacement of the axis and atlas with
increased odontoid angulation. The most shared manifestation of CM is the
development of fluid-filled pockets (syrinx, syringes) in the spinal cord
that can be readily quantified. Dogs with symptomatic CM without SM have a
reduced basioccipital bone, compensatory increased cranial fossa height with
displaced parenchyma whereby the cerebellum is invaginated beneath the
occipital lobes but without compromising cerebrospinal fluid channels enough
to cause SM. Thus, broadly defined, CM might be described as any distortion
of the skull and craniocervical junction which compromises the neural
parenchyma and cerebrospinal fluid circulation causing pain and/or SM. The
aetiology of CM is multifactorial, potentially including
genetically-influenced, breed-specific abnormalities in both skeletal and
neural components. Since causation between specific morphologic changes and
SM or clinical signs is unproven, CM might be more appropriately considered
as a brachycephalic obstructive CSF channel syndrome (BOCCS) rather than a
single malformation. Understanding the normal development of the brain,
skull and craniocervical junction is fundamental to identifying deviations
which predispose to CM/SM. Here we review its anatomical, embryological,
bio-mechanical, and genetic underpinnings to update the profession's
understanding of this condition and meaningfully inform future research to
diminish its welfare impact.
Retrospective Study of 37
Cavalier King Charles Spaniel
Dogs Diagnosed with Chiari-Like Malformation and Syringomyelia
table Cătălina Anca Cucoș, Radu Constantinescu, Ateș Barut, Iuliana Ionașcu,
Constantin Vlăgioiu.
EuroBiotech
J. July 2018;2(3):161-164. Quote: Chiari-like malformation represents a
congenital anomaly that affects the bony cranial base and the hindbrain,
leading to fluid filled cavities formation in the spinal cord, condition
named Syringomyelia. This paper aims to assess the variety of the clinical
signs and to evaluate the magnetic resonance imaging findings in thirty-
seven
Cavalier King Charles Spaniel
dogs. The study was
performed over a four-year period, from 2013 to 2017, all cases underwent
neurological examination, full diagnostic work-up, including magnetic
resonance imaging scans of the brain, cervical and upper thoracic spinal
cord. Thirty-seven dogs were included in this study, 23 females and 14
males, with a mean age of 3.6±2.1years. The commonest clinical findings
encountered were neuropathic pain and vocalization, seen in all 37 cases,
followed by scratching, facial rubbing, paw licking, air licking, tail
chasing, seizures and unilateral facial paralysis. Different grades of
cerebellar herniation and cervical syrinxes were noted in all cases, other
magnetic resonance imaging findings encountered were medullary kinking,
presyrinx and ventriculomegaly. In establishing the diagnosis of the
Chiari-like malformation and Syringomyelia, the breed, clinical history and
the symptomatology are very important, but only magnetic resonance imaging
technique can provide quantitative assessment of the nervous system lesions.
(See also this
August 2018 abstract
.)
Clinical and diagnostic imaging features of Chiari-like malformation and
Syringomyelia in
Cavalier King Charles Spaniel
dogs -
retrospective study
. Catalina Anca Cucos, Radu Constantinescu, Ates
Barut, Iuliana Ionascu, Constantin Vlagioiu. J. Biotechnology. August
2018;280(Supp):s75-s76. Quote: Chiari-like malformation and Syringomyelia
are complex neurological disorders that affects the hindbrain, the bony
cranial base and spinal cord. The purpose of this study is to evaluate the
variety of the clinical signs and to discuss the magnetic resonance imaging
findings in
Cavalier King Charles Spaniel
dogs.
Thirty-seven dogs with a mean age of 3.6±2.1 years were included in this
study, 23 females and 14 males. Only dogs that underwent neurological
examination, full diagnostic work-up, including magnetic resonance imaging
scans of the brain, cervical and upper thoracic spinal cord were considered.
Neuropathic pain and vocalization were the commonest clinical findings,
encountered in all cases, followed by scratching (82%), facial rubbing
(29.7%),pawlicking (10.6%), air licking (10.6%), tail chasing (6.4%),
seizures (2.7%) and unilateral facial paralysis (2.7%). The magnetic
resonance imaging data revealed different grades of cerebellar herniation
and cervical syrinxes in all cases, medullary kinking (89.2%), presyrinx -
spinal cord edema (51.3%), ventriculomegaly (22.6%). In order to set
Chiari-like malformation and Syringomyelia diagnosis, the breed, clinical
history and symptomatology are very important, but magnetic resonance
imaging has a fundamental role in establishing the diagnosis. (See also this
July 2018 article
.)
The Effect of Electromagnetic Fields on Post-Operative Pain and Locomotor
Recovery in Dogs with Acute, Severe Thoracolumbar Intervertebral Disc
Extrusion: A Randomized Placebo-Controlled, Prospective Clinical Trial
Natalia Zidan, Joe Fenn, Emily Griffith, Peter J. Early, Chris L. Mariani,
Karen R. Muñana, Julien Guevar, Natasha J. Olby. J. Neurotrauma. August
2018;35:1726-1736. Quote: Spinal cord injury (SCI) attributed to acute
intervertebral disc extrusions (IVDEs) is common in dogs and is treated by
surgical decompression. Dogs with sensorimotor complete injuries have an
incomplete recovery. Pulsed electromagnetic fields (PEMFs) reduce
post-operative pain through anti-inflammatory effects and there is growing
evidence for neuroprotective effects. This randomized, controlled clinical
trial evaluated the effect of PEMF on post-operative pain and neurological
recovery in dogs with surgically treated sensorimotor complete SCI
attributed to acute IVDE. Sixteen dogs with surgically treated complete
thoracolumbar SCI were randomized to receive PEMF (15 min every 2 h for 2
weeks then twice-daily for 4 weeks) or placebo starting immediately after
diagnosis. The primary outcome was gait score at 2 weeks. Secondary measures
of gait, pain perception, and proprioceptive function were evaluated at 2
and 6 weeks. Plasma glial fibrillary acidic protein (GFAP) concentration was
measured as an SCI biomarker. Post-operative pain was quantified by
measuring mechanical sensory thresholds (MSTs) at control and surgical
sites. There was no significant difference in demographics or GFAP
concentration between the two groups at trial entry. There was no difference
in primary outcome or in secondary measures of gait, but proprioceptive
placing was significantly better at 6 weeks and GFAP concentrations were
significantly lower at 2 weeks in the PEMF group. MSTs were significantly
higher in the PEMF-treated group. We conclude that PEMF reduced
incision-associated pain in dogs post-surgery for IVDE and may reduce extent
of SCI and enhance proprioceptive placing. Larger clinical trials are
warranted.
Osteopetrosis associated with chiari-like malformation in a
cavalier
king charles spaniel
- radiological findings
. Ricardo
Fernandes, Chris Jordan, Joana Tabanez, Jeremy Rose, Clare Rusbridge, Colin
Driver. 31st ESVN-ECVN Symposium. September 2018. Poster Abstract P51.
Quote: Osteopetrosis is a genetically determined bone disease that develops
as a result of malfunction of osteoclastic activity leading to excessive
deposition of immature bone, thickening of cortical bone and narrowing of
the medullary cavities. An 18 month-old male
Cavalier King Charles
Spaniel
presented for evaluation of cervical hyperesthesia. Brain
and spinal MRI revealed a thickening and sclerosis (markedly hypointense
signal on T1 sequences) of the calvaria with complete absence of bone marrow
in the bones of the skull and vertebral bodies. There was severe Chiari-like
malformation with herniation of the cerebellum and medulla into the foramen
magnum. The occipital bone was markedly dysplastic and was compressing the
caudal aspect of the cerebellum. The medulla was compressed by the
cerebellum dorsally and by the dens of the axis ventrally. Spinal MRI
revealed syringomyelia within the C2-C3 and C5-L3 segments. The maximal
width of a syrinx (4.8mm) occurred at the level of T4, at which level very
little spinal cord parenchyma remained. Radiography confirmed thickening of
the cortices and narrowing of the medullary cavities of the appendicular
skeleton. Haematology confirmed a non-regenerative anaemia consistent with
myelopthisis. We hypothesise that a mass effect from the calvarial
thickening leads to reduced volume of the caudal fossa and cerebellar
herniation. The absence of osteoclastic activity may lead to abnormal growth
of the occipital bone resulting in a smaller caudal fossa. This is the first
case report where MR findings in a patient with osteopetrosis associated
with Chiari-like malformation are described in veterinary medicine.
(See
also
this March 2019 article
on the same study.)
Investigation of sensory thresholds in
Cavalier King Charles
Spaniels
with and without Chiari-like malformations and syringomyel
ia
Courtney
R. Sparks, Angela Gorney, Kim Williams, Emily H. Griffith, Sofia
Cerda-Gonzalez, B. Duncan X. Lascelles, Natasha J. Olby. J. Vet. Int. Med.
October 2018. DOI: 10.1111/jvim.15297 Quote: Background:
Cavalier
King Charles Spaniels (CKCS)
suffer pain associated with
Chiari-like malformation and syringomyelia (CMSM). People suffer from a
similar condition and describe numerous sensory abnormalities. Sensory
changes have not been quantified in affected
CKCS
Objectives: To use quantitative sensory testing (QST) to quantify thermal
and mechanical thresholds in
CKCS
and to compare QST in
dogs with and without syringomyelia (SM). Animals: Forty-four CKCS. Methods:
Prospective study. Dogs underwent neurological examinations and
craniocervical magnetic resonance imaging (MRI). Thermal testing was
performed over the humerus and thorax (n=32); mechanical testing was
performed on the paw and neck (n=44). Latencies, thresholds, and response
rates were compared with presence and severity of SM on MRI, presence of
pain reported by the owner and pain identified on examination. Results:
Thirty dogs had SM, 30 were painful on examination, 29 were owner-reported
symptomatic. Thermal and mechanical variables were not significantly
different based on presence or severity of SM. Dogs with pain on examination
had decreased mechanical thresholds on the paw (0.38 kg, SD=0.18) and neck
(2.05 kg, SD=0.74) compared to thresholds of dogs without pain on
examination on the paw (0.60 kg, SD=0.30) and neck (2.72 kg, SD=0.57;
P=.021). Conclusions and Clinical Importance: Mechanical and thermal
sensitivity does not appear to be related to the presence of SM, but
mechanical sensitivity appears to be related to the presence of pain and
clinical signs. Mechanical testing may be useful for assessing sensory
abnormalities during clinical trials. ... In summary, the purpose of our
study was to quantify sensory thresholds in a cohort of
CKCS
with and without SM. We found no correlation between sensory thresholds
(quantified by mechanical thresholds, thermal latencies and mechanical and
thermal response rates) and SM. However, the presence or absence of pain on
neurological examination did correlate with mechanical thresholds. These
tools may be useful for assessing sensory changes in a clinical trial
setting. Because of the inconsistencies between the presence and severity of
SM and QST data, the relationship between SM and clinical signs deserves
further examination.
Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and
Syringomyelia
. Clare Rusbridge, Felicity Stringer, Susan P.
Knowler. Frontiers in Vet. Sci. November 2018;doi: 10.3389/fvets.2018.00280.
Quote: Chiari-like malformation (CM) and syringomyelia (SM) is a frequent
diagnosis in predisposed brachycephalic toy breeds since increased
availability of MRI. However, the relevance of that MRI diagnosis has been
questioned as CM, defined as identification of a cerebellar herniation, is
ubiquitous in some breeds and SM can be asymptomatic. ... The diagnosis of
symptomatic CM and SM can be challenging in some breeds such as the
Cavalier King Charles spaniel (CKCS)
because CM, as defined by the
BVA/KC Health Scheme is ubiquitous, and SM is prevalent but may be
asymptomatic. ... This article reviews
the current knowledge of neuroanatomical changes in symptomatic CM and SM
and diagnostic imaging modalities used for the clinical diagnosis of CM-pain
or myelopathy related to SM. Although often compared to Chiari type I
malformation in humans, canine CM-pain and SM is more comparable to complex
craniosynostosis syndromes (i.e., premature fusion of multiple skull
sutures) characterized by a short skull (cranial) base, rostrotentorial
crowding with rostral forebrain flattening, small, and ventrally orientated
olfactory bulbs, displacement of the neural tissue to give increased height
of the cranium and further reduction of the functional caudotentorial space
with hindbrain herniation. MRI may further reveal changes suggesting raised
intracranial pressure such as loss of sulci definition in conjunction with
ventriculomegaly. In addition to these brachycephalic changes, dogs with SM
are more likely to have craniocervical junction abnormalities including
rostral displacement of the axis and atlas with increased odontoid
angulation causing craniospinal junction deformation and medulla oblongata
elevation. Symptomatic SM is diagnosed on the basis of signs of myelopathy
and presence of a large syrinx that is consistent with the
neuro-localization. The imaging protocol should establish the longitudinal
and transverse extent of the spinal cord involvement by the syrinx. Phantom
scratching and cervicotorticollis are associated with large mid-cervical
syringes that extend to the superficial dorsal horn. If the cause of CSF
channel disruption and syringomyelia is not revealed by anatomical MRI then
other imaging modalities may be appropriate with radiography or CT for any
associated vertebral abnormalities.
Craniovertebral Junction Anomalies in Small Breed Dogs with Atlantoaxial
Instability: A Multicentre Case-Control Study
. Maja A. Waschk,
Beatriz Vidondo, Ines Carrera, Angel M. Hernandez-Guerra, Pierre
Moissonnier, Ioannis N. Plessas, Martin J. Schmidt, Dietmar Schnotzinger,
Franck Forterre, Christina Precht. Vet. Comp. Orthop. Traumatol. November
2018. DOI: 10.1055/s-0038-1675797. Quote: Objective: The main purpose of
this study was to define criteria to systemically describe craniovertebral
junction (CVJ) anomalies and to report the prevalence of CVJ anomalies in
small breed dogs with and without atlantoaxial instability (AAI).
Methods: Retrospective multicentre matched case-control study evaluating
magnetic resonance imaging and computed tomographic images of small breed
dogs with and without AAI for the presence of CVJ anomalies. Results: One
hundred and twenty-two dogs were enrolled (61 with [including 3 cavalier
King Charles spaniels] and 61 without AAI). Only dogs with AAI had dens axis
anomalies such as separation (n = 20) or a short-rounded conformation
(n = 35). Patients with AAI were more likely to have atlantooccipital
overlapping based on transection of McRae's line by the dorsal arch of the
atlas (odds ratio [OR] = 5.62, p < 0.01), a transection of Wackenheim's
clivus line (OR = 41.62, p < 0.01) and rostral indentation of the occipital
bone (OR = 2.79, p < 0.05). Patients with AAI were less likely to have a
larger clivus canal angle (OR = 0.94, p < 0.01) and larger occipital bone
lengths (OR = 0.89, p < 0.05). Clinical Significance: Small breed dogs with
AAI are more likely to have other CVJ anomalies such as atlantooccipital
overlapping or dens anomalies. The grade of brachycephaly does not differ
between patients with and without AAI. Certain objective criteria from human
literature were found useful for the assessment of both AAI and
atlantooccipital overlapping such as McRae's line, Wackenheim's clivus line,
and clivus canal angle. The classification criteria used can help to
evaluate CVJ anomalies in a more systematic way.
Computed tomographic finding in Chiari like malformation in
Cavalier
King Charles Spaniel
- case report
. Purdoiu, R. C.,
Ondreka, N., Kiss, T., Popovici, C., Papuc, I., Danciu, C. G., Lazar, A. C.,
Lacatus, R. Universitatea de Stiinte Agricole a Banatului Timisoara,
Medicina Veterinara. December 2018;51(2):106-111. Quote: The patient was a
female
Cavalier King Charles Spaniel
, 21-month-old, that
was initially diagnosed with otitis media, the symptoms debuted 10 months
prior the CT scanning. The symptoms consist in discomfort at the level of
the right ear, sratching and pain, the symptoms are not permanent, also the
patient avoids long walking. Behavioral changes and the symptoms are more
evident when the air pressure changes. A treatment for otitis media was
administered, but the symptoms persists. Prednisone, antibiotics,
antimitotic and clotrimazol drops was the therapy of choice. Otoscope
examination show a narrowed additive canal. ... The CT [computed tomography]
shows a typical brachycephalic head conformation with shortened facial bones
and dome shaped calvarium. The supraoccipital bone is short and stunted, the
foramen magnum appears enlarged. Part of the cerebellar vermis appears to
protrude caudally beyond the bony margin of the supraoccipital bone. Marked
but incidental deviation of the nasal septum is noted. ... A linear
hypoattenuating area is seen centrally within the cervical spinal cord level
with C2 and compatible with syringomyelia. Mild asymmetric dilation of the
lateral ventricles of the brain is noted accentuating the right side. ...
Changes of the occipital bone produce also occipital hypoplasia with
incomplete formation of the bone (Fig. 6). ... In absence of MRI
examination, the CT examination represent an alternative in diagnosing this
pathology.
RETURN TO TOP
2019
Pilot study of head conformation changes over time in the
Cavalier King
Charles spaniel
breed
. Susan Penelope Knowler, Lena Gillstedt,
Thomas J Mitchell, Jelena Jovanovik, Holger Andreas Volk, Clare Rusbridge.
Vet. Rec. January 2019;doi: 10.1136/vr.105135. Quote: Modern interpretation
of head conformation in the
Cavalier King Charles spaniel (CKCS)
has
favoured a smaller, more exaggerated, brachycephalic type than originally
described in the 1929 breed standard. Recent research studies identified
brachycephaly and reduced hind cranium as two conformational (dysmorphic)
features that increase risk for symptomatic Chiari-like malformation and
secondary syringomyelia (SM). A prospective pilot study investigated the
hypothesis that dysmorphic head features could be assessed visually and
correlated with risk of SM. ... This study aimed to find out if it is
possible to identify risk of CM/SM in a dog's head shape through evaluation
with the eye alone by breed experts. ... Hypothesis: Head conformation
(dysmorphic features) is correlated with risk of SM and can be evaluated
with the eye alone by breed experts. ...  Thirteen
CKCS
, selected from anonymised
photographic evidence, were physically appraised by authorised Kennel Club
judges using
a head shape checklist
. These subjective evaluations were then
matched with objective measurements of the cranium (cephalic index and
rostrocaudal doming) and their subsequent MRI. A positive correlation
(P=0.039) between the judges' checklist score and rostrocaudal doming
(hindskull ratio) and a positive correlation between the cephalic index and
hindskull ratio (P=0.042) were identified. Five
CKCS
had no SM and their
status tallied with 62 per cent of the judges' evaluation. Although the
ability of adjudicators to identify differences in head conformation varied,
there was sufficient association between the dysmorphic parameters and the
risk of SM to cause concern and propose a larger study in
CKCS
breed.
... This prospective investigation demonstrated that it was possible to
compare subjective evaluation of head conformation with objective
measurements and revealed a significant correlation between the subjective
visual evaluation of head conformation and an objective evaluation of
dorsoventral doming using photographs. However, this pilot investigation
demonstrated that individual adjudicators can vary in their interpretation
of the
CKCS
breed type and also suggests that measuring the
cephalic index or rostrocaudal doming alone is not a reliable indicator of
brachycephaly but should be taken together with a visual evaluation and take
account of other features, such as those on the checklist and the size of
the dog.
Mechanical sensory threshold in
Cavalier King Charles spaniels
with syringomyelia-associated scratching and control dogs
M.S.Thoefner, U.Westrup, N.Toft, O.J.Bjerrum, M.Berendt. Vet. J. February
2019; doi: 10.1016/j.tvjl.2019.01.011 Quote: Highlights: •
Cavalier
King Charles spaniels
with syringomyelia are assumed to experience
central neuropathic pain. • In humans with central neuropathic pain,
monofilaments were used to evaluate somatosensory function. • The cervical
mechanical sensory threshold was quantified with monofilaments in case and
control dogs. • Mean mechanical sensory threshold was not significantly
different between case and control dogs. • The complete somatosensory
profile needs to be characterised in order to assess whether syringomyelia
alters sensory thresholds. It is assumed that
Cavalier King Charles
spaniels
with Chiari-like malformation and syringomyelia experience
central neuropathic pain. An association between spinal cord parenchymal
lesions and specific clinical signs (e.g. spontaneous and evoked scratching,
withdrawal, and paroxysmal pain manifestations with vocalisation) has been
suggested. This led to the hypothesis that mechanical sensory threshold is
altered in clinical cases. The aim of this study was to quantify the
cervical mechanical sensory threshold using Semmes-Weinstein monofilaments
in nine
Cavalier King Charles spaniels
with Chiari-like
malformation and assumed syringomyelia-associated central neuropathic pain
compared to eight control dogs. Clinical and neurological examination
including magnetic resonance imaging was undertaken. Mean mechanical sensory
threshold was not significantly different between case and control dogs
(t-test on log10 transformed data; P = 0.25). Substantial variation within
and between dogs was seen, with individual thresholds ranging from 0.04 to
26 g in case dogs and from 0.02 to 10 g in control dogs. Based on these
results, it is unlikely that
Cavalier King Charles spaniels
with Chiari-like malformation and syringomyelia have increased mechanical
sensation characterised by lower mechanical sensory threshold when
quantified with Semmes-Weinstein monofilaments. Whether clinical cases
experience central neuropathic pain remains unknown. The assessment of
sensory function in dogs with assumed central neuropathic pain should be
multimodal and include not only mechanical but also tactile and thermal
threshold quantification. The use of threshold quantification in a clinical
setting is challenging due to an insufficient signal relative to the
biological background noise within and between dogs.
Morphometric analysis of spinal cord termination in
Cavalier
King Charles Spaniels
Courtney R. Sparks, Ian Robertson,
Natasha J. Olby. J. Vet. Intern. Med. February 2019; DOI:
10.1111/jvim.15437. Quote: Background: There is an association between
Chiari malformations, syringomyelia (CMSM) and tethered cord syndrome (TCS)
in people, suggesting
Cavalier King Charles Spaniels (CKCS)
with CMSM could also have TCS. Currently there are no data on the position
of the caudal spinal cord structures in
CKCS
. Objective: To
describe and compare location of spinal cord termination in
CKCS
with weightmatched controls and to examine the relationship between SM and
spinal cord termination. Animals: Thirty-nine
CKCS
and 33
controls with thoracolumbar [TL] MRIs; 34 of 39
CKCS
also had
cervical MRIs. Methods: Blinded retrospective study. Spinal cord and dural
sac termination were determined from T2-weighted sagittal and transverse
images and half-Fourier acquisition single-shot turbo spin echo sequences.
Intra-observer reliability was determined using kappa analysis. Presence of
SM was compared with location of spinal cord and dural sac termination.
Results: Intra-observer reliability was moderate for identifying spinal cord
termination (Kappa = 0.6) and good for dural sac termination (Kappa = 0.8).
The spinal cord terminated at lumbar vertebra 6 (L6) in 1, 7 (L7) in 22, and
sacrum in 16
CKCS
versus 9 at L6, 23 at L7, 1 at sacrum in
controls. Spinal cord (P < .001) and dural sac (P = .002) termination were
significantly more caudal in
CKCS
compared to controls. The
presence of thoracolumbar SM was associated with more caudal dural sac
termination in
CKCS
(P = .03). Conclusions and Clinical
Importance: ... To conclude, we found that
CKCS
have a
caudally displaced spinal cord and dural sac when compared with a range of
weight-matched breeds. These findings suggest that
CKCS
could be predisposed to TCS and that spinal cord tethering could be involved
in the development of TL SM. Future work is needed to determine whether
there is spinal cord tethering in
CKCS
, potentially through
dynamic studies, by consideration of the clinical signs and exploratory
surgery
[See, also this June 2018 abstract.]
Syringosubarachnoid shunt placement in a
cavalier king charles
spaniel dog
diagnosed with chiari like malformation and
syringomyelia
. Case report. Cătălina Anca Cucoş, Ateş Barut,
Iuliana Ionaşcu, Radu Constantinescu, Constantin Vlăgioiu. Sci. Works.
Series C. Vet. Med. 2018;LXIV(2):29-34. Quote: The aim of this paper was to
describe the syringosubarachnoid shunting as surgical management in Chiari
like malformation and Syringomyelia, and to track the outcome of the
patient. A 4-year-old
Cavalier King Charles Spaniel
female
dog was referred for neurological evaluation due to the intense sudden
attacks of pain, occurring more and more often lately. A year earlier, the
dog was diagnosed with Chiari-like malformation and syringomyelia,
undergoing to a craniocervical decompression with durotomy. Postoperatively
the clinical signs improved only for a short period of time, afterwards the
clinical symptoms progressively reappeared [progressive neuropathic pain,
expressed by sudden yelping, neck and spinal discomfort, scoliosis, apathy
and depression. Besides these clinical signs, the patient also presented
"phantom" scratching and "bunny-hopping" pelvic limb gait], worsening in the
last two months, thus requiring another surgical intervention. The dog was
subjected to surgical placement of a syringosubarachnoid shunt at the
cervical spinal cord [The maximum syrinx width is located cervical, marking
the position where the shunt will be surgically placed. ... The
syringosubarachnoid shunt was placed at the level of C3-C4. ... A
ventriculoperitoneal catheter was used to create the syringosubarachnoid
shunt.], the patient being evaluated periodically during the
hospitalization, and after that at one, four and twelve months
postoperatively. In the follow-up period the patient presented good results
with improvement of the clinical signs. ... At three years after the
syringosubarachnoid shunt placement the patient presents an amelioration of
the clinical signs comparative to the preoperative period, notably decreased
neuropathic pain, the intensity and the frequency of the pain attacks
reduced, scratching and yelping diminished, overall increasing the life
quality of the patient. ... Syringosubarachnoid shunt placement represents a
safe and efficient procedure, which leads to clinical improvement of the
clinical signs and reestablishes the quality of life. Syringosubarachnoid
shunting can be an alternative option with good results, especially in cases
in which foramen magnum decompression has failed.
Magnetic resonance findings in a
Cavalier King Charles spaniel
with osteopetrosis, Chiari-like malformation and syringomyelia
Ricardo Fernandes, C.J. Jordan, Colin Driver. Vet. Rec. Case Repts. March
2019; doi: 10.1136/vetreccr-2019-000812. Quote: Osteopetrosis (OP) is a rare
genetic condition characterised by osteoclast impairment, deficient bone
remodelling and increased bone density. Human patients with OP often present
with fractures, osteomyelitis, anaemia, abnormal skeletal development,
cranial nerve compression and rarely increased intracranial pressure
secondary to craniosynostosis and/or calvarial [skull cap] thickening. A
17-month-old male neutered
Cavalier King Charles spaniel
was presented for evaluation of occasional painful vocalisation. MR of the
brain and the vertebral column revealed a rare association of Chiari-like
malformation (CLM) and calvarial [skull cap] thickening due to diffuse OP
resulting in severe cerebellar compression and herniation into the foramen
magnum. ... MR scanning of the brain revealed partial herniation of the
cerebellar vermis into the foramen magnum, consistent with Chiari-like
malformation (CLM) and several other common associated features such as
dilatation of the lateral ventricles and
flattening
of the forebrain. There was moderate dilation of the fourth ventricle. The
occipital bone was markedly dysplastic and was compressing the caudal and
dorsal cerebellum. The skull base appeared abnormally shortened;
particularly in the region of the basioccipital bone. The spinal cord was
dorsally compressed by the cerebellum and appeared to be 'kinked' due to
ventral compression from the dens of the axis (figure 1A). There was a
marked generalised calvarial thickening that was more noticeable on
T1-weighted sequences (figure 1B,C). The bones of the skull and the
vertebral bodies demonstrated a reduction of marrow space (figure 1D,E); all
bones of the axial skeleton had markedly thickened cortices and markedly
reduced medullary canals. On MR sequences of the cervical and thoracolumbar
spine, there was diffuse syringomyelia (SM) with syringes extending from C2
to L4 (figure 2A, B). The syrinx was expanding dorsally and laterally
towards the dorsal horns of the grey matter at the level of T4, where the
syrinx reached its maximum width (4.8 mm). Orthogonal radiographs (Cuattro
DR, USA) of the appendicular skeleton revealed markedly thickened cortices
and a significant reduction of the volume of the medullary cavities of the
long bones (figure 3A, B). ... Surgical treatment (foramen magnum
decompression and dorsal laminectomy of C1) was declined by the pet owner.
Gabapentin was prescribed for control of neuropathic pain (Gabapentin;
Sandoz, 10 mg/kg every eight hours); and cimetidine (Zitac; Intervet, 10
mg/kg every 12 hours) due to its effects on histamine 2 receptors,
inhibiting cerebrospinal fluid (CSF) production. The patient demonstrated a
good clinical response to the prescribed therapy. The packed cell volume
remained reduced but stable until the patient was lost to follow-up 10
months after the initial presentation. ... To the authors' knowledge, this
report represents the first described case of calvarial thickening caused by
OP in association with CLM and syringomyelia in veterinary medicine.
(See also
this September 2018 abstract
on the same study.)
Clinical usage of gabapentin in dogs under primary veterinary care in the UK
Lavinia F Mitton, Sandra Sanchis-Mora, Ludovic Pelligand, Holger Volk, David
C Brodbelt, Dan G O'Neill. BSAVA Cong. April 2019; p. 478. Quote:
Objectives: This retrospective study aimed to explore gabapentin use in dogs
in the UK. We aimed to report usage prevalence, conditions treated,
therapeutic effectiveness, treatment duration and dose regimens, suspected
adverse reactions and accompanying treatments. Methods: The study included
318,922 dogs within the VetCompass™ Program under primary veterinary care in
2016. Data were collected from anonymised electronic medical records.
Results: Usage prevalence of gabapentin was 0.44% (95% CI: 0.42-0.47%; n =
1415). Twenty condition types were treated including: spinal pain and/or
lesion (31.7%), pain - musculoskeletal (23.9%), osteoarthritis (13.2%),
Chiarilike malformation/syringomyelia (4.7%), intervertebral disc disease
(4.3%), unspecified neuromuscular signs (4.0%), unspecified pain (3.8%),
cruciate disease (2.7%) and seizure(s) (1.9%). Gabapentin was reported to
improve clinical signs in 47.3% of dogs. The course duration was generally
short term (59.7%; <30 days between first and last dispense) and 59.6% of
doses were given twice daily. The prevalence of suspected adverse reactions
was 7.85% (95% CI: 6.57%-9.36%; n = 1438) and the most common were sedation
(5.2%) and ataxia (1.3%). The most common accompanying treatments alongside
gabapentin were non-steroidal anti-inflammatory drugs (27.2%), tramadol
(9.0%), glucocorticoids (5.6%) and opioids (4.8%). Statement (Conclusions):
This study provides useful benchmarking data on gabapentin usage in
primary-care practice and suggests a low occurrence of mild side effects.
Despite the subjective nature of the efficacy assessment, gabapentin showed
a good therapeutic efficacy. These results can assist practicing clinicians
to benchmark their clinical use of gabapentin and to predict suspected
adverse reactions.
Rostral skull changes in
Cavalier King Charles spaniels
with Chiari-like malformation and syringomyelia
. Eleonore Dumas,
Susan Penny Knowler, Felicity Stringer, Clare Rusbridge. BSAVA Congress 2019
proceeding. April 2019; p. 539. Quote: Objectives: Chiari-like malformation (CM) and
secondary syringomyelia (SM) have proven associations to multiple
morphological traits of the caudal cranium and cervical spine in
Cavalier King Charles Spaniels (CKCS)
. Since brachycephaly
increases risk for disease, this study focused on the morphology of the
rostral skull and forebrain and aimed to identify physical features
associated to development of CM associated pain (CM-P) and SM with a more
severe phenotype. Methods: Analysis of 12 measurements (11 lines and 1
angle) taken on T2 weighted midsagittal MRI of the skull and cervical spinal
cord of 66
CKCS
enabled the comparison of 3 phenotypic
groups: dogs without SM or CM-P (control group; n = 11), dogs with CM-P only
(n = 15), dogs with clinically severe CM/SM (syrinx transverse diameter >4mm
and clinical signs relating to SM; n = 40). Results: SM-affected
CKCS
had an
increased height of the cranium (p = 0.028) and reduced depth of the stop (p
= 0.006) compared to controls. SM-affected
CKCS
also had a
significant reduction in height of the nasal cavity compared to CM-P (p =
0.014). There were 2 additional significant traits comparing dogs with and
without SM; SM affected dogs had a more ventral orientation of the olfactory
bulbs (p = 0.014) and shorter distance between basicranium and hard palate
(p = 0.031). Statement (Conclusions): Dogs with symptomatic CM/SM are more
likely to have brachycephalic features of the rostral skull with "midface"
hypoplasia similar to craniosyostosis Crouzan syndrome. This not only
enhances our understanding of the disease and "at risk" head conformation
but could also impact assessment of MRI and disease diagnosis.
Prevalence of neurological disorders in
Cavalier King Charles
Spaniels
in neurology referral populations
. Katie Brown,
Rowena Packer, Holger Volk, Clare Rusbridge. BSAVA Congress 2019
proceedings. April 2019; pp. 538-9. Quote: Objectives: This study aimed to determine the
distribution of clinical presentations and the prevalence of neurological
conditions in
Cavalier King Charles Spaniels (CKCS)
. A
particular focus was placed upon establishing if syringomyelia was a
prevalent disease in
CKCS
and a frequent diagnosis in referral populations.
Methods: Records of 500
CKCS
presenting to Fitzpatrick
Referrals and the Royal Veterinary College neurology departments over a
selected four-year period (September 2013- September 2017) were searched.
Data was examined to determine the presenting clinical signs and final
diagnosis made and analysis was carried out to establish the prevalence and
frequency of these. Results: The most common clinical presentations of all
neurological conditions were behavioural signs of pain (312 cases; 62.4%),
spinal pain (238; 47.6%), phantom scratching (121; 24.2%) and gait
abnormalities (90; 18.0%). The most common final diagnosis was syringomyelia
(216 affected; 43.2% prevalence), orthopaedic conditions (74; 14.8%) and
intervertebral disc disease (60; 12.0%). Other less frequently documented
conditions included Chiari-like malformation associated pain (56; 11.2%),
myoclonus (19; 3.8%), epilepsy (18;3.6% and skin disease (12; 2.4%).
Statement (Conclusions): This study provides vital information for
veterinarians, breeders and owners of
CKCS
about common presentations of
syringomyelia and other neurological diseases to allow for earlier
recognition of these potentially painful disorders. It concludes that
syringomyelia is the most prevalent neurological disease in referral
practices and emphasizes the frequency of pain associated with neurological
disorders, but when compared to previous studies, it may be underdiagnosed
in first opinion practices.
Is CT an alternative to MRI in a morphometric analysis system for prediction
of Chiari-like malformation associated pain and syringomyelia?
Clare Rusbridge, Angus McFadyen, Felicity Stringer, Susan Knowler. BSAVA
Congress 2019 proceedings. April 2019; pp. 503-4. Quote: Objectives: A system of MRI
morphometric analysis to predict Chiarilike malformation associated pain
(CM-P) and syringomyelia (SM) has been developed. The analysis relies on
bony landmarks and computer tomography (CT) of the skull and cervical
vertebrae may be useful to predict disease risk i.e. as a more economical
pre-breeding screening test. Methods: This proof of principle pilot study
compared morphometric analysis between MRI and CT. Medical records over 4
years were searched for dog breeds predisposed to CM-P and SM that had both
MRI and CT head imaging. 13 dogs were identified (5 Chihuahua, 7
Cavalier King Charles Spaniels
, 1 Griffon Bruxellois). 13
measurements (1 circle, 1 ellipse, 7 lines, 4 angles) were taken on
midsagittal T2 weighted MRI and CT images of the skull and cervical spinal
cord. Results: ICC Model (2,1) absolute agreement showed very good agreement
for 9 measurements (ICC range 0.790-0.987); 3 measurements had some
agreement (ICC range 0.585- 0.687) and 1 angle had poor agreement (0.288).
Measurements that used bony landmarks had better agreement. Statement
(Conclusions): Morphometric analysis to predict risk of CM-P and SM can be
applied to CT but refinement will be necessary. This may eventually be
useful as a pre-breeding screening test especially if anatomical analysis
software is developed. CT is not sensitive for SM and for the foreseeable
future any hypothetical CT pre-breeding test for skeletally mature dogs
would be combined with MRI from 5 years of age to determine the final
CM-P/SM status. All data would be used in an estimated breeding value
programme.
Pregabalin for the treatment of syringomyelia-associated neuropathic pain in
dogs: A randomised, placebo-controlled, double-masked clinical tria
l.
S.Sanchis-Mora, Y.M.Chang, S.M.Abeyesinghe, A.Fisher, N.Upton, H.A.Volk,
L.Pelligand. Vet. J. July 2019; doi: 10.1016/j.tvjl.2019.06.006 Quote:
Highlights: •
Cavalier King Charles Spaniels
with
Chiari-like malformation/syringomyelia can have neuropathic pain. •
Pregabalin has efficacy in humans with neuropathic pain, and similarly
affected dogs could potentially benefit from the drug. • Pregabalin-treated
dogs showed improved owner-recorded daily pain scores using a numerical
rating scale. • Pregabalin improved mechanical hyperalgesia, cold
hyperalgesia at 0°C and cold allodynia at 15°C. • Pregabalin was efficacious
for the treatment of neuropathic pain caused by Chiari-like malformation and
syringomyelia in dogs. Abstract: Pregabalin is the first-line treatment for
neuropathic pain (NeP) in humans. Dogs with Chiari-like malformation and
syringomyelia (CM/SM) associated with NeP could benefit from pregabalin. The
aim of this study was to evaluate the efficacy of pregabalin for NeP in dogs
with CM/SM. ... Nine
Cavalier King Charles Spaniels
(four
males and five females) were recruited for the study from February 2016 to
August 2016 (Fig. 2). The median age was 6 years old (range, 1.1-9 years)
and the median bodyweight was 9.6 kg (range, 6.6-13.8 kg). All dogs
presented with cervical hyperaesthesia on palpation and five dogs showed
scratching behaviour, either phantom scratching or making contact with the
skin without evidence of skin/ear disease. ... Six dogs had a heart murmur.
... One dog dropped out of the study at day 7 of the first period due to an
ailment unrelated to the study. ... Eight dogs with symptomatic CM/SM were included in a
double-masked, randomised, crossover placebo-controlled clinical trial.
... The pregabalin formulation was the oral solution Lyrica (20 mg/mL,
bottle of 473 mL Pfizer). ... All
dogs received anti-inflammatory drugs as base-line treatment during placebo
or pregabalin phase of 14±4 days each. Analgesic efficacy was assessed with
a daily numerical rating scale (NRS) recorded by dog owners (0-10, 10=worst
pain) and quantitative sensory testing at baseline, placebo and pregabalin
phases. Blood samples were collected to report pregabalin exposure and to
assess renal function. Daily NRS scores recorded by dog owners in the
pregabalin group were lower than in the placebo group (P=0.006). Mechanical
thresholds were higher with pregabalin compared to baseline or placebo
(P=0.037, P<0.001). Cold latency at 15°C was prolonged on the neck and
humeri with pregabalin compared to baseline (P<0.001 for both) or placebo
(P=0.02, P=0.0001). Cold latency at 0 °C was longer on pregabalin compared
to baseline and placebo (P=0.001, P=0.004). There was no pregabalin
accumulation between first and last dose. This study demonstrates the
efficacy of pregabalin for the treatment of NeP due to CM/SM on daily pain
scores recorded by dog owners. Pregabalin significantly reduced mechanical
hyperalgesia, cold hyperalgesia (0°C) and allodynia (15°C) compared to
placebo. Pregabalin was non-cumulative and well tolerated with occasional
mild sedation.
Identifying and Treating Neuropathic Pain in Dogs with Syringomyelia
Ashley C. Hechler. Master's thesis, Ohio State Univ. July 2019. Quote:
Syringomyelia (SM) is a debilitating condition in the
cavalier King
Charles spaniel (CKCS)
that results in neuropathic pain and
diminished quality of life. Von Frey aesthesiometry (VFA) is a method of
mechanical quantitative sensory testing that provides an objective sensory
threshold (ST) value and can be used to quantify neuropathic pain and
monitor response to therapy. The utility of VFA has been previously
established in client-owned dogs with acute spinal cord injury and
osteoarthritis but the technique has not been evaluated in dogs with SM. The
goal of this study was to evaluate ST, as determined by VFA, in dogs with
and without SM, to assess the utility of VFA in quantifying NP in
SM-affected dogs. We hypothesized the SM-affected
CKCS
would have lower ST values consistent with hyperesthesia, when compared to
control
CKCS
. Additionally, we hypothesized that ST values
in SM-affected dogs would be inversely correlated with syrinx size on MRI
and with owner-derived clinical sign scores. ST values for the thoracic and
pelvic limbs differed significantly between SM-affected and control
CKCS
(p=0.027; p=0.0396 respectively). Median ST value (range) for
the thoracic limbs was 184.1 grams (120.9-552) for control dogs, and 139.9
grams (52.6-250.9) for SM-affected dogs. The median ST value (range) for the
pelvic limbs was 164.9 grams (100.8-260.3) in control dogs and 129.8 grams
(57.95-168.4) in SM-affected dogs. The ST values in SM-affected dogs did not
correlate with syrinx height on MRI (r=0.314; p=0.137). Owner-reported
clinical sign scores showed an inverse correlation with pelvic limb ST
values, where dogs with lower ST values (hyperesthesia) were reported by
their owners to display more frequent and severe clinical signs (r=-0.657;
p=0.022). ST values were lower in SM-affected
CKCS
compared
to control dogs, suggesting the presence of neuropathic pain. Dogs with
lower ST pelvic limb values were perceived by their owners to have more
severe clinical signs classically associated with SM. Our results suggest
that VFA may offer an objective assessment of neuropathic pain in
SM-affected dogs and could be useful for monitoring response to therapy in
future clinical studies. (See also this
September 2019 ACVIM Forum abstract
.)
Behavioral and clinical signs of Chiari-like malformation-associated pain
and syringomyelia in
Cavalier King Charles spaniels
Clare Rusbridge, Angus K. McFadyen, Susan P. Knower. J. v. Intern. Med. July
2019; doi: 10.1111/jvim.15552 Quote: Background: Diagnosis of Chiari-like
malformation-associated pain (CM-P) or clinically relevant syringomyelia
(SM) is challenging. We sought to determine common signs. ... The aim of
this study was to characterize retrospectively the clinical and behavioral
signs of CM-P and SM and relate these to maximum syrinx transverse diameter.
It is with a view to translating this data into a tool which can be used in
prospective studies into the treatment, diagnosis, and genetics of CM/SM.
... Animals: One hundred thirty client-owned
Cavalier King Charles
spaniels
with neuroaxis magnetic resonance imaging (MRI) and
diagnosis of CM-P/SM. Dogs with comorbidities causing similar signs were
excluded with exception of otitis media with effusion (OME). Methods:
Retrospective study of medical records relating signalment, signs, and MRI
findings. Dogs were grouped by SM maximum transverse diameter (1 = no SM; 2
= 0.5-1.99 mm; 3 = 2-3.9 mm: 4 = >4 mm). Differences between all
groups--groups 1 versus 2-4 and groups 1-3 versus 4--were investigated.
Continuous variables were analyzed using 2-sample t-tests and analysis of
variance. Associations between categorical variables were analyzed using
Fisher's exact or chi-square tests. Results: Common signs were vocalization
(65.4%), spinal pain (54.6%), reduced activity (37.7%), reduced
stairs/jumping ability (35.4%), touch aversion (30.0%), altered emotional
state (28.5%), and sleep disturbance (22%). Head scratching/rubbing (28.5%)
was inversely associated with syrinx size (P = .005), less common in group 4
(P = .003), and not associated with OME (P = .977). Phantom scratching,
scoliosis, weakness, and postural deficits were only seen in group 4
(SM >4mm; P = .004). ... Our results suggest any tool developed for
ascertaining quality of life in CM-P and SM should have specific questions
on signs suggesting discomfort, scratching/rubbing (including
character/site), sensitivity to touch, activity, ability to jump and climb
stairs, emotional state, and sleep. The study further suggests that
SM-specific signs are phantom scratching, scoliosis, and sensory and motor
signs that can be related to spinal cord damage by the syrinx and are
associated with large syringes (transverse width >4 mm). Non-SM-specific
signs include vocalization (described as without obvious trigger, when
shifting position when recumbent and when being lifted under the sternum to
a height), spinal pain, head and ear rubbing or scratching, aversion to
touch, refusal or difficulty jumping or doing stairs, exercise
intolerance/reduced activity, sleep disruption, or behavioral change
described as becoming more anxious, timid, aggressive, or withdrawn. These
non-SM-specific signs could reflect CM-P. Although possible variables for
the tool have been identified, interrelationships between them would have to
be taken into account in a multivariate sense when modeling. ... Conclusions
and Clinical Importance: Signs of pain are common in CM/SM but are not
SM-dependent, suggesting (not proving) CM-P causality. Wide (>4 mm) SM is
associated with signs of myelopathy and, if the dorsal horn is involved,
phantom scratching (ipsilateral) and torticollis (shoulder deviated
ipsilateral; head tilt contralateral).
(See also this April 2018 abstract.)
Network analysis of canine brain morphometry links
tumour risk to oestrogen deficiency and accelerated brain ageing
. Nina M.
Rzechorzek, Olivia M. Saunders, Lucy V. Hiscox, Tobias Schwarz, Katia
Marioni-Henry, David J. Argyle, Jeffrey J. Schoenebeck, Tom C . Freeman.
Nature Scientific Repts. August 2019;9:12506. Quote: Structural 'brain age' is a
valuable but complex biomarker for several brain disorders. The dog is an
unrivalled comparator for neurological disease modeling, however canine
brain morphometric diversity creates computational and statistical
challenges. Using a data-driven approach, we explored complex interactions
between patient metadata, brain morphometry, and neurological disease.
Twenty-four morphometric parameters measured from 286 canine brain magnetic
resonance imaging scans [25 (8.7%)
cavalier King Charles spaniels
] were
combined with clinical parameters to generate 9,438 data points. Network
analysis was used to cluster patients according to their brain morphometry
profiles. ...
CKCS
dogs were distinguished by their ventricular parameters
and cerebellar compression. ... Interestingly, 21 of 25
CKCS
dogs in our
cohort had intact septa, despite their high prevalence of Chiari-like
malformation. Conceptually, a compromised septum might increase ventricular
compliance and thus explain why Boxers are at low risk of Chiari-like
malformation and syringomyelia, despite shared ventricular morphology with
CKCSs
. ... Canine gliomas occur most commonly in brachycephalic breeds, with
the Boxer at highest risk. We noted a significant enrichment of brain
tumours with Boxers, however the absence of tumour diagnoses in
CKCS
dogs
resulted in non-enrichment of tumours within our brachycephalic category.
... Our findings suggest that advanced brain ageing enhances brain tumour
risk in dogs and may be influenced by oestrogen deficiency-a risk factor for
dementia and brain tumours in humans. Morphometric features of brain ageing
in dogs, like humans, might better predict neurological disease risk than
patient chronological age.
CSF omeprazole concentration and albumin quotient following high dose
intravenous omeprazole in dogs.
M. Giroda, F. Allerton, E.
Vangrinsven, A.C. Tutunaru, J. de Marchin, C. Gómez-Fernández-Blanco, A.
Ruiz-Nuño, A. Wojnicz, F. Farnir, K. Gommeren, D. Peeters. Res. in Vet. Sci.
August 2019; doi: 10.1016/j.rvsc.2019.07.009. Quote: Clinical signs of
syringomyelia and hydrocephalus occur secondary to cerebrospinal fluid (CSF)
accumulation within the central nervous system. Omeprazole is recommended to
treat these conditions despite little evidence of its capacity to decrease
CSF production in the dog. Studies into new treatments are hampered by
difficulties in measuring CSF production. The albumin quotient (QAlb), the
ratio between CSF and serum albumin concentrations, may reflect CSF
production and any decrease in CSF production should be associated with an
increase in QAlb. The primary objective of this study was to determine CSF
omeprazole concentration after administration of a high intravenous dose of
omeprazole and to evaluate its impact on QAlb in the dog. The second aim was
to validate QAlb as a surrogate marker of CSF production. Eighteen dogs were
included in this prospective crossover placebo-controlled study. Each dog
received omeprazole (10 mg/kg), acetazolamide (50 mg/kg) combined with
furosemide (1 mg/kg) and saline. Blood and CSF samples were obtained on day
0 and then every 7 days, one hour after drug administration. Omeprazole
concentrations (2.0 ± 0.4 μmol/L) reached in CSF after high dose omeprazole
were lower than the concentrations previously described as decreasing CSF
production in dogs. There was no significant increase in QAlb following
administration of acetazolamide/furosemide, prohibiting validation of QAlb
as a surrogate marker for CSF production. Several dogs presented transient
mild side effects after injection of acetazolamide/ furosemide. High dose
omeprazole was well tolerated in all dogs. ... Administration of a high dose
of omeprazole produced CSF omeprazole concentrations lower than those
previously reported to be effective at reducing CSF production in dogs. The
administration of acetazolamide in combination with furosemide was not
associated with an increase in QAlb one hour after administration when
compared to placebo administration. This suggests a lack of sensitivity of
QAlb as a surrogate marker of CSF production in dogs.
Mechanical Quantitative Sensory Testing in
Cavalier King Charles
Spaniels
with and without Syringomyelia
. Ashley Hechler,
Eric Hostnik, Laurie Cook, Lynette Cole, Sarah Moore. J. Vet. Intern. Med.
September 2019;doi: 10.1111/jvim.15597;#NO1:107. Quote: Syringomyelia (SM)
is a debilitating condition in
cavalier King Charles spaniels (CKCS)
resulting in clinical signs of neuropathic pain, such as hyperesthesia and
allodynia. Currently, advances in disease treatment are hindered by lack of
quantitative ways to assess neuropathic pain and monitor response to
therapy. We evaluated an electronic Von Frey aesthesiometer (VFA; IITC
Systems) to quantify sensory threshold (ST) abnormalities in SM. We
hypothesized that SM-affected dogs would have lower ST than controls,
consistent with hyperesthesia, and that ST would inversely correlate with
syrinx height and clinical signs scores. Twenty-nine
CKCS
with (n = 19) and without (n = 10) SM were enrolled. ST was measured by a
single investigator, blinded to disease status. ST was compared between
groups using Wilcoxin rank-sum. Associations between ST, clinical signs, and
imaging findings were evaluated by linear regression. Median ST (range) for
the thoracic limbs was 184.1 grams (120.9 - 552) for control, and 139.9
grams (52.6 - 250.9) for SM-affected dogs. Median ST for the pelvic limbs
was 164.9 grams (100.8 - 260.3) in control, and 129.8 grams (57.95 - 168.4)
in SM-affected dogs. ST for the thoracic and pelvic limbs was lower in
SM-affected dogs (p = 0.027; p = 0.0396), suggestive of hyperesthesia. ST in
SM-affected dogs did not correlate with syrinx height (r = 0.314; p =
0.137). Pelvic limb ST was inversely correlated with owner-derived clinical
sign scores, where dogs with lower ST displayed more severe clinical signs
(r = -0.657; p = 0.022). Our results suggest that VFA may offer an objective
assessment of hyperesthesia in SM-affected dogs and could be useful in
future studies to monitor response to therapy.
(See also this
July 2019 abstract
.) (See also this
March 2020 article
.)
Using machine learning to understand neuromorphological change and
image-based biomarker identification in
Cavalier King Charles
Spaniels
with Chiari-like malformation-associated pain and
syringomyelia
. Spiteri, M., Knowler, S.P., Rusbridge, C., Wells, K.
J. Vet. Intern. Med. September 2019; 10.1111/jvim.15621 . Quote: Background: Chiari-like
malformation (CM) is a complex malformation of the skull and cranial
cervical vertebrae potentially resulting in pain and secondary syringomyelia
(SM). CM associated pain can be challenging to diagnose. ["Machine-learning"
is a process of a computer not explicitly programmed by people, which looks
for patterns and data, then analyzes that information and draws conclusions
and makes predictions from that gathered information.] We propose a machine
learning approach to characterize morphological changes in dogs that may/may
not be apparent to human observers. This data driven approach can remove
potential bias (or blindness) that may be produced by a hypothesis driven
expert observer approach. Hypothesis/Objectives: Using a novel machine
learning approach to understand neuromorphological change and to identify
image-based biomarkers in dogs with CM associated pain (CM-P) and
symptomatic SM (SM-S), with the aim of deepening the understanding on these
disorders. Animals: 32 client owned
Cavalier King Charles Spaniels
(CKCS)
(11 controls, 10 CM-P, 11 SM-S). Methods: Retrospective
study using T2W midsagittal DICOM anonymized images which were mapped to a
images of a average clinically normal
CKCS
reference using
Demons image registration. Key deformation features were automatically
selected from the resulting deformation maps. A kernelized Support Vector
Machine was used for classifying characteristic localized changes in
morphology. Results: Candidate biomarkers were identified with receiver
operating characteristic (ROC) curves with area under the curve (AUC) of
0.78 (sensitivity = 82%; specificity = 69%) for the CM-P biomarkers
collectively, and an AUC of 0.82 (sensitivity = 93%; specificity = 67%) for
the SM biomarkers collectively. Conclusions and clinical importance: Upon
comparing dogs with CM-P to a control group, the main regions identified as
diagnostically relevant candidate biomarkers for this condition are: the
floor of the third ventricle and closely associated neural tissue, and the
region in sphenoid bone (pre-sphenoid and basisphenoid) around the sella
turcica. There are also lesser areas of interest in caudal nasal cavity
close to the dorsal cribriform plate, between the soft palate and the
tongue, on the tip of the odontoid process. The main regions were identified
as diagnostically relevant biomarkers when comparing dogs with a specific
diagnosis of SM to a control group are: the pre-sphenoid bone and the region
between the soft palate and the tongue. It is worth noting that both
experiments have yielded biomarkers in the presphenoid bone and area between
the soft palate and the tongue, which indicates both conditions being
strongly related to changes within this area. Further work will explore the
further development of the image registration process, which in turn is
expected to improve the AUC values. This study has shown we can successfully
discriminate between CM-P subjects and those without, and for those with
SM-S, and those without, using a set of biomarkers discovered using machine
learning. This work can be used as a basis to build a clinical diagnostic
test based on registering these key locations in a query subject back to the
equivalent landmarks on a reference subject free of such pathology. Further
analysis could be done to investigate whether a link exists between disease
severity and the magnitude of the neuro-morphological distortion indicated
by these biomarkers. Developing these biomarkers into a clinical diagnostic
test is the topic of on-going work.
Facial changes related to brachycephaly in
Cavalier King Charles
Spaniels
with Chiari‐like malformation associated pain and
secondary syringomyelia
. Susan P. Knowler, Eleonore Dumas, Michaela
Spiteri, Angus K. McFadyen, Felicity Stringer, Kevin Wells, Clare Rusbridge.
J. Vet. Intern. Med. November 2019; doi: 10.1111/jvim.15632. Quote:
Background: Recent studies including an innovative machine learning
technique indicated Chiari-like malformation (CM) is influenced by
brachycephalic features. Objectives: Morphometric analysis of facial anatomy
and dysmorphia in CM-associated pain (CM-P ) and syringomyelia (SM) in the
Cavalier King Charles Spaniel (CKCS)
. Animals: Sixty-six
client-owned
CKCS
. Methods: Retrospective study of
anonymized T2W sagittal magnetic resonance imaging of 3 clinical groups: (1)
11 without central canal dilation (ccd) or SM (CM-N), (2) 15 with CM-P with
no SM or <2 mm ccd (CM-P), and (3) 40 with syrinx width >4 mm (SM-S).
Morphometric analysis assessed rostral skull flattening and position of the
hard and soft palate relative to the cranial base in each clinical group and
compared CKCS with and without SM‐S. Results: Sixteen of 28 measured
variables were associated to SM-S compared to CM-N and CM-P. Of these 6 were
common to both groups. Predictive variables determined by discriminant
analysis were (1) the ratio of cranial height with cranial length (P<.001
between SM-S and CM-N) and (2) the distance between the cerebrum and the
frontal bone (P<.001 between SM-S and CM-P). CM-P had the lowest mean height
of the maxillary area. Conclusions and Clinical Importance:
CKCS
with CM-P and SM-S have cranial brachycephaly with osseous insufficiency in
the skull with rostral flattening and increased proximity of the hard and
soft palate to the cranial base. Changes are greatest with CM-P. These
findings have relevance for understanding disease pathogenesis and for
selection of head conformation for breeding purposes.
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2020
Pregabalin alleviates clinical signs of syringomyelia-related central
neuropathic pain in
Cavalier King Charles Spaniel
s - a
randomised controlled trial
. Maria S. Thoefner, Lene T. Skovgaard,
Fintan J. McEvoy, Mette Berendt, Ole J. Bjerrum. Vet. Anaesth. & Analgesia.
March, 2020;47(2):238-248. Quote: Objective: We aimed to
assess the efficacy and benefit-risk profile of pregabalin to reduce the
clinical signs of central neuropathic pain as reflected by scratching
episodes in dogs with symptomatic syringomyelia. Study design: Randomized,
double-blind, placebo-controlled crossover study. Animals: A total of 12
client-owned
Cavalier King Charles Spaniels
(1.1-7.4 years
old, bodyweight 8.2-10.8 kg) with magnetic resonance imaging-confirmed
syringomyelia and clinical signs of central neuropathic pain. Methods:
Randomization of dogs to either pregabalin 150 mg or placebo for 25 days and
48-hours wash-out before crossover to the alternate phase of 25 days
duration. The primary outcome was defined as number of scratching events
during 10 minutes of video recorded physical activity. Treatment effect was
estimated using a generalised estimation equations model. Benefit-risk and
quality of life assessments were obtained through owner interviews focusing
on potential adverse events. Results: The treatment effect estimate was an
84% (95% confidence interval = 75%-89%) reduction in mean number of
scratching events relative to baseline when compared to placebo (p <
0.0001). Owner-assessed satisfactory quality of life was status quo and
rated as 'good' or 'could not be better' in 6/11 dogs and improved in 4/11
dogs. The most prevalent adverse events were increased appetite in 9/12 dogs
and transient ataxia in 9/12 dogs. There was one dog withdrawn by the owner
7 days after crossover to pregabalin owing to persistent ataxia. No dogs
needed rescue analgesia during the trial. Conclusion and clinical relevance:
Pregabalin is superior to placebo in the reduction of clinical signs of
syringomyelia-related central neuropathic pain in dogs. At a dose range of
13-19 mg kg-1 orally twice daily the encountered adverse events were
acceptable to all but one owner.
Mechanical quantitative sensory testing in
cavalier King Charles
spaniels
with and without syringomyelia
. Ashley
C.
Hechler, Eric T. Hostnik, Laurie B. Cook, Lynette K. Cole, Sarah A. Moore.
BMC Vet. Res. March 2020; dio: 10.1186/s12917-020-02313-7. Quote:
Background: Syringomyelia (SM) is a debilitating condition in the
cavalier King Charles spaniel (CKCS)
that results in neuropathic
pain and diminished quality of life. Von Frey aesthesiometry (VFA) is a
method of mechanical quantitative sensory testing that provides an objective
sensory threshold (ST) value and can be used to quantify neuropathic pain
(NP) and monitor response to therapy. The utility of VFA has been previously
established in client-owned dogs with acute spinal cord injury but the
technique has not been evaluated in dogs with SM. The goal of this study was
to evaluate ST, as determined by VFA, in dogs with and without SM, to assess
the utility of VFA in quantifying NP in SMaffected dogs. We hypothesized the
SM-affected CKCS would have lower ST values, consistent with hyperesthesia,
when compared to control
CKCS
. Additionally, we
hypothesized that ST values in SM-affected dogs would be inversely
correlated with syrinx size on MRI and with owner-derived clinical sign
scores. ... Nineteen 19 SM-affected [MRI evidence] and 10 control
CKCSs
[no MRI evidence of SM] were enrolled. ... Control dogs
ranged from 1 to 2 years of age (median 1.5 years) and SM-affected dogs
ranged from 1 to 8 years of age (median 4 years). SM-affected dogs were
significantly older than control dogs, but the sex did not differ
significantly between groups. ... Results: ST values for the thoracic and
pelvic limbs differed significantly between the SM-affected and control
CKCS
. Median ST value (range) for the thoracic limbs was
184.1g (120.9-552) for control dogs, and 139.9g (52.6-250.9) for SM-affected
dogs. The median ST value (range) for the pelvic limbs was 164.9g
(100.8-260.3) in control dogs and 129.8g (57.95-168.4) in SM-affected dogs.
The ST values in SM-affected dogs did not correlate with syrinx height on
MRI (r=0.314;p=0.137). Owner-reported clinical sign scores showed an inverse
correlation with pelvic limb ST values, where dogs with lower ST values
(hyperesthesia) were reported by their owners to display more frequent and
severe clinical signs. Conclusion: ST values were lower in SM-affected
CKCS
compared to control dogs, suggesting the presence of
neuropathic pain. Dogs with lower ST pelvic limb values were perceived by
their owners to have more severe clinical signs classically associated with
SM. Our results suggest that VFA might offer quantitative assessment of
neuropathic pain in SM-affected dogs and could be useful for monitoring
response to therapy in future clinical studies.
(See also this
September 2019 abstract
.)
The effect of phenotypic selection on fourteen years of chiari-like
malformation and syringomyelia MRI scanning in
Cavalier King Charles
Spaniels
in the Netherlands
Laterveer, M. Utrecht Univ.
master thesis. March 2020. Quote: Chiari-like malformation (CM) and
Syringomyelia (SM) is an inherited disease complex which is common in the
Cavalier King Charles Spaniels (CKCS)
. Since 2004 a
law-enforced obligatory screening program prior to breeding is used to
achieve a healthier population of Dutch
CKCS
. This study
evaluated the effect of phenotypic selection by combining pedigree data and
screening results of two to three generations of dogs to see if there is any
improvement in the breeding stock. In total, 572 MRI scans from 518 dogs
were prospectively enrolled if they were screened between January 1st 2016
and December 31st 2018. CM and PSOM (primary secretory otitis media) were
scored and SM was defined as unaffected (CCD (central canal dilation) of 0
mm) or affected (CCD of >0 mm). The prevalence of SM in this study was 22.7%
and increased with age clearly demonstrating the age-effect of SM. The
prevalence of middle ear effusion in the left ear was 19.4% and in the right
ear 20.0%. Results indicated that selecting unaffected parents leads to a
lower CCD in offspring. This reduction in CCD is even more if parents with
healthier grandparents are given priority. Conversely, the offspring of
affected parents was more likely to have an increase in CCD. CM and PSOM did
not improve upon screening for unaffected parents. It is concluded that, the
obligatory screening for and subsequent selection for older unaffected CKCS,
the offspring indeed improved each generation and as indicated by a reduced
prevalence of Syringomyelia.
Medical infrared thermal imaging of syringomyelia in the
Cavalier
King Charles Spaniel
. Michael Larkin, Catherine Loughin,
Dominic Marino, Curtis Dewey, Scott Umbaugh, Joseph Sackman. BMC Vet. Res.
May 2020;16:137. doi: 10.1186/s12917-020-02354-y  Quote: Background: Medical infrared
thermal imaging (MITI), also known as medical infrared imaging (MII) or
infrared thermography (IRT), is a noninvasive imaging modality used for
screening purposes in human medicine and gaining popularity in veterinary
medicine. ... MITI requires use of a specific camera that captures emission
of heat from the surface of objects, such as skin. Topical heat emission is
influenced by localized disease processes as a result of autonomic nervous
system imbalance. The purpose of this study was to determine the utility of
using thermography to identify changes in thermographic patterns associated
with syringomyelia (SM) presence or absence in
Cavalier King Charles
Spaniels (CKCS)
with Chiari-like Malformation (CLM). ... One
hundred dogs were included in this study. Due to poor image quality (usually
motion artifact) preventing proper interpretation on some of the MITI
images, seven of the dogs were eliminated totaling 93
CKCS
in this study. Of the 93
CKCS
included, the average age was
33.7 months old (SD = 27.4 months) and the average weight of each patent was
8.1kg (17.8 pounds). There were 35 female intact (37.6%), 24 female spayed
(25.8%), 15 male intact (16.1%) and 19 male neutered (20.4%)
CKCS
Of the 93
CKCS
included in this study, all (100%) had CLM
based on complete, full-body MR imaging; 48 (51.6%) were diagnosed with SM
and 45 (48.4%) had no evidence of SM. ... Results: In
CKCS
with CLM, MITI was most accurate at a texture distance of 6. Optimizing
imaging feature sets produced a highest accuracy of 69.9%, with 81.3%
sensitivity and 57.8% specificity for identifying the presence of
syringomyelia. Conclusion: Thermographic image analysis is a successful
non-invasive, diagnostic test that can be used to screen for syringomyelia
presence in a
CKCS
with CLM. ... This study revealed that
MITI is a successful screening test for the presence of SM in CKCS with CLM.
Compared to other imaging modalities, MITI is a quick, inexpensive modality
that does not require sedation nor anesthesia, and eliminates radiation
exposure (to patient & staff). MITI does not provide insight to syrinx
location or severity nor should it be used as a sole diagnostic modality.
While veterinary thermographic imaging continues to improve as advances in
technology occur, MRI will remain the gold standard for definitive diagnosis
and staging of Chiari-like malformation and syringomyelia.
(Fig. 1 --
Thermograms of CKCS: Left image is CKCS without SM; right image is CKCS with
SM.)
Comparison of high-field MRI and multidetector CT for grading Chiari-like
malformation and syringomyelia in
Cavalier King Charles Spaniels
Sarah M Weber, Eric T Hostnik, Wm Tod Drost, Alessandra N Hamlin, Marc A
Ledesma, Lauren Timperman, Ashley C. Hechler, Lynette K Cole. Vet. Radiol. &
Ultrasound. April 2020;doi: 10.1111/vru.12862. Quote: Chiari-like
malformation (CM) and syringomyelia (SM) are common illnesses that can cause
debilitating neuropathic pain in
Cavalier King Charles spaniels
(CKCS)
. The current imaging modality to screen
CKCS
for CM/SM is MRI of the brain and cervical spine. Magnetic resonance imaging
provides good soft tissue detail and contrast of the cerebellum and cervical
spinal cord. Computed tomography (CT) is another cross-sectional imaging
technique that facilitates brain and neck evaluation; however, soft tissue
resolution does not match that of MRI. Computed tomography benefits include
identification of concurrent craniocervical junction anomalies
(atlantooccipital overlap) and shorter imaging/ anesthesia times with the
ability to use only sedation. The aim of this retrospective, method
comparison study is to assess the utility of multidetector CT for screening
CM and SM in
CKCS
as compared to high-field MRI. Three
groups of observers with different levels of experience graded CM and SM
based on the British Veterinary Association/Kennel Club CM/SM classification
criteria. Thirty
CKCS
underwent multidetector CT and 3
Tesla MRI studies. Computed tomography and MRI studies were reviewed at
different timepoints to minimize bias. Computed tomography has lower Cohen's
Kappa agreement for each observer group compared to MRI. The intraclass
correlation coefficient averaging CM and SM for all groups was excellent
using MRI, while CT was poor for SM and moderate for cerebellar herniation.
... Computed tomography is financially cheaper, shorter in acquisition time,
more accessible to general practitioners, and requires less anesthetic
drugs/time. Results of this study support the hypothesis that the overall
agreement and the agreement between observer groups of similar experience
levels is higher using 3T MRI compared to multidetector CT. The second
hypothesis related to sensitivity, specificity, and accuracy had mixed
results. The average sensitivity and accuracy for diagnosis of cerebellar
herniation and SM using MRI was higher than CT. ... The higher accuracy,
though only slight, using CT for identifying cerebellar herniation counters
our hypothesis that MRI is a better tool for CM evaluation. The lower
inter-rater agreement for diagnosis of cerebellar herniation using CT
relative to MRI indicates that though accuracy is slightly higher, the
observers were not arriving to the same consensus regarding each individual
case. Also, the slight difference in accuracy may not be a clinically
significant difference. The more accurate identification of SM using MRI
does support the hypothesis of MRI as a better tool for identifying neural
pathology. ... The specificity for identifying cerebellar herniation was
similar between MRI and CT. The average specificity for identifying SM was
higher using CT compared to MRI. The third hypothesis regarding experience
was not completely supported by the results. Sensitivity, specificity, and
accuracy for MRI of DACVR [radiology diplomate] B, as well as the average
sensitivity, specificity, and accuracy for CT findings of the ACVR observers
were higher than the lesser-experienced groups of observers. However, the
average sensitivity, specificity, and accuracy of the veterinary interns and
secondyear residents were similar with the veterinary interns slightly
higher than the residents. ... Greater observer experience resulted in a
higher agreement for CT and MRI. Magnetic resonance imaging should remain
the standard for screening of CM and SM as CT can result in
misclassification and greater disagreement.
New considerations about Chiari-like malformation, syringomyelia and their
management
. Clare Rusbridge. InPractice. June 2020;42(5):252-267; doi:
10.1136/inp.m1869 Quote: Background: Chiari-like malformation (CM) is a
developmental condition, characterised by a conformational change and
overcrowding of the brain and cranial cervical spinal cord. CM-associated
pain (CM-P) and syringomyelia are increasingly being diagnosed, due to the
rising popularity of predisposed brachycephalic breeds and the availability
of MRI in veterinary practices. Aim of the article: This article aims to
update the veterinary profession on these conditions, and provides a guide
to diagnosis and treatment of clinically relevant disease. ... The condition
is most common in
Cavalier King Charles spaniels (CKCS)
and
their crosses (eg, cavapoos), especially if the cross is with a smaller dog
than a
CKCS
Retrospective Study of 240 Dogs Receiving Gabapentin for Chronic Pain Relief
Lily V Davis, Peter W Hellyer, Robin A Downing, Lori R Kogan. J. Vet.Med. &
Research. August 2020;7(4):1194-1197. Quote: Our goal was to assess
gabapentin dosage and tolerability in dogs taking it for chronic pain. ...
All patients in this study were on gabapentin due to an inability to fully
control their pain with NSAIDs or nutraceuticals alone. ... The majority
(217 patients; 90.42%) had pain localized to their back. The other anatomic
locations of pain included stifle (33; 13.8%), elbow/shoulder (21; 8.8%) and
hip (11; 4.6%). Some patients' pain was localized to multiple areas and is
counted in all categories. The most common diagnosis of pain was
osteoarthritis (203; 84.6%), followed by generalized, nonspecific back pain
(22;9.2%), intervertebral disk disease (18; 7.5%), and degenerative
myelopathy (11; 4.6%). Some patients experienced two different kinds of pain
and are embodied in both categories. One hundred and thirty-six (56.67%)
patients did not have definitive anatomic cause for their pain, such as
cruciate tears or intervertebral disc disease, as seen in Table 2. ... We
retrospectively analyzed the medical records of 240 dogs taking gabapentin
for chronic pain and systematically assessed: patient signalment, definitive
diagnosis, location and description of pain, VAS scores immediately
preceding and following the patient's maximum gabapentin dose, maximum
gabapentin dosage, presence or absence of side effects related to gabapentin
use, use of NSAID/immunomodulator drugs and nutraceuticals, presence or
absence of levothyroxine supplementation, surgical procedures, and physical
medicine. The range of tolerated gabapentin doses was 6.9 - 500 mg/kg/day
[3.1- 227.3 mg/lb], PO, q12 hr (every 12 hrs) and only 10% of patients
experienced the most common side effect of sedation. ... The results from
this case series suggest that gabapentin is well-tolerated at much higher
doses than what is typically prescribed. Side effects were uncommon, with no
clear pattern based on dose, or dog size or age. Therefore, like many other
analgesic medications, the efficacy of gabapentin appears patient-specific
and should be dosed to effect until side effects are noted or analgesia is
achieved.
The effect of combined carprofen and omeprazole administration on
gastrointestinal permeability and inflammation in dogs
. Susan M.
Jones, Ann Gaier, Hiroko Enomoto, Patricia Ishii, Rachel Pilla, Josh Price,
Jan Suchodolski, Joerg M. Steiner, Mark G. Papich, Kristen Messenger, M.
Katherine Tolbert. J. Vet. Intern. Med. September 2020; doi:
10.1111/jvim.15897. Quote: Background: Proton pump inhibitors (eg,
omeprazole) commonly are administered concurrently with nonsteroidal
anti-inflammatory drugs (NSAIDs; eg, carprofen) as prophylaxis to decrease
the risk of gastrointestinal (GI) injury. However, evidence to support this
practice is weak, and it might exacerbate dysbiosis and inflammation.
Hypothesis/Objectives: To evaluate the effect of carprofen alone or combined
with omeprazole in dogs. We hypothesized that coadministration of omeprazole
and carprofen would significantly increase GI permeability and dysbiosis
index (DI) compared to no treatment or carprofen alone. Animals: Six healthy
adult colony beagle dogs. Methods: Gastrointestinal permeability and
inflammation were assessed by serum lipopolysaccharide (LPS) concentration,
plasma iohexol concentration, fecal DI, and fecal calprotectin concentration
in a prospective, 3-period design. In the first 7-day period, dogs received
no intervention (baseline). During the 2nd period, dogs received 4 mg/kg of
carprofen q24h PO for 7 days. In the 3rd period, dogs received 4 mg/kg of
carprofen q24h and 1 mg/kg of omeprazole q12h PO for 7 days.
Gastrointestinal permeability testing was performed at the end of each
period. Data were analyzed using repeated measures mixed model analysis of
variance with Tukey-Kramer post hoc tests. Results: Serum LPS and plasma
iohexol concentrations did not differ between treatments. Fecal calprotectin
concentrations differed between treatments. The DI varied over time based on
the treatment received. Co-administration of omeprazole and carprofen
significantly increased fecal calprotectin concentration and DI compared to
baseline and carprofen alone. Conclusions and Clinical Importance:
Omeprazole prophylaxis induces fecal dysbiosis and increases intestinal
inflammatory markers when coadministered with carprofen to otherwise healthy
dogs with no other risk factors for GI bleeding. ... The increase in fecal
DI when dogs were given carprofen and omeprazole PO suggests that addition
of omeprazole had a negative impact on the fecal microbiome, and in turn may
negatively impact intestinal health. ... Whether carprofen plays a
substantial role in the induction of dysbiosis or inflammation when
coadministered with omeprazole cannot be determined from our study because
we did not include a treatment group in which dogs received omeprazole
alone. ... [Other studies have shown that] Carprofen-induced injury to the
gastroduodenal mucosa is generally mild and resolves quickly after drug
discontinuation. ... Based on previous studies in which omeprazole caused
intestinal dysbiosis in dogs and the lack of dysbiosis or inflammation with
carprofen alone in our study, we believe that omeprazole is the major driver
of fecal dysbiosis and intestinal inflammation and, although further study
is needed, may result in development of NSAID-induced enteropathy, as
previously determined in other species.
Clinical reasoning in canine cervical hyperaesthesia: which presenting
features are important
. Nicholas John Grapes, Rowena Mary Anne
Packer, Steven De Decker. Vet. Rec. November 2020; doi: 10.1136/vr.105818.
Quote: Background: To evaluate whether clinical features from the history,
presentation, physical and neurological examination of dogs with cervical
hyperaesthesia are statistically predictive of the underlying diagnosis.
Methods: Two hundred and ninety‐eight dogs presenting with cervical
hyperaesthesia between January 2010 and October 2018 were investigated. ...
The study population consisted of 54 diferent breeds with 38 crossbreeds.
The most prevalent breeds were
Cavalier King Charles spaniels
(n=49), French bulldogs (n=31), beagles (n=27), labradors (n=18) and cocker
spaniels (n=10). Of the French bulldogs within the study population, 84 per
cent (n=26) were diagnosed with IVDE, while 88 per cent (n=43) of
Cavalier King Charles spaniels
studied were diagnosed with SM
[syringomyelia]. ... Only neurologically normal dogs with cervical
hyperaesthesia on examination were included, while those with concurrent
neurological deficits including gait abnormalities and proprioceptive
deficits were excluded. Univariate analysis of clinical variables was
performed, and those associated with each diagnosis were retained for
multivariable binary logistic regression models. Results: Ninety-five per
cent of cervical hyperaesthesia presentations were represented by eight
conditions that included steroid-responsive meningitis arteritis (SRMA;
n=100 - 33.6%), intervertebral disc extrusion (n=78 - 26.2%), syringomyelia
(SM; n=51 - 17.1%), intervertebral disc protrusion (n=30 - 10.1%), neoplasia
(n=8 - 2.7%), cervical spondylomyelopathy (n=7 2.3%), immune‐mediated
polyarthritis (n=5 - 1.7%) and meningoencephalomyelitis of unknown aetiology
(n=5 - 1.7%). ... 88 per cent of
Cavalier King Charles spaniels
presenting with cervical hyperaesthesia during the study period were
diagnosed with SM. SM was most commonly episodic in its progression.
Although the most obvious clinical signs to the owner such as phantom
scratching or vocalisation may be intermittent or episodic, recent research
has identiied that persistent signs of discomfort including reduced
activity, reluctance to jump or climb stairs, emotional changes and
aversions to being touched are common in dogs with Chiari-like malformation
and SM. ... Conclusions: Easy-to-recognise clinical features can be used to
identify the most likely differential diagnosis in neurologically normal
dogs with cervical hyperaesthesia, which may aid the decision making of
veterinary surgeons evaluating dogs with this presentation.
Quantification of cerebrospinal fluid flow in dogs by cardiac-gated
phase-contrast magnetic resonance imaging
. Muriel A. Christen,
Daniela Schweizer-Gorgas, Henning Richter, Fabiola B. Joerger, Matthias
Dennler. J. Vet. Intern. Med. December 2020; doi: 10.1111/jvim.15932. Quote:
Background: Cerebrospinal fluid (CSF) flow in disease has been investigated
with two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI)
in humans. Despite similar diseases occurring in dogs, PC-MRI is not
routinely performed and CSF flow and its association with diseases is poorly
understood. Objectives: To adapt 2D and four-dimensional (4D) PC-MRI to dogs
and to apply them in a group of neurologically healthy dogs. Animals: Six
adult Beagle dogs of a research colony. Methods: Prospective, experimental
study. Sequences were first optimized on a phantom mimicking small CSF
spaces and low velocity flow. Then, 4D PC-MRI and 2D PC-MRI at the level of
the mesencephalic aqueduct, foramen magnum (FM), and cervical spine were
performed. Results: CSF displayed a bidirectional flow pattern on 2D PC-MRI
at each location. Mean peak velocity (and range) in cm/s was 0.92
(0.51-2.08) within the mesencephalic aqueduct, 1.84 (0.89-2.73) and 1.17
(0.75-1.8) in the ventral and dorsal subarachnoid space (SAS) at the FM, and
2.03 (range 1.1-3.0) and 1.27 (range 0.96-1.82) within the ventral and
dorsal SAS of the cervical spine. With 4D PC-MRI, flow velocities of >3 cm/s
were visualized in the phantom, but no flow data were obtained in dogs.
Conclusion: Peak flow velocities were measured with 2D PC-MRI at all 3
locations and slower velocities were recorded in healthy Beagle dogs
compared to humans. These values serve as baseline for future applications.
The current technical settings did not allow measurement of CSF flow in
Beagle dogs by 4D PC-MRI.
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2021
Association between filum terminale internum length and pain in
Cavalier King Charles spaniels
with and without syringomyelia
Courtney R. Sparks, Christian Woelfel, Ian Robertson, Natasha J. Olby. J.
Vet. Intern. Med. January 2021; doi: 10.1111/jvim.16023. Quote: Background:
Lumbar syringomyelia (SM), lumbosacral pain, and more caudal spinal cord
termination are reported in
Cavalier King Charles spaniels (CKCS)
Data are lacking on the clinical relevance of alterations in their spinal
cord terminal structures. ... The normal spinal cord tapers to a relatively
elastic structure called the filum terminale internum, composed of
ependymal, pial and glial cells and surrounded by the subarachnoid space and
dural sac. Distally, the dural sac closes down onto the filum, creating a
more fibrous tether, called the filum terminale externum. This structure
fuses with the periosteum of the caudal (Cd) vertebrae, thus anchoring the
meninges and spinal cord within the vertebral canal. ... Objectives: To
compare spinal cord termination level and filum terminale internum length
(FTIL) with presence of lumbar SM and clinical signs in CKCS. Animals:
Forty-eight
CKCS
. ... Twenty-three of 48 dogs (48%) did
not have SM, 2 dogs had cervical SM only (4%), 1 dog had lumbar SM only
(2%), and 22 dogs had both cervical and lumbar SM (46%). All dogs with
lumbar SM also had thoracic SM. The cohort consisted of 16 (33%) normal
dogs, 12 (25%) asymptomatic dogs with SM, 7 (15%) symptomatic dogs without
SM (CM-pain), and 13 (27%) symptomatic dogs with SM.  ... Methods: In this prospective study, pain
was quantified using owner and clinician assessments. ... We hypothesized
that symptomatic
CKCS
with CM with or without SM would have
a significantly more caudal termination of their spinal cord than do
asymptomatic dogs. Our aims were first to describe and compare the site of
spinal cord and dural sac termination in symptomatic and asymptomatic
CKCS
, and second to quantify and compare the length of the
filum terminale internum between these 2 groups of dogs. ... Vertebral level
of spinal cord and dural sac termination, presence of SM, and FTIL were
determined from sagittal magnetic resonance imaging (MRI) sequences. Kappa
and intraclass correlation (ICC) analyses determined interobserver
reliability. The MRI findings were compared to owner and clinician-reported
pain quantification. Results: Interobserver reliability was good for spinal
cord and dural sac termination and excellent for FTIL. The spinal cord
terminated at 6th lumbar vertebra in 1, 7th lumbar vertebra in 31, and the
sacrum in 15 dogs, and termination level was associated with lumbar SM but
not clinical signs. Mean FTIL was 2.9 ±1.08 mm; it was associated with
owner-reported pain and spinal palpation scores. Painful
CKCS
without SM had shorter FTIL compared to normal
CKCS
and
painful
CKCS
with SM. Conclusions: Painful
CKCS
without SM have decreased distance between the termination of the spinal
cord and dural sac, suggesting a shorter FTIL. More caudal spinal cord
termination is associated with development of lumbar SM. ... In summary, the
purpose of our work was to determine if caudal spinal abnormalities in
CKCS
were associated with clinical signs of pain and
scratch. We disproved our hypothesis that a more caudal location of spinal
cord termination would be associated with clinical signs. However, we found
that FTIL is associated with pain, not scratch, and our work supported
previous findings that the vertebral level of the spinal cord termination is
associated with lumbar SM. In addition, we found that painful dogs without
SM were differentiated from other phenotypes by a decreased FTIL. These
findings show that location of the filum terminale is associated with
development of lumbar SM and FTIL is associated with spinal pain in
CKCS
. Future work is warranted to characterize other caudal
clinical and functional abnormalities, potentially by use of gait analysis,
electro-physiological evaluation of the conus medullaris, and urodynamic
studies in these dogs. (See also this
June 2018 abstract
.)
Frequency of phantom scratching in Cavalier King Charles Spaniels (CKCS)
assessed by owner questionnaire before and during maropitant treatment
Emma Gilbert, Sandra Sanchis Mora, Ludovic Pelligand, Lydia Poad, Holger
Volk, Clare Rusbridge. BSAVA Congress 2021: Clinical abstract presentation.
January 2021; doi: 10.22233/9781913859039.26. Quote: Study basis: The
superficial dorsal horn was previously found to be affected in
CKCS
with syringomyelia with the clinical sign of phantom scratching. The NK-1
receptors located in this area are considered as a target for treatment for
fictive [phantom] itch. We aimed to assess outcomes with 2 weeks maropitant
treatment (NK-1 R antagonist) on frequency of phantom scratching. Results:
Population: 9
CKCS
, mean age 6.1 years (range 3-10), 3
males (1 entire, 2 neutered) and 6 females (1 entire, 5 neutered). The most
common site that the syrinx involved the superficial dorsal horn was the
level of C3 or C4 vertebrae. Following treatment with maropitant mean scores
for questions on frequency of phantom scratching decreased. Wilcoxon Rank
sign analysis was significant in 4/6 of these questions. Spontaneous
scratching, scratching while walking, scratching when groomed, scratching
when touched. Discussion: VAS scores were difficult for owners to complete
without guidance with only 3/9 being completed (though notably all giving a
decreased score consistent with improvement), we therefore excluded them
from the results of our study. This trial was open label, and therefore
subject to caregiver bias, placebo effect and high owner expectation. Owners
were happy with maropitant as a treatment for chronic disease due to its low
side effect profile. Further investigation with a placebo controlled
crossover study is needed next to confirm this initial evidence for a
positive effect to decrease frequency of phantom scratching in dogs and the
lack adverse effects found with treatment with this licensed veterinary
product.
The Need for Head Space: Brachycephaly and Cerebrospinal Fluid Disorders
Clare Rusbridge, Penny Knowler. Life. February 2021; doi:
10.3390/life11020139. Quote: Brachycephalic dogs and cats are predisposed to
cerebrospinal fluid (CSF) circulation disorders, such as ... Chiari-like
malformation, and syringomyelia. ...
Cavalier King Charles spaniels
with syringomyelia associated with Chiari-like malformation have smaller
volume jugular foramina compared to
Cavalier King Charles spaniels
without syringomyelia. However, direct causality between smaller jugular
foramen and syringomyelia has not been proven. ... [C]raniosynostosis
[premature closure of cranial sutures, preventing continued growth to
accommodate the growing size of the brain] may be associated with a primary
venous abnormality.
Cavalier King Charles spaniels
with
syringomyelia associated with Chiari malformation have reduced volume caudal
cranial fossa dorsal sinuses. ... Chiari-like malformation associated pain
in dogs describes a syndrome of pain associated with brachycephaly and
hindbrain herniation. It is often compared to Chiari type I and 0
malformation in humans. However, it is more like the hindbrain herniation
seen with syndromic and complex craniosynostosis in humans, for example,
Crouzon's and Pfeiffer syndrome. ... In comparison to dogs with Chiari-like
malformation only, dogs with syringomyelia have more extreme brachycephaly
with craniocervical junction deformation, including cervical flexure, change
in angulation of the odontoid peg, increased proximity of the atlas to the
skull (often referred to as atlanto-occipital overlapping), kinking or
elevation of the craniospinal junction, and loss of the cisterna magna.
Changes in conformation of the spinal canal and cord may also contribute.
The authors propose that syringomyelia develops due to a combination of
reduced CSF absorption though nasal lymphatics, reduced venous drainage,
altered neuroparenchymal compliance, and reduced CSF movement through the
lateral apertures or craniocervical junction. Curvature of the spinal canal
and intrathoracic pressure gradient may contribute especially in the
thoracic spinal cord. The mechanism of development of syringomyelia is
controversial. The most accepted theory is that subarachnoid space
obstruction results in a mismatch in timing between the arterial pulse peak
pressure and CSF pulse peak pressure. ... Dogs and cats with neonatal
characteristics of a reduced muzzle and brachycephaly have impaired CSF
[cerebrospinal fluid] circulation, which predisposes ventriculomegaly,
hydrocephalus, quadrigeminal cistern expansion, Chiari-like malformation
associated pain, and syringomyelia.
Histologic findings of the dura mater at the level of the foramen magnum in
121
CKCS
with Chiari-like malformation
. Jaclyn P.
Holdsworth, Dominic J. Marino, Catherine A. Loughin, Andrew D. Miller,
Joseph J. Sackman, Martin L Lesser, Marissa O'Donnell. ResearchSquare. March
2021; doi: 10.21203/rs.3.rs-314710/v1. Quote: Background: To describe
histopathologic features found in dural biopsies of
Cavalier King
Charles Spaniels (CKCS)
with Chiari-like malformation (CM) and
identify any associations between age, duration of clinical signs, syrinx
location or syringomyelia (SM) and quality of life (QOL). The medical
records of 121 consecutive client owned
CKCS
with CM and
SM, confirmed by whole body magnetic resonance imaging (MRI), that underwent
foramen magnum decompression (FMD) with cranioplasty and durectomy with
biopsy from 2006 to 2016 were retrospectively reviewed. Dura biopsies were
submitted to a board-certified veterinary pathologist for histopathologic
interpretation. The chi-square test was used to analyze associations between
diagnosis and categorical variables. For continuous measures, the
Kruskal-Wallis non-parametric test was used to compare distributions across
pathology categories. A result was considered statistically significant at
the P<0.05 level of significance. Results: The mean age, duration of
pre-surgical clinical signs, and pre-operative QOL (1-5 scale) were 44.27
months, 44.78 weeks, and 2.72 respectively. Syringomyelia was found in the
cervical region only in thirty-nine of one hundred twenty-one (32.23%) of
dogs, in the cervical and thoracic region only in seventeen of one hundred
twenty-one (14.05%) of dogs, and in the cervical, thoracic and lumbar region
combined in sixty-five of one hundred twenty-one (53.72%) of dogs. Sixty-six
of one hundred twenty-one (54.55%) dural biopsy specimens had histopathology
changes; fifty-five (45.45%) did not. Forty-three of one hundred twenty-one
(35.54%) dural biopsy specimens had osseous metaplasia, sixteen of one
hundred twenty-one (13.22%) had evidence of fibrosis, four of one hundred
twenty-one (3.31%) had arachnoid hyperplasia, and three of one hundred
twenty-one (2.48%) had evidence of mineralization. Conclusions: The majority
of dogs with CM were found to have histopathologic changes in the dura at
the time of FMD cranioplasty was performed. These dural changes can be
observed in dogs experiencing clinical signs for a time period as short as
four weeks prior to presentation. Histopathologic changes were not
associated with age, breed, duration of clinical signs, the location of
syringomyelia or preoperative QOL. The influence of histopathologic changes
on long term prognosis in dogs without dural decompression is unknown since
all dogs in this study had dural resection.
Syringomyelia and Myxomatous Mitral Valve Disease in
Cavalier King
Charles Spaniels
. Maiken B.T. Bach, C.L. Stougaard, M.S.
Thofner, M.J. Reimann, U. Westrup, J. Koch, M. Fredholm, T. Martinussen,
M.Berendt, L.H. Olsen. 2021 ACVIM Forum. June 2021; C-12. Quote:
Cavalier King Charles spaniels (CKCS)
are genetically predisposed
to both syringomyelia (SM) and myxomatous mitral valve disease (MMVD). This
study investigated if a possible association between the occurrence of the
two diseases exists. This combined retrospective and prospective study
running 2007-2015 included 55
CKCS
: Forty-one dogs with
syrinx identified with MRI, defined by a hypointense area in T1 > 2mm in
width, and 14 controls ( > 5 years of age) with no syrinx on MRI. Of dogs
with SM, 19 dogs were asymptomatic while 22 were symptomatic.
Echocardiography ( > 4 years of age) were performed in all dogs. A possible
association between syringomyelia and MMVD disease severity (left ventricle
internal diameter in diastole (LVIDD), LVIDD normalized to bodyweight
(LVIDDN) and left atrium to aortic ration (LA:Ao)) was tested using
multivariable linear regression analysis adjusting for sex and age. There
was no significant difference in LVIDD, LVIDDN and LA:Ao (median [IQR])
between
CKCS
with SM (28.20 [27.0-30.80], 1.50 [1.40-1.60],
1.20 [1.10-1.40]) and
CKCS
without SM (28.90 [27.15-36.75],
1.55 [1.43-1.83], 1.30 [1.20-1.80]). Yet, LVIDD, LVIDDN and LA:Ao were
smaller in
CKCS
with symptomatic SM (27.20 [25.85-28.80],
1.45 [1.30-1.50] and 1.20 [1.10-1.28]) compared to
CKCS
with asymptomatic SM (30.80 [28.40-38.40] p < 0.001, 1.60 [1.50-1.90] p <
0.001, 1.40 [1.20-1.75]). We found no overall association between MMVD and
SM. Dogs affected with symptomatic SM had less severe MMVD compared to dogs
with asymptomatic SM indicating it is important to be aware of both diseases
when breeding
CKCS
Ventriculomegaly in
Cavalier King Charles Spaniels
with
Chiari-like Malformation: Relationship with Clinical Signs and Imaging
Findings
. F. Tirrito, F. Cozzi, S. Corazzo, B. Contiero, R.
Lombardo. 33d ESVN-ECVN Symposium 2021, #P-30. September 2021. Vet. Intern.
Med. December 2021; doi: 10.1111/jvim.16332.  Quote:
Chiari-like malformation (CM) frequently occurs in
Cavalier King
Charles Spaniels (CKCS)
. Ventriculomegaly, secondary to disturbance
of cerebrospinal fluid flow at the craniocervical junction, has been
reported in
CKCS
with CM. However, its clinical relevance
is unclear. The aim of the study was to calculate lateral ventricles
dimension in
CKCS
with CM and to investigate the
association between ventriculomegaly and signalment, clinical signs,
ventricular asymmetry, CM and syringomyelia (SM) grade, medullary kinking
index, follow-up, and epileptic seizures. A retrospective study was
performed enrolling forty-three client-owned
CKCS
with
magnetic resonance imaging diagnosis of CM. Initial and follow-up (up to 36
months) clinical status was graded. Images were reviewed to quantify
dimension of lateral ventricles, to evaluate ventricular symmetry, CM and SM
grade, and medullary kinking index. Cases presenting epileptic seizures were
also recorded. The most common initial clinical signs were scratching and
neck pain. Ventriculomegaly was identified in 70% of dogs, CM grade 2 was
observed in 77% of cases, ventricular asymmetry and syringomyelia were
identified in 54% and 80% of dogs, respectively; median medullary kinking
index was 37.77%. Moreover, 28% of dogs presented epileptic seizures. No
significant association was identified between dimension of lateral
ventricles and signalment, clinical signs, and imaging findings; no
significant association was identified between ventriculomegaly and
epilepsy. In conclusion, the prevalence of ventriculomegaly in
CKCS
with CM is high but this finding does not seem related to the severity of
clinical signs, to CM/SM, to medullary kinking index, and to epileptic
seizures.
Successful Pain Management after Filum Terminale Internum De-tethering in 2
CKCS
with Chiari-like Malformation
. Ane Uriarte,
Abby McElroy, Petra Klinge. 33d ESVN-ECVN Symposium 2021, #P-79. September 2021.
Vet. Intern. Med. December 2021; doi: 10.1111/jvim.16332. Quote:
Cavalier King Charles Spaniels (CKCS)
are
affected by Chiari-like malformation (CM) and syringomyelia (SM) causing
neuropathic chronic pain. Severely affected cases fail to respond to medical
management and occipital cranioplasty is often recommended. Clinical relapse
of neuropathic pain is recorded in a high number of cases treated with this
surgical approach. An association between Chiari I malformation (CM1) and
tethered cord syndrome in human patients presenting post failed CM1 surgery
is recognised (Milhorat et al., 2009). For these patients, de-tethering of
the filum terminale internium may be effective in relieving symptomatology,
restoring normal brain stem length, normalizing the position of the
cerebellar tonsils, and in some cases, avoiding the need for posterior fossa
surgery (Milhorat et al 2009).
CKCS
have a caudally
displaced spinal cord and dural sac when compared with a range of
weight-matched breeds
(Sparks at al., 2019)
. Additionally, painful
CKCS
without SM have been found to have a shorter filum terminale internum
(Sparks at al., 2020)
. Two
CKCS
affected with CM had a
successful resolution of pain following de-tethering surgery, including a
7-year-old who relapsed after occipital cranioplasty and a 1-year-old with
no previous surgery. The filum terminale internum was sectioned via a dorsal
laminectomy without complications and both animals were free of pain,
without medication, for 20 and 7 months respectively at the time of writing.
Follow up MRI was performed on one dog. De-tethering of the filum terminale
internum will remain controversial until definitive treatment guidelines are
established in human and veterinary medicine.
Foramen magnum decompression and modified cranioplasty using titanium mesh
plate in small dogs with caudal occipital malformation syndrome and
syringomyelia
. Yukiko Nakano, Y. Nozue, K. Nakata, S. Kimura, H.
Kamishina. 33d ESVN-ECVN Symposium 2021, #O-22. September 2021. Vet. Intern.
Med. December 2021; doi: 10.1111/jvim.16332. Quote:
Foramen magnum decompression (FMD) is one of the surgical treatments of
Chiari malformation type 1 in humans. FMD is also a treatment option for
caudal occipital malformation syndrome (COMS) and syringomyelia in dogs.
Cranioplasty (CP) is combined with FMD to prevent postoperative scar tissue
formation that compresses the FMD site. However, adequate decompression may
not be achieved in small-breed dogs with reported surgical procedures
because of the potential risk of damage of the transvers sinus. We performed
modified [much wider] FMD+CP in small-breed dogs [3 chihuahuas and 2 toy
poodles] and retrospectively investigated the clinical outcomes and
complications. Informed consent was obtained from owners of all dogs prior
to surgeries. We performed modified FMD+CP in 5 dogs with COMS and
syringomyelia. The occipital bone was removed widely with a great care not
to damage the transvers sinus. A pre-contoured titanium mesh plate was
placed over the bone defect and secured to the parietal and temporal bones
with screws. Procedures were completed without any intraoperative
complication in all dogs. Complete resolution of clinical signs was seen in
2 dogs. Cerebellar symptoms such as ataxia and hypermetria remained in three
dogs, but QOL of these dogs was improved and the owners were satisfied with
the outcome. Three-month postoperative follow-up MRI performed in 3 dogs
[all chihuahuas] revealed considerable reduction of the syrinx size. In
conclusion, modified FMD+CP is a safe procedure and leads to considerable
reduction of the syrinx in small-breed dogs. This procedure is expected to
reduce the risk of recurrence of foramen magnum compression and syrinx
formation by postoperative scar tissues.
Diffusion Tensor Imaging in Syringomyelia Secondary to Chiari Malformation
in
Cavalier King Charles Spaniel
. Preliminary Study
A. Banasik, Karolina Owsińska-Schmidt, W. Krupińska, A. Zimny, M. Wrzosek.
33d ESVN-ECVN Symposium 2021, #O-21. September 2021. Vet. Intern. Med.
December 2021; doi: 10.1111/jvim.16332. Quote: The aim of this
study was to find a correlation between clinical assessment and diffusion
tensor imaging (DTI) values in the course of Syringomyelia. Sixteen
Cavalier King Charles Spaniel
dogs, (eight in the symptomatic and
eight in the asymptomatic group), 6-70 months of age (mean 36), 3.5-9.5 kg
(mean 7.2), were qualified for the research. All animals underwent the same
study protocol that included a clinical and neurological examination
followed by MRI examination. DTI was performed with a 1,5 Tesla magnetic
resonance scanner (Philips, Ingenia). Two DTI parameters: fractional
anisotropy (FA) and apparent diffusion coefficient (ADC) were measured.
Measurement of FA and ADC values was made by drawing regions of interest
(ROIs) at the level of three intervertebral spaces (C1-C4) in both
sympthomatic and asympthomatic group. Image post-processing was done using
the Fiber Trak package (Philips Ingenia workstation). Statistical analysis
showed no significant differences in FA and ADC values between the
symptomatic and asymptomatic groups. However, decreased FA values were
observed in ROI-2 and ROI-3 in the symptomatic group compared to the
asymptomatic group. Compared to the asymptomatic group, in the symptomatic
group in ROI-1 the same ADC values were observed, while in ROI-2 and ROI-3
an increase in ADC values was noted. Findings suggest that DTI could be a
helpful technique in the study of syringomyelia in
Cavalier King
Charles Spaniel
, in content of anticipation of eventual development
of clinical symptoms in young dogs. DTI values measurements may provide more
objective spinal cord microstructure and indirectly also status assessment.
(See also this December 2022 article on the same study.)
Slosh Simulation in a Computer Model of Canine Syringomyelia
Srdjan Cirovic, Clare Rusbridge. Life. October 2021; doi:
10.3390/life11101083. Quote: The exact pathogenesis of syringomyelia is
unknown. Epidural venous distention during raised intrathoracic pressure
(Valsalva) may cause impulsive movement of fluid ("slosh") within the
syrinx. Such a slosh mechanism is a proposed cause of syrinx dissection into
spinal cord parenchyma resulting in craniocaudal propagation of the cavity.
We sought to test the "slosh" hypothesis by epidural excitation of CSF
[cerebrospinal fluid] pulse in a computer model of canine syringomyelia. Our
previously developed canine syringomyelia computer model was modified to
include an epidural pressure pulse. ... The model geometry was extracted
from magnetic resonance imaging (MRI) scans of a
CKCS [cavalier King
Charles spaniel
] with a Chiari-like malformation and a fully
developed syrinx. Cardiac pulse excitation of CSF motion was simulated for a
fully patent and a fully occluded foramen magnum, with the latter
representing the extreme case of CSF pathway obstruction due to Chiari-like
malformation. When the foramen magnum was fully patent, the model predicted
mechanical stress in the spinal cord to be of the same magnitude as the CSF
pressure (order of magnitude of 102 Pa). When the foramen magnum was
obstructed, the stress values in the cranial cervical region and the
cervico-thoracic junction increased by nearly 100%; these are also the
regions where initial syringes form in dogs. While the absolute values of
mechanical stress predicted by the model were probably too low to cause any
immediate damage to the spinal cord tissue, abnormally high stress was
clearly correlated with typical anatomical locations at which syringes
initially form. Without trying to explain the exact mechanism(s) for syrinx
formation and growth, we hypothesize that they can be associated with the
stress in the spinal cord being significantly elevated from the values that
would normally be generated by common excitations such as the cardiac pulse
and filling of the epidural veins. In this study, we build on the above
hypothesis to examine the situation where small initial syringes have
already formed in the spinal cord tissue. The focus is on the excitation of
CSF movement caused by the filling of epidural veins, which can potentially
generate the "slosh" effect leading to syrinx expansion. ... Simulations
were run for: cord free of cavities; cord with small syringes at different
locations; and cord with a syrinx that was progressively expanding caudally.
If small syringes are present, there are peaks of stress at those locations.
This effect is most pronounced at the locations at which syringes initially
form. When a syrinx is expanding caudally, the peak stress is typically at
the caudal end of the syrinx. However, when the syrinx reaches the lumbar
region; the stress becomes moderate. The findings support the "slosh"
hypothesis, suggesting that small cervical syringes may propagate caudally.
However, when the syrinx is large, there is less focal stress, which may
explain why a syrinx can rapidly expand but then remain unchanged in shape
over years. ... Conclusions: The results of this study strongly suggest that
the spinal cord tissue in the vicinity of fluid-filled cavities experiences
higher than normal mechanical stress due to the movement of the CSF from
epidural excitation. When the syringes are longer than approximately 30 mm,
filling of the epidural veins may generate the "slosh" effect, where the
fluid is forced to the caudal end of the syrinx. The results for the
simulations of an expanding syrinx are broadly consistent with the
homeostatic hypothesis, as the stress in the cord is lower for the fully
developed syrinx than for smaller syringes. Other, potentially more
realistic, scenarios for syrinx expansion should be examined in the future.
This study specifically addresses syringomyelia in dogs, and more
specifically in
CKCS
. ... Considering anatomical and other
differences (e.g., upright posture in humans) the results regarding the
potential pattern of syrinx enlargement do not apply to humans or to dog
breeds other than
CKCS
RETURN TO TOP
2022
Occipital cranioplasty using customized titanium prosthesis yields
successful outcome in association with foramen magnum decompression in dogs
suffering by Chiari-like malformation
. Alessia S. Colverde, Tommaso
Nicetto, Cristian Falzone. Am. J. Vet. Res. February 2022; doi:
10.2460/ajvr.21.11.0178. Quote: Objective: To describe the use of a
customized 3-D-printed titanium prosthesis as adjunctive treatment for
foramen magnum decompression (FMD) in dogs with Chiari-like malformation
(CM) and syringomyelia (SM). Animals; 8 dogs [6
cavalier King
Charles spaniels
(75%)] with clinical signs and MRI findings
of CM-SM. Procedures: 3-D reconstruction of CT images of the head was used
to simulate an occipital craniectomy and design the prosthesis.
[See
figures A and B.]
FMD was performed, and the prosthesis was implanted.
Follow-up
was performed 1, 6, and 12 months later, and clinical status was scored.
Repeated MRI images were compared to identify changes involving the neural
structures, particularly the syrinx. Results: All prostheses were easily
positioned based on the preoperative 3-D models, with no complications. At
12 months after surgery, 3 dogs were free of previous medications [
CKCS
Cases 2, 3, & 7], 4 were still receiving steroid medications but at lower
doses [
CKCS
Cases 5 & 6], and 1 was occasionally receiving
acupuncture. MRI of 5 dogs 6 to 20 months after surgery revealed resolution
of SM (n = 1) [
CKCS
Case 7], reduced size of SM (3) [
CKCS
Cases 2 & 4], or worse SM (1) [
CKCS
Case 6]. ...
Case 2
CKCS
female intact, age 34 months: On
presentation: Chiari-malformation (CM) grade 2 (cerebellum impacted or
herniated through foramen magnum (FM); syrinx (SM) location & size: C2-C4, 5
mm.; clinical signs: Grade 2 (mild neuropathic pain); duration of clinical
signs: 1 year; post-surgery results: 1 month follow-up: Grade 0 (no pain and
phantom scratching); 6 month follow-up: Grade 0; 12 month follow-up: Grade
0; 47 month follow-up: Grade 0; MRI follow-up at 20 months: CM: 0; SM:
C2-C3, 3.5 mm.
Case 3
CKCS
female intact,
age 25 months: On presentation: CM grade 1 (cerebellum indented, not
rounded); SM location & size: C3, 1.2 mm.; clinical signs: Grade 3 (moderate
neuropathic pain); duration of clinical signs: 2 months; Grade 3 (moderate
neuropathic pain) on presentation; 1 month follow-up: Grade 0; 6 month
follow-up: Grade 0; 12 month follow-up: Grade 0; 40 month follow-up: Grade
0; no MRI follow-up.
Case 5
CKCS
female
intact, age 21 months: On presentation: CM grade 2; syrinx (SM) location &
size: C2-C5, 4 mm.; clinical signs: Grade 2; duration of clinical signs: 10
months; post-surgery results: 1 month follow-up: Grade 0; 6 month follow-up:
Grade 1; 12 month follow-up: Grade 1; 31 month follow-up: Grade 1; no MRI
follow-up.
Case 6
CKCS
female intact, age 36
months: On presentation: CM grade 2; syrinx (SM) location & size: C2-L1, 5.7
mm.; clinical signs: Grade 3; duration of clinical signs: 2 years;
post-surgery results: 1 month follow-up: Grade 0; 6 month follow-up: Grade
1; 12 month follow-up: Grade 1; 23 month follow-up: Grade 3; MRI follow-up
at 19 months: CM: 0; SM: C1-L1, 6.4 mm.
Case 7
CKCS
female neutered, age 48 months: On presentation: CM grade 2; syrinx (SM)
location & size: C3-C4, 5.7 mm.; clinical signs: Grade 3; duration of
clinical signs: 1.5 years; post-surgery results: 1 month follow-up: Grade 0;
6 month follow-up: Grade 0; 12 month follow-up: Grade 0; 16 month follow-up:
Grade 0; MRI follow-up at 9 months: CM: 0; SM: none.
Case 8
CKCS
male neutered, age 77 months: On presentation: CM
grade 2; syrinx (SM) location & size: C2-L5, 7.3 mm.; clinical signs: Grade
4 (severe neuropathic pain); duration of clinical signs: 5 years;
post-surgery results: 1 month follow-up: Grade 1; 6 month follow-up: Grade
1; 12 month follow-up: Grade 1; no MRI follow-up. ...
All dogs showed an
increase in size of the caudal cranial fossa. Dogs with a longer presurgical
duration of the clinical signs and wider syrinx generally had worse outcomes
than other dogs. Clinical Relevance: Findings suggested that use of
customized 3-D-printed titanium prosthesis and associated FMD can represent
an adjunctive option to medically treated dogs with CM-SM. Although the
small number of cases precludes definitive conclusions, early surgical
treatment, particularly in dogs with a small syrinx, could ensure better
long-term outcomes, as previously suggested.
Nasal Septum Deviation in dog breeds predisposed to Chiari-like malformation
associated pain and syringomyelia
. Clare Rusbridge, J. R.
Rusbridge. BSAVA Congress 2022. March 2022. Quote: Nasal Septum deviation in
breeds predisposed to Chiari-like malformation associated pain and
syringomyelia. Objectives: Nasal septum deviation (NSD) and Chiari-like
malformation pain and syringomyelia (CMSM) are common in flat-faced
brachycephalic dogs. NSD may be clinically irrelevant but has been
associated with sleep disordered breathing (SDB) in humans and dogs. SDB
affects glymphatic drainage of cerebrospinal fluid which could predispose
CMSM. This study investigated possible correlation between NSD and CMSM
Methods Study population - 76 dogs with head CT [computed tomography] and
known CMSM status (based on MRI and medical history). Comprising 53
CKCS [cavalier King Charles spaniels
] (70%) (7 CM-N [CM-clinically
normal] i.e. MRI determined breed-associated CM but clinically normal; 14
with CM-P [CM-associated pain] but no SM; 32 with SM); 12 Chihuahua (5 MRI
and clinically normal, 7 with SM); 11 other brachycephalic toy dog breeds
and crosses (10 with SM). Transverse CT of the nasal cavity in bone windows
was reviewed. Presence of a NSD was recorded. Previously described method of
determining the angle of NSD was not reproducible and consequently
abandoned. The NSD ratio calculated (maximum distance of NSD from midline/
distance from midline to nasal cavity wall). Results NSD was almost
ubiquitous; Only 3 dogs had a midline nasal septum without deviation (1
Chihuahua, 1
CKCS
, 1 Cavapoo; all 3 were CMSM affected).
There was no correlation between NSD ratio and CMSM (signs of pain or
presence of syringomyelia). Impact NSD is common in dog breeds predisposed
to CMSM. Care should be taken before attributing clinical relevance.
Association of NSD to CMSM is unproven. More extreme brachycephaly is
associated with both NSD, CM-P and SM and therefore the conditions may
co-exist. Airway obstruction, SDB and apnoea may be relevant in the
pathogenesis of CMSM or be a important comorbidity. More sophisticated
methods of investigation are recommended for example polysomnography to
monitor respiratory effort.
Dorsal horn volume loss and pain pathway changes in
Cavalier King
Charles Spaniels
with syringomyelia, signs of pain, and phantom
scratching
. Danny Mortensen, Maria Soendergaard Thoefner, Joergen
Steen Agerholm, Lasse Slumstrup, Troels Staehelin Jensen, Ole Jannik
Bjerrum, Mette Berendt, Jens Randel Nyengaard. Pain. March 2022; doi:
10.1097/j.pain.0000000000002630. Quote: Central neuropathic pain is a core
clinical sign of syringomyelia in humans and
Cavalier King Charles
Spaniel (CKCS)
dogs. This histopathological study used spinal cords
from
CKCS
with syringomyelia to investigate: 1) whether
specific structural cervical spinal cord entities involved in nociception
are affected by loss of neuroparenchyma or other pathological changes in
CKCS
with pain-related behaviour and phantom scratching, 2)
if pain related behaviour or phantom scratching correlated with loss of a
specific anatomical entity or upregulation of glia cells, and 3) if
syringomyelia-related lesions affected specific functional spinal cord units
of nociception. Spinal cord segments C1-C8 from
CKCS
with
MRI-confirmed syringomyelia and clinical signs of pain and phantom scratch
(n=8) were compared to
CKCS
without syringomyelia (n=4).
Dogs with unilateral scratching (n=7) had a volume loss of the dorsal horn
laminae I-III in the ipsilateral side compared to the contralateral dorsal
horn. A clear pattern of ipsilateral changes in the dorsal root entry zone
characterised by deafferentation and reorganization of first-order axons
into deeper laminae was found in cases with lateralised scratching.
Significant changes in cell number density were not found for astrocytes or
microglia, suggesting that the dogs represented cases of end-stage
syringomyelia and thus could not reveal astrogliosis and microgliosis, which
may be involved in the early phases of syrinx development and phantom
scratch. The present relationship between clinical findings and dorsal horn
and pain pathway pathology in
CKCS
suggests that these dogs
may be of interest as a supplement to experimental model pain research.
Ventriculomegaly in
Cavalier King Charles Spaniels
with
Chiari-like malformation: relationship with clinical and imaging findings
Federica Tirrito, Francesca Cozzi, Martina Bonaldi, Stefania Corazzo,
Barbara Contiero, Rocco Lombardo. J. Vet. Med. Sci. July 2022; doi:
10.1292/jvms.22-0134. Quote: The objective of this study was to calculate
lateral ventricles dimension in
Cavalier King Charles Spaniel
dogs with Chiari-like malformation and investigate the association between
ventriculomegaly and signalment, clinical signs, ventricular asymmetry,
grade of Chiari-like malformation, syringomyelia and index of medullary
kinking. Retrospectively, 43 client-owned
Cavalier King Charles
Spaniels
, older than 1 year of age, with magnetic resonance imaging
diagnosis of Chiari-like malformation were enrolled. ... Twenty-eight (65%)
dogs were male and 15 (35%) were female. The percentage of male dogs was
significantly higher than females. ... Initial and follow-up (up to 36
months) clinical status was graded. Images were reviewed to quantify the
enlargement of lateral ventricles, evaluate ventricular symmetry, grade of
Chiari-like malformation, grade of syringomyelia and medullary kinking
index. Cases presenting epileptic seizures during the evaluation period were
also recorded. The most common initial clinical signs were scratching and
neck pain. Ventriculomegaly was identified in 70% of dogs, Chiari-like
malformation grade 2 [(CM2); cerebellum impacted or herniated through the
foramen magnum] was observed in 77% of cases, ventricular asymmetry and
syringomyelia were identified in 54% and 80% of dogs, respectively; the
median medullary kinking index was 37.77%. Moreover, 28% of dogs presented
epileptic seizures. ... No significant association was identified between
grade of SM and class of ventriculomegaly. ... No significant association
was identified between dimension of lateral ventricles and signalment,
clinical signs, and imaging findings; no significant association was
identified between ventriculomegaly and epilepsy. ... Finally, no
significant association was found between medullary kinking index and class
of ventriculomegaly in our population of dogs. ... Primary secretory otitis
media [OME] is frequently described in
CKCS
and the
reported clinical signs may be similar to those described in dogs with CM.
Interestingly, no relationship between OME and clinical signs was found in
our population. These results are concordant with previous literature and it
is possible that otitis media is a consequence of the brachycephalic
conformation of
CKCS
, but the clinical significance of the
disease is unclear. ... In conclusion, the prevalence of ventriculomegaly in
Cavalier King Charles Spaniels
is high but this finding
does not seem related to the severity of clinical signs, presence of
Chiari-like malformation, syringomyelia and craniocervical junction
abnormalities such as medullary kinking. 2023
Biopsy and histologic findings of the dura mater at the level of the foramen
magnum in 121
CKCS
with Chiari-like malformation
Jaclyn P. Holdsworth, Dominic J. Marino, Catherine A. Loughin, Andrew D.
Miller, Joseph J. Sackman, Martin L. Lesser, Marissa O'Donnell. Front. Vet.
Sci. September 2022; doi: 10.3389/fvets.2022.954092. Quote: To describe
histopathologic features found in dural biopsies of
Cavalier King
Charles Spaniels (CKCS)
with Chiari-like malformation (CM) and
identify any associations between age, duration of clinical signs, syrinx
location or syringomyelia (SM), and quality of life (QOL). The medical
records of 121 consecutive client owned
CKCS
with CM and
SM, confirmed by whole body magnetic resonance imaging (MRI), that underwent
foramen magnum decompression (FMD) with cranioplasty and durectomy with
biopsy from 2006 to 2016 were retrospectively reviewed. Dural biopsies were
submitted to a board-certified veterinary pathologist for histopathologic
interpretation. The chi-square test was used to analyze associations between
histologic findings and categorical variables. For continuous measures, the
Kruskal-Wallis non-parametric test was used to compare distributions across
pathology categories. A result was considered statistically significant at
the p < 0.05 level of significance. The mean age, duration of pre-surgical
clinical signs, and pre-operative QOL (1-5 scale) were 44.27 months, 44.78
weeks, and 2.72, respectively. Syringomyelia was found in the cervical
region only in 39 of 121 (32.23%) of dogs, in the cervical and thoracic
region only in 17 of 121 (14.05%) of dogs, and in the cervical, thoracic,
and lumbar region combined in 65 of 121 (53.72%) of dogs. Sixty-six of one
hundred twenty-one (54.55%) dural biopsy specimens had histopathology
changes; fifty-five (45.45%) did not. Forty-three of one hundred twenty-one
(35.54%) dural biopsy specimens had osseous metaplasia, 16 of 121 (13.22%)
had evidence of fibrosis, 4 of 121 (3.31%) had arachnoid hyperplasia, and 3
of 121 (2.48%) had evidence of mineralization. Most dogs with CM were found
to have histopathologic changes in the dura at the time of FMD cranioplasty
was performed. These dural changes can be observed in dogs experiencing
clinical signs for a time period as short as 4 weeks prior to presentation.
The histopathologic changes were not associated with age, breed, duration of
clinical signs, the location of syringomyelia or QOL. The influence of
histopathologic changes on long-term prognosis in dogs without dural
decompression is unknown since all dogs in this study had dural resection.
Diffusion Tensor Imaging in Syringomyelia Secondary to Chiari Malformation
in
Cavalier King Charles Spaniel
-- A Preliminary Study
Marcin Adam Wrzosek, Aleksandra Ewa Banasik, Karolina Owsińska‐Schmidt, Anna
Zimny. Animals. December 2022; doi: 10.3390/ani12233405. Quote:
Syringomyelia secondary to Chiari‐like malformation (so‐called CM‐SM
syndrome) is a common disorder in
Cavalier King Charles Spaniels
(CKCS)
that is diagnosed using standard structural MRI, though
imaging findings often do not correlate with the severity of clinical
symptoms. Diffusion tensor imaging (DTI) is a technique that defines subtle
microstructural changes in the course of many brain and spinal cord
diseases, that are not visible on standard MRI. The aim of the study was to
identify the correlation between the presence of clinical symptoms and DTI
parameters, such as apparent diffusion coefficient (ADC) and fractional
anisotropy (FA) within the spinal cord in the course of CM-SM. ... To our
knowledge, this is the first report evaluating DTI parameters in dogs with
syringomyelia use in the clinical setting. ... We hypothesized that DTI
would be a good candidate for prediction regarding the prevalence of the
symptomatic CM-SM course and that this would be of great value in canine and
human patients. ... Study subjects included 18 dogs,
CKCS
with MRI‐confirmed SM (SM group), and 12
CKCS
dogs without
SM (non-SM group). The SM group was divided into SM‐symptomatic group (n =
8) and SM-asymptomatic group, n = 10). All dogs underwent same clinical and
neurological assessment followed by MRI examination. All MRI studies were
performed on a 1.5T MRI scanner. The MRI spine protocol included: transverse
and sagittal T2-weighted images followed by DTI performed in the sagittal
plane. The measurements of FA and ADC values were performed manually using
the region of interest (ROI) method at the level of three intervertebral
discs between C1 and C4. Notable differences in age and body weight were
found. No significant differences in FA and ADC values between the SM and
non-SM groups were found, but between non- SM, SM-asymptomatic and
SM-symptomatic groups significant differences were found in ADC values in
all three ROIs and in FA values in ROI-1 and ROI-3. SM-symptomatic dogs
compared to no-- SM, showed decreased FA value in ROI-1 and ROI-3 also
increased ADC value in ROI-1, ROI-2 and ROI-3. SM-symptomatic dogs compared
to SM-asymptomatic showed also decreased FA value in ROI-1 and ROI-3, and
also increased ADC value in ROI-1, ROI-2 and ROI-3. The results suggest that
the values of DTI parameters correlate with the severity of clinical
symptoms in the course of CMSM in animals. The use of DTI evaluation of
CM-SM patients carries a potential value as a clinically relevant protocol
for an objective assessment of the spinal cord.
(See also this September 2021 article on the same study.)
RETURN TO TOP
2023
Three-dimensional kinematics of the craniocervical junction of
Cavalier King Charles Spaniels
compared to Chihuahuas and
Labrador retrievers
. Mareike-Kristin Nickel, Lisa Schikowski,
Martin Stephan Fischer, Nicola Kelleners, Martin Jürgen Schmidt, Nele
Eley. PLoS ONE. January 2023; doi: 10.1371/journal.pone.0278665. Quote:
Our knowledge about the underlying pathomechanisms of craniocervical
junction abnormalities (CCJA) in dogs mostly derives from measurements
based on tomographic imaging. These images are static and the
positioning of the dogs' head does not reflect the physiological in vivo
position of the craniocervical junction (CCJ). Aberrant motion patterns
and ranges of motion (ROM) in sound individuals of CCJA predisposed
breeds may be a pathogenetic trigger. To further extend our limited
knowledge of physiological motion of the CCJ, this prospective,
comparative study investigates the in vivo motion patterns and ROM of
the CCJ in walk and trot in [15] sound
Cavalier King Charles
Spaniels
and [15] Chihuahuas. The Labrador retriever [14 of
them] is used as a reference breed without predisposition for CCJA. This
is the first detailed description of CCJ movement of trotting dogs.
Biplanar fluoroscopy images, recorded in walking and trotting dogs, were
matched to a virtual reconstruction of the skull and cranial cervical
spine utilising Scientific Rotoscoping. ... Scientific Rotoscoping is a
markerless and therefore non-invasive kinematic gait analysis method of
XROMM methodology (X-Ray Reconstruction of Moving Morphology). The
technique merges motion data from biplanar X-ray videos with skeletal
morphology data from CT scans and creates 3D bone animations moving in
3D space. Scientific Rotoscoping is considered a methodology generating
anatomically highly accurate animations, also for use in dogs and the
spine in particular. Highly precise and accurate motion measurements are
enabled, although the technique is very elaborate and time consuming.
... Kinematic data reveal the same motion patterns among all breeds and
gaits with individual temporal and spatial differences in each dog. A
stride cycle-dependent lateral rotation of the cranial cervical spine
and axial rotation of the atlantoaxial joint in trot in dogs is
described for the first time. The ROM of the atlantoaxial and
atlantooccipital joints in walk and trot were not statistically
significantly greater in the CCJA-predisposed breeds
CKCS
and Chihuahua. ROM values of all translational and rotational degrees of
freedom were larger in walk than trot, although this is only
statistically significant for the atlantoaxial joint. Until proven
otherwise, a more species-specific than breed-specific general motion
pattern of the CCJ in walking and trotting, clinically sound dogs must
be assumed. Species-specific anatomic properties of the CCJ seem to
supersede breed-specific anatomical differences in clinically sound
dogs.
Chiari-like malformation in
Cavalier King Charles Spaniels
impacts brainstem auditory-evoked response latency results
Lynette K. Cole, Susan O. Wagner, Sarah A. Moore, Ronaldo DaCosta,
Eric T. Hostnik, Laura E. Selmic. Am. J. Vet. Res. May 2023; doi:
10.2460/ajvr.23.03.0064. Quote: Objective: To evaluate hearing loss
in
Cavalier King Charles Spaniels (CKCS)
breed-specific brainstem auditory-evoked response (BAER) testing
parameters are needed to help assess the Chiari-like malformation
(CM) grade. The purpose of this study was to establish
breed-specific BAER data and to determine if BAER indexes differed
based on the CM grade. We hypothesized that there would be latency
differences based on the CM grade. Animals: 20
CKCS
without apparent hearing abnormalities as assessed by the owners.
Procedures: Under general anesthesia,
CKCS
underwent a CT scan (to assess the middle ear), BAER testing, and
MRI (to assess the grade of CM). Results: No
CKCS
had CM0. Nine (45%)
CKCS
had CM1; 11 (55%) had CM2.
All had at least 1 morphologic abnormality in waveforms. Absolute
and interpeak latencies were reported for all
CKCS
and compared between CM grades. The median threshold for
CKCS
with CM1 was 39 and for CM2 was 46. Absolute latencies
for
CKCS
with CM2 were consistently longer than
those for
CKCS
with CM1 with the exception of waves
II and V at 33 dB. Significant differences were found for wave V at
102 dB ( P = .04) and wave II at 74 dB (P = .008). Interpeak latency
comparisons were inconsistent between CM1 and CM2. Clinical
Relevance: Breed-specific BAER data for
CKCS
with
CM1 and CM2 were established. The results suggest that CM impacts
BAER latency results, but the influence of the malformation is not
always statistically significant or predictable. ... Our study
established breed-specific data of BAER measures for
CKCS
with CM1 and CM2. Specifically, we now have BAER data of absolute and
interpeak latencies, as well as the threshold in
CKCS
based
on CM grade. In addition, wave V latency intensity function was constructed
with respect to CM grade that can be utilized to assess the presence and
type of hearing loss in the
CKCS
. ... In conclusion,
BAER data in
CKCS
with respect to CM grade have
been established. BAER indexes differed based on CM grade in
CKCS
, but the influence of the grade of the malformation,
be it CM1 or CM2, is not always statistically significant or
predictable.
Reduced cingulate gyrus volume in
Cavalier-King-Charles-spaniels
with syringomyelia and
neuropathic pain revealed by voxel-based morphometry - a pilot study
Bjorn Nitzsche1, Sabine Schulze, Johannes Boltze, Martin J. Schmidt.
Front. Neuroanat. July 2023; doi: 10.3389/fnana.2023.1175953. Quote:
Objective: Pathomorphological alterations of the central nervous
system in dogs such as syringomyelia and Chiari-like malformation
can cause cranial and cervical hyperesthesia and neuropathic pain.
Long term activity of the pain network can induce functional
alteration and eventually even morphological changes in the pain
network. This may happen especially in the prefrontal- and cingulate
cortex where atrophy of the gray matter (GM) was observed in humans
with chronic pain, irrespective of the nature of the pain syndrome.
We tested the hypothesis that
Cavalier King Charles Spaniels
(CKCS)
with Chiari-like-malformation and associated
syringomyelia (SM) and pain show cerebral morphological differences
compared to animals without signs of syringomyelia and pain.
Methods: Volumetric datasets of 28 different brain structures were
analyzed in a retrospective manner, including voxel-based
morphometry, in magnetic resonance imaging data obtained from 41
dogs. Results: Volumetric analyses revealed a decrease of GM volumes
in the cingulate gyrus (CG) in
CKCS
with SM and
chronic pain when normalized to brain volume. This finding was
supported by voxel-based morphometry which showed a cluster of
significance within the CG. Conclusion: GM atrophy in the CG is
associated with chronic pain and thus may serve as an objective
readout parameter for the diagnosis or treatment of canine pain
syndromes.
Tolerability of long-term cannabidiol supplementation to healthy
adult dogs
. Isabella Corsato Alvarenga, Kim M. Wilson,
Stephanie McGrath. J. Vet. Intern. Med. November 2023; doi:
10.1111/jvim.16949. Quote: Background: Cannabidiol (CBD) has
therapeutic potential in companion animals. Shorter-term studies
have determined that CBD is well tolerated in dogs with mild adverse
effects and an increase in alkaline phosphatase (ALP) activity.
There is need to assess CBD's long-term tolerability. Hypothesis:
Determine the long-term tolerability of CBD administered PO to
healthy dogs for 36 weeks at dosages of 5 and 10 mg/kg body weight
(BW)/day. Our hypothesis was that CBD would be well tolerated by
dogs. Methods: Eighteen healthy adult beagle dogs were randomly
assigned to 3 groups of 6 each that received 0, 5, or 10 mg/kg
BW/day CBD PO. Dogs were adapted to their housing for 3 weeks and
received treatment for 36 weeks once daily with food. Adverse events
(AEs) were recorded daily. Blood biochemistry profiles were
monitored every 4 weeks. Data were analyzed as repeated measures
over time using a mixed model, with significance at a = 0.05.
Results: The 0 and 5 mg/kg treatment groups had similar fecal
scores, and the 10 mg/kg treatment group had higher frequency of
soft feces. No other significant AEs were noted. An increase (P <
.0001) in ALP activity occurred in groups that received CBD.
Remaining blood variables were within reference range. Conclusions
and Clinical Importance: Chronic administration of CBD in healthy
dogs at 5 mg/kg was better tolerated than 10 mg/kg, and both dosages
caused an increase in ALP activity. Although our data does not
indicate hepatic damage, it is recommended to monitor liver function
in dogs receiving CBD chronically.
Phenotypic characterization of Pomeranians with or without
Chiari-like malformation and syringomyelia
. Koen M.
Santifort, Ines Carrera, Kenny Bossens, Paul J. J. Mandigers. Front.
Vet. Sci. December 2023; doi: 10.3389/fvets.2023.1320942. Quote:
Introduction: Chiari-like malformation (CM) and syringomyelia (SM)
are frequently diagnosed conditions in small and toy dog breeds,
such as the
Cavalier King Charles Spani
el and
Griffon Bruxellois. CM/SM is only rarely reported in Pomeranians in
literature to date. The aims of this study are to 1/describe the
phenotype of Pomeranians with or without CM/SM and 2/evaluate for
differences and associations between CM/SM and owner-reported
clinical signs (ORCS) or signalment factors. Materials and methods:
From February 2015 to June 2023, historical data and signalment
(including country of origin, pedigree, sex and neuter status, age,
and body weight) and ORCS of Pomeranians were recorded at multiple
institutions. MRI studies of all dogs were evaluated for
classification of CM/SM. Additionally, quantitative measurements
were performed for SM. Results: A total of 796 dogs from 22
different countries were included. Total prevalence of CM was 54.9%
(437/796) and the prevalence of SM was 23.9% (190/796). The top 5
ORCS included 1/scratching with skin contact, rubbing head or ears,
or both (57.6% of dogs with ORCS), 2/air licking (30.7% of dogs with
ORCS), 3/spontaneous signs of pain (26.0% of dogs with ORCS),
4/persistent licking front and/or hind paws (22.6% of dogs with
ORCS), 5/phantom scratching (22.6% of dogs with ORCS). Phantom
scratching, vocalization, head shaking, spontaneous signs of pain,
and air licking were associated with having SM. There were no
statistically significant associations between quantitative syrinx
measurements and ORCS. There were statistically significant
associations between CM classification and 1/country of origin,
2/having a pedigree, and 3/age. There were statistically significant
associations between SM classification and 1/age and 2/body weight.
Discussion: This is the first large study evaluating CM/SM in the
Pomeranian dog breed. Veterinary clinicians can use these findings
to increase the likelihood of correctly determining the presence or
absence of CM/SM in Pomeranians. Breeders may consider using the
information regarding signalment factors as well as ORCS associated
with CM/SM classifications to select dogs for screening procedures.
But an MRI-based diagnosis is needed to properly ascertain the exact
CM/SM status of their breeding stock until a fool-proof
characteristic or genetic marker is found.
RETURN TO TOP
2024
The effect of MRI-based screening and selection on the prevalence of
syringomyelia in the Dutch and Danish
Cavalier King Charles
Spaniels
. Citlalli Limpens, Vivian T. Smits, Hille
Fieten, Paul Mandigers. Front. Vet. Sci. January 2024; doi:
10.3389/fvets.2024.1326621. Quote: Introduction: Syringomyelia (SM)
is a heritable disorder causing a fluid filled cavity (FFC) in the
spinal cord with a reported overall prevalence in the
Cavalier King Charles Spaniels (CKCS)
of 39 to 46%.
Breeders started screening their
CKCS
with MRI in the Netherlands
since 2004 and in Denmark since 2015. The goal of this study was to
evaluate the effect of MRI-based selection in breeding on the
prevalence of SM. Method: MRI scans of 2125 purebred
CKCS
were available. SM was defined as having a visible FFC in the spinal
cord. Prevalence of SM per year of birth was calculated and a
logistic regression was used to evaluate affected status of
offspring from affected versus unaffected parents and age category
of the parent. And to study the combined effect of parental status
and age-category to evaluate the effect on affected status of the
offspring. Results: The mean FFC in affected
CKCS
was 2.03 ± 1.47 mm and ranged from 0.5 to 9 mm (median of 1.5 mm).
An age effect exists as older
CKCS
have a higher
frequency of being affected compared to younger
CKCS
There was no significant sex predilection for SM in this dataset.
The mean prevalence of SM decreased slightly from 38% (2010-2014;
2.8 ± 1.3 years of age (mean ± sd); median 2.6 years) to 27%
(2015-2019; 2.4 ± 1.2 years of age; median 2.1 years) in the
screened population of
CKCS
(p= 4.3e-07). Breeding
with 2 affected parents increased the Odds ratio for producing
affected offspring with 3,08 (95% CI 1.58-6.04) compared to breeding
with unaffected parents. Discussion: MRI-based screening and
selection against SM led to a minimal decrease in prevalence of SM
in the Dutch and Danish
CKCS
population. Breeding
with dogs with SM significantly increases the risk of affected
offspring. As the disorder is progressive with age, and based on the
results of this study, MRI-based screening for all
CKCS
is recommended at an age of 3 years or older, and to reduce SM more
effectively,
CKCS
affected with SM should not be
used for breeding.
Clinical predictors of syringomyelia in
Cavalier King
Charles Spaniels
with chiari-like malformation based on
owners' observations
. Tenna Remler Pedersen, Maiken Bayer
Thode Bach, Camilla Løkke Stougaard, Hanne Gredal, Clare Rusbridge,
Nanna Brix Finnerup, Mette Berendt. Acta Vet. Scandin. February
2024; doi: 10.1186/s13028-024-00725-1. Quote: Background:
Syringomyelia (SM) is a prevalent inherited developmental condition
in
Cavalier King Charles Spaniels (CKCSs)
with
Chiari-like malformation (CM), accompanied by a variety of clinical
manifestations, including signs of neuropathic pain. Magnetic
resonance imaging (MRI) is the gold standard in SM diagnosis.
However, it is desirable to establish clinical predictors that can
identify
CKCSs
with a large clinical syrinx that
needs treatment, as some owners cannot afford or lack access to MRI.
The aims of the study were to investigate owner-reported clinical
signs of SM and clinical predictors of a large clinical syrinx,
using predictive values of significant signs, individually and in
combinations. Eighty-nine
CKCSs
participated in
this retrospective study. Based on MRI diagnosis, dogs were
distributed into three groups: CM without syrinx or with a maximum
transverse width < 2 mm (n = 13), CM with small syrinx 2.00-3.99 mm
(n = 26) and CM with large syrinx >4 mm (n = 50). A structured
investigator-owner interview using a standardized questionnaire was
used to collect data regarding clinical signs of CM and SM. The
statistical tests Pearson's chi-square, Fisher's Exact and
Spearman's rank order were used to assess the difference in
owner-reported signs between groups. For signs with significant
differences, positive and negative predictive values (PPV and NPV)
were calculated. Results: Following clinical signs were reported
significantly more frequent in dogs with a large syrinx: phantom
scratching, bilateral scratching of the neck or shoulder, aversion
when that area is touched, or exacerbation of clinical signs when
the dog is emotionally aroused. Each individual sign had a high PPV,
indicative of a large clinical syrinx. The PPV increased further
when the signs phantom scratching, aversion to touch to the head,
neck or shoulder, and a preferred head posture during sleep were
present in combination. Conclusions: Specific clinical signs can be
used individually and in combination as clinical predictors of a
large clinical syrinx in
CKCSs
with CM and SM.
General practitioners can utilize this information to identify
CKCSs
with a large syrinx to initiate necessary
treatment. This is particularly useful in cases where access to or
affordability of an MRI diagnosis is limited.
Relationship between syringomyelia and myxomatous mitral valve
disease in
Cavalier King Charles spaniels
Maiken B. T. Bach, Camilla L. Stougaard, Maria S. Thøfner, Maria J.
Reimann, Ulrik Westrup, Jørgen Koch, Merete Fredholm, Torben
Martinussen, Mette Berendt, Lisbeth H. Olsen. J. Vet. Intern. Med.
February 2024; doi: 10.1111/jvim.17018. Quote: Background:
Syringomyelia (SM) and myxomatous mitral valve disease (MMVD) are
highly prevalent in
Cavalier King Charles spaniels (CKCS)
Cardiac status in
CKCS
with and without SM is
currently unknown. Objectives: To investigate the association
between SM and MMVD severity in
CKCS
and
CKCS
with SM with and without clinical signs of SM.
Animals: . ... The study cohort consisted of 55
CKCS
40
CKCS
with SM and 15
CKCS
without SM that had Magnetic Resonance Imaging (MRI) at the
University [of Copenhagen, Denmark] Hospital for Companion Animals,
Department of Veterinary Clinical Sciences in 2007-2015. ... Over
the years, national breeding schemes have been established to reduce
the occurrence of MMVD in
CKCS
, reducing the
prevalence of early onset heart murmur in
CKCS
. At
the same time, however, no such breeding restrictions have been
established to remove
CKCS
with early-onset SM from
the breeding program, thereby reducing the incidence of SM. The
concern that longstanding MMVD-breeding restrictions could
potentially influence the prevalence of SM, motivated the present
study. Therefore, this study aimed to investigate MMVD in
CKCS
with and without SM. The secondary aim of this study
was to investigate the severity of MMVD in SM affected
CKCS
with and without clinical signs of SM. ... Methods: A
combined retrospective and prospective study. MRI and
echocardiography were used to diagnose SM and MMVD, respectively.
The association between SM and MMVD severity (left ventricle
internal diameter in diastole normalized to bodyweight [LVIDDN] and
left atrium to aortic ratio [LA/Ao]) were tested using multivariable
linear regression analysis adjusting for sex and age. ... Based on
American College of Veterinary Internal Medicine (ACVIM) consensus
statement guidelines, the severity of MMVD was staged as follows:
Group A,
CKCS
with no auscultatory heart murmur and
normal echocardiogram (no or minimal MR [MR<20%]); group B1,
CKCS
with an auscultatory heart murmur or MR >20% and
echocardiographic evidence of MMVD but no cardiac enlargement
(LA/Ao<1.6 and LVIDDN<1.7); group B2,
CKCS
with
heart murmur >3 of 6 and current or previous echocardiographic
evidence of cardiac enlargement (LA/Ao>1.6 and LVIDDN>1.7), but
without current or previous clinical signs of CHF; group C,
CKCS
with CHF. Congestive heart failure was defined as a
history of MMVD, clinical signs of CHF (eg, cough, dyspnea,
tachypnea, nocturnal restlessness, and exercise intolerance),
echocardiographic changes compatible with CHF caused by MMVD and
response to diuretic treatment. ... In total, 32 of the 55
CKCS
were diagnosed with ACVIM MMVD stage B1, 7 with stage
B2 and 3 dogs with stage C. ... Results: Overall, no significant
difference in LVIDDN and LA/Ao was found between
CKCS
with or without SM. However,
CKCS
with symptomatic
SM had significantly smaller LVIDDN (1.45 [1.30-1.50]) (median
[IQR]) and LA/Ao (1.20 [1.10-1.28]) compared to
CKCS
with asymptomatic SM (1.60 [1.50-1.90] and 1.40 [1.20-1.75]) as well
as CKCS without SM (0.24 [0.03-0.45] and 0.30 [0.05-0.56]) (all P
values <.03). Conclusions and Clinical Importance: ... This study
investigates the co-occurrence of SM and MMVD. We found no overall
association between SM (symptomatic and asymptomatic pooled
together) and the severity of MMVD in
CKCS
, but
CKCS
with symptomatic SM exhibited smaller left
ventricular and left atrial dimensions compared to those with
asymptomatic SM and
CKCS
without SM, suggesting
that a complex relationship might exist. However, this study was
limited by a relatively small and selected study sample.
Cerebrospinal Fluid Concentrations of Calcitonin Gene Related
Peptide in Dogs with Chiari-Like Malformation
. John Macri;
Natasha Olby; Courtney Whicker. ACVIM Forum 2024. June 2024. Quote:
Background:
Cavalier King Charles Spaniels (CKCS)
have a high prevalence of Chiari-like malformation and syringomyelia
(CMSM). Dogs with CMSM display signs of neuropathic pain and itch.
Imaging findings often do not correlate with severity of signs.
Neuropeptides including calcitonin gene related peptide (CGRP) have
been implicated in neuropathic pain. Hypothesis: Cerebrospinal fluid
(CSF) concentrations of CGRP (C-CGRP) will correlate with CMSM
clinical sign severity. Animals:S Twenty-nine
CKCS
Methods:
CKCS
underwent pain and itch
quantification by owners (questionnaires) and investigators
(physical examination), a brain and cervical spine MRI, and lumbar
CSF collection. CSF was frozen to -80°F. C-CGRP in CSF were measured
using an ELISA assay (MyBiosource, San Diego, CA). Dogs were grouped
by presence of syrinx, pain, and itch, and C-CGRP were compared
between groups using Wilcoxon Rank Sum; C-CGRP and owner reported
pain score were evaluated using linear regression analysis. Results:
15/29
CKCS
had SM on MRI, 13/29 were painful, and
12/29 were scratching. C-CGRP was significantly higher in painful
dogs (median 114.3, range 11.6-238.3 pg/ml) and dogs with itch
(111.67, 38.5-234.8 pg/ml) compared to non-painful dogs (72.57pg/ml,
0-266.2 pg/ml) (p=0.025) and dogs without itch (79.7, 0-266.2
pg/ml). There was a significant correlation between owner pain score
and C-CGRP (R2=18%, p=0.033). No significant difference in C-CGRP
was noted between SM+ (99, 0-226.6 pg/ml) and SM- (102.2, 5.9-266.2
pg/ml) dogs (p=0.25). Cconclusions: CSF CGRP concentration is
elevated in
CKCS
exhibiting pain and itch. CGRP may
contribute to neuropathic pain in CMSM and could be a target for
therapeutic intervention.
A Novel Multiple Camera RGB-D Calibration Approach Using Simulated
Annealing
. Mehran Taghipour-Gorjikolaie, Marco Volino,
Clare Rusbridge, Kevin Wells. IEEE Access. July 2024; doi:
10.1109/ACCESS.2024.3424412. Quote: The development of a
cost-effective surface scanning system tailored for live animal
image capture can play an important role in biomedical research. The
primary aim was to introduce a low-cost system, achieving a surface
reconstruction error of less than 2mm, and enabling rapid
acquisition speeds of approximately 1 second for a complete
360-degree surface capture. ... The main goal of the project is to
produce 3D surface models of live dog heads (without sedation or
another immobilization). ... Leveraging a five RGB-D camera
configuration, our approach offers a simple, low-cost alternative to
conventional lab-based 3D scanning setups. Key to our methodology is
a novel calibration strategy aimed at refining intrinsic and
extrinsic camera parameters simultaneously for improved accuracy. We
introduce a novel 3D calibration object, extending existing
techniques employing ArUco markers, and implement a depth correction
matrix to enhance depth accuracy. By utilizing Simulated Annealing
optimization alongside our custom calibration object, we achieve
superior results compared to conventional optimization techniques.
Our obtained results show that the proposed depth correction method
can reduce the reprojection error from 3.12 to 2.89 pixels.
Furthermore, despite the simplicity of our reconstruction method, we
observe around a 22% improvement in surface reconstruction compared
to factory calibration parameters. Our findings underscore the
practicality and efficacy of our proposed system, paving the way for
enhanced 3D surface reconstruction for real-world surface capture.
... Using a simple, low-cost, 3D-surface scanning and reconstruction
system based on five RGB-D sensors combined with a dedicated
calibration scheme can provide useful surface capture for dogs at
risk of breeding disorders manifest in their physical head
presentation. Such an approach may be a useful adjunct or triage
approach prior to MRI and CT based investigation. We were successful
in obtaining data for our study on CKCS head morphology supporting
our claim. Moreover, our future work is to make the 3D
reconstruction step currently relies on manual intervention, which
we aim to automate. This can be achieved by employing surface-based
features to identify common boundaries, thereby removing outliers
and refining the final 3D image automatically.
Incidence of Chiari-like Malformation/Syringomyelia in a Cohort of
Small Dog Breeds Scanned Using MRI over a Period of 8 Years in the
Netherlands
. Fredrik Hoholm, Karin Bruining-Staal, Paul
J.J. Mandigers. Pets. October 2024; doi.org/10.3390/pets1030019.
Quote: Background: Chiari-like malformation (CM), Syringomyelia (SM)
and middle ear effusion (MEE) are frequently observed disorders in
Cavalier King Charles Spaniels (CKCSs), Pomeranians, and less
frequently the Griffon. There are a few reports in which small dogs
have been identified as suffering from CM/SM. Methods: From all MRI
centers based in the Netherlands, MRI scans for small dog breeds
performed for various reasons over a period of 8 years were
collected. Scans that enabled a CM and/or SM evaluation were
included and evaluated. Results: In total, 177 MRI scans were
included. CM could be evaluated in 163 out of 177 dogs. In 63 dogs,
no CM was observed, while 100 dogs had CM. SM could be evaluated in
144 out of 177 dogs. No SM was seen in 56 dogs and SM was seen in 88
dogs. Both CM and SM were seen in high frequency in the Chihuahua,
French Bulldog, Griffon, and Pug but did also occur in lower
frequencies in various other small breed dogs and crosses. CM and/or
SM does occur in various other small dog breeds and crosses
suggesting that it is indeed a type-related disorders. As it can
cause serious clinical signs breeders should be aware of the risk of
CM/SM when breeding with these small dog breeds.
RETURN TO TOP
2025
A data driven approach for soft tissue biomarker identification
linked to Chiari-like malformation and syringomyelia
. Jake
Cumber, Emma Scales-Theobald1, Clare Rusbridge, Kevin Wells. Front.
Vet. Sci. January 2025; doi: 10.3389/fvets.2024.1492259. Quote:
Canine Chiari-like malformation (CM) is a neuroanatomical condition
associated with conformational change of the cranium, craniocervical
junction and neuroparenchyma, resulting in pain (Chiari associated
pain or CM-P) and the development of syringomyelia (SM). The
associated neuro-disability in affected individuals compromises
quality of life. CM is characterized by overcrowding of the brain
and cervical spinal cord and is predisposed by skull-base shortening
and miniaturization with brachycephalic toy dogs overwhelmingly
represented. Magnetic resonance imaging (MRI) is conventionally used
for diagnosis; however, CM is complex and ubiquitous in some dog
breeds so that diagnosis of CM-P relies on a combination of clinical
signs, MRI, and elimination of other causes of pain. This research
aimed to identify cranial and spinal pathologies and neural
morphologies linked to CM-P and SM in dogs using MRI scans and
machine learning with the aim of identifying novel data driven
biomarkers which could confirm CM-P and identify dogs at risk of
developing SM. ... Midsagittal T2 weighted MRI slices of one-hundred
and twenty
Cavalier King Charles spaniels (CKCS) dogs
were provided from one veterinary practice, and included 63 males
and 57 females, ranging from 1.3 to 9.7 years. ... The methodology
identified four regions of interest as having robust discrimination
for CM-P, with 89% sensitivity and 76% specificity. A set of
morphological features linked to CM-P were identified. ...
Surprisingly, all four predictive regions were outside the brain and
three were outside nervous system, these ROI's being (1) the caudal
end of the soft palate (AUC = 0.70), (2) larynx and the soft tissue
directly dorsal the larynx (AUC = 0.73), and (3) the fascia
containing the carotid artery caudal to the bifurcation and ventral
to caudal C2 (AUC = 0.81). Additionally, there was a region (4) at
the level of the C3 spinal cord segment (spinal cord associated with
the caudal third of the C2 vertebral body) (AUC = 0.64). ... Four
regions of interest were also identified as having robust
discrimination for SM, with 84% sensitivity and 80% specificity. ...
Two of these regions were located within the brain being (1) the
rostral cerebellum and tentorium cerebelli region (AUC = 0.77) and
(2) brain stem immediately ventral to the fourth ventricle (AUC =
0.78). There were two regions outside the nervous system being (3)
rostral to the soft palate ROI found in the CM-P study (AUC = 0.74)
and (4) the epiglottal region of the larynx (AUC = 0.71), as
summarized in Figure 10A. ... Overall, these findings shed light on
the distinct morphologies related to CM-P and SM, offering the
potential for more accurate and objective diagnoses in affected dogs
using MRI. These results contribute to the further understanding of
the complex pathologies associated with CM and SM in brachycephalic
toy pure and mixed breed dogs and support the potential utility of
data-driven techniques for advancing our knowledge of these
debilitating conditions.
Cerebrospinal Fluid Concentrations of Calcitonin Gene Related
Peptide in Dogs With Chiari-Like Malformation
John D.
Macri, Courtney Sparks, Zachary Anderson, Natasha Olby. J. Vete.
Intern. Med. May 2025; doi: 10.1111/jvim.70105. Quote: Background:
The biomarker Calcitonin Gene-Related Peptide (CGRP) is elevated in
human conditions associated with neuropathic pain, but has not yet
been studied in
Cavalier King Charles Spaniels (CKCS)
with Chiari-like malformation (CM). ... Calcitonin Gene-Related
Peptide (CGRP) is a neuromodulator for central sensitization and
nociceptive signaling of pain expressed in both the CNS and
peripheral NS (PNS) [8]. It plays an important role in the
regulation of the trigeminovascular system that is central to
migraine pathophysiology. The discovery that serum CGRP
concentration is elevated in human migraine patients led to the
effective treatment of migraine with CGRP inhibitors. The most
common and clinically debilitating symptom in people with Chiari
malformation is headache. There are several headache subtypes in
this disorder, one of which is migraine. The etiology of these
headaches is complex and includes altered intracranial pressure
(leading to the typical Valsalva headache associated with coughing)
and CSF flow as well as trigeminal nerve involvement. The role of
CGRP is not reported in human Chiari malformation. ...
Hypothesis/Objectives:
Cavalier King Charles Spaniels
with clinical signs of CMSM would have higher CSF
concentrations of CGRP than asymptomatic
CKCS
. Our
aim was to measure CSF CGRP concentrations in
CKCS
with and without clinical signs of CMSM. Animals: Twenty-nine
CKCS
drawn from research and clinical cases
underwent quantification of pain and scratching, a brain and spinal
cord MRI, and lumbar CSF collection. Methods: This was a prospective
study with both normal and clinically affected
CKCS
recruited. The CSF concentration of CGRP (C-CGRP) was measured using
an ELISA assay. Dogs were grouped by the presence of SM, pain, and
scratching, and concentrations of C-CGRP were compared between
groups using Wilcoxon Rank Sum. The concentration of C-CGRP, pain
score, and SM diameter were evaluated using linear regression.
Results: Concentration of C-CGRP was significantly higher in painful
dogs (median 116.1, range: 11.6-238.3 pg/mL) as compared to
non-painful dogs (median 77.7 pg/mL, range 0-266.2 pg/mL;
p = 0.0124). No significant difference in C-CGRP concentration was
noted between dogs with (median 99.3, range 0-226.6 pg/mL) and
without (median 102.2, range 6.0-266.2 pg/mL) SM (p = 0.305). ... In
our cohort of
CKCS
, C-CGRP was not significantly
associated with syringomyelia but was significantly associated with
the presence of pain. While elevated in painful dogs, there was
overlap in the range of concentrations of C-CGRP between groups and
our data do not suggest that C-CGRP concentration could be used as a
discriminating biomarker of neuropathic pain in individual cases.
Rather, our results support the possibility that elevated CGRP
concentrations are playing a role in the development of clinical
signs of CMSM in
CKCS
and could represent a novel
therapeutic target. ... Regardless of whether CGRP causes migraines
in
CKCS
with CM, the increased concentration of
C-CGRP in painful dogs suggests it might have a role in the
pathophysiology of pain in these dogs and present a therapeutic
target. New migraine treatments in humans include CGRP receptor
antagonists as well as monoclonal antibodies that target CGRP or its
receptors. Ubrogepant has been tested and noted to have low receptor
affinity in dogs compared to humans, but the affinity,
bioavailability, safety, and efficacy of other CGRP inhibitors in
dogs such as Atogepant, Rimegepant, and Zavegepant is unknown. ...
Conclusions and Clinical Importance: Cerebrospinal fluid CGRP
concentration is elevated in
CKCS
exhibiting pain
regardless of the presence of SM. CGRP might contribute to
neuropathic pain in CMSM and could be a target for therapeutic
intervention.
Genomic analyses in
Cavalier King Charles spaniels
identify loci associated with clinical signs of Chiari-like
malformation and Syringomyelia
. Courtney R. Sparks, Jonah
N. Cullen, Michael W. Vandewege, Meghan Leber, Katie M. Minor,
Steven G. Friedenberg, Natasha J. Olby. BMC Vet Res. May 2025; doi:
10.1186/s12917-025-04754-4. Quote: Background: Chiari-like
malformations (CM) and syringomyelia (SM) are common in
Cavalier King Charles spaniels (CKCS)
leading to variable
manifestations of pain and scratch. Inheritance studies suggest a
polygenic mode of inheritance and association studies have
identified loci associated with the presence of SM on MRI. Given the
poor correlation of clinical signs of CMSM with MRI findings, we
hypothesized that an association study with clinical signs as the
phenotype could reveal new loci of interest. The objectives of this
study were to perform genome-wide association studies on CKCS using
SM and clinical sign phenotypes of pain and scratch and to use whole
genome sequencing (WGS) to identify variants in regions of interest.
We collected DNA on 174
CKCS
. Owners completed
questionnaires to establish the clinical pain and scratch phenotype
and magnetic resonance imaging (MRI) was used to identify CM and SM
(linear T2 hyperintensity greater than 2 mm in height) in all dogs.
Dogs were genotyped using the Axiom K9 HD (710,000 snps) array. GWAS
analyses were performed using GEMMA and categorical and quantitative
approaches were used to define clinical phenotypes. Whole genome
sequencing (WGS) was performed on an Illumina HiSeq 4000
high-throughput sequencing system. Results: There were no regions
associated with SM presence. The presence of signs of pain and
scratch was associated with a region on Canis familiaris autosome
(CFA) 26 downstream of ZWINT, previously associated with skull
changes in
CKCS
with SM, although genome-wide
significance was not reached. Loci were also associated with
quantitative pain and scratch scores on CFA 13, 2 and 38. There were
66 variants that segregated with phenotype including 2 missense
variants that were predicted to have moderate effects on ZWINT
function. Conclusions: ... The CMSM condition in dogs is complex and
most likely polygenic. There are likely several genes that are
involved in the clinical manifestation of CMSM in dogs. The
replication of the locus in the region of ZWINT between a study
using skull morphometry and our study using clinical phenotype adds
to the evidence that this region is important in clinical CMSM in
CKCS
. More work is required to investigate the
genomic regions of interest identified in this study. ... To
summarize, we collected DNA, MRIs, and detailed information on
clinical signs in a large cohort of
CKCS
. We found
that by differentiating dogs on the basis of clinical signs, rather
than the presence of SM, we were able to detect several regions of
interest including snps that replicated previously published
findings that used a morphological measure of phenotype rather than
a functional one. We used categorical and continuous measures of
clinical signs to classify phenotypes and found snps on CFA 2, 13,
26, and 38. Within these regions, we identified 2 moderate impact
mutations affecting the ZWINT gene. Further work is warranted to
determine the segregation of these regions and genes with disease in
dogs with CMSM. ... The identification of a locus on CFA26 using the
clinical phenotype of pain and scratch that coincided with a locus
identified in a morphological study provides strong support for this
as a region of interest.
Questionnaire-Based Study of the Correlation Between Sleep and Pain
in
Cavalier King Charles Spaniels
. Rell
Parker, llie Sherman, Mindy Quigley, John Rossmeisl, Stephen Werre.
Abstract, 2025 ACVIM Forum. June 2025. Quote: Background: The correlation
between sleep and chronic pain in dogs is poorly understood. In
people, poor sleep is correlated with chronic pain. It has
previously been reported that
cavalier King Charles spaniels
(CKCS)
with caudal occipital malformation may have sleep
disturbances. Hypothesis/Objectives: We hypothesized that
CKCS
with neuropathic pain (NeP) would have an increased
sleep and nighttime restlessness evaluation score (SNoRE3.0) and a
worse quality of life (QOL). Animals: 68
CKCS
dogs.
Methods: Owners of
CKCS
were recruited to complete
a REDCap survey that was available on the institutional website. It
collected demographic information, the SNoRE3.0 sleep survey, and an
NeP neuropathic pain questionnaire including a QOL score. Results:
The average age of CKCS was 5.0 years. There were 23 male castrated,
23 female spayed, 13 male intact, and 9 female intact dogs. The
median SNoRE3.0 score was 12 (range 0 to 35). The median NeP score
was 0.83 (range 0 to 2.6). The median QOL score was 2 (range 1 to
5). The Spearman correlation coefficient between the SNoRE3.0 and
NeP was 0.381, with p=0.0012. The Spearman correlation coefficient
between SNoRE3.0 and QOL was 0.29, with p=0.014. The Spearman
correlation coefficient between NeP and QOL was 0.58, with p<0.0001.
Conclusions and Clinical Importance: These data indicate there is a
positive correlation between owner survey responses regarding
increased nighttime restlessness, presence of neuropathic pain, and
worse QOL. This indicates that sleep may be an important component
of neuropathic pain in
CKCS
Owner-Observed Sleep Disturbances Between
Cavalier King
Charles Spaniels
With and Without Symptomatic Chiari-Like
Malformation
. Amanda Valentino, Natasha Olby. Abstract N10,
2025 ACVIM Forum. June 2025. Quote: Background: Chiari-like malformation (CM)
and syringomyelia (SM) are prevalent among
Cavalier King
Charles Spaniels (CKCS)
. Sleep disturbances are common in
people with this malformation; however, no studies have investigated
whether symptomatic
CKCS
experience these.
Hypothesis/Objectives: We hypothesized that
CKCS
with symptomatic CM±SM exhibit sleep disturbances. Animals:
Thirty-nine
CKCS
with and without symptomatic CM±SM
were included. All dogs slept in the same room as their owners.
Methods: Questionnaire-based study conducted using 2 validated
questionnaires: CHASE for severity of CM±SM signs, and SNoRE 3.0 for
evaluation of sleep disturbances. Dogs with a CHASE score of 7 or
greater were classified symptomatic for CM±SM. SNoRE 3.0 scores were
compared between symptomatic and asymptomatic dogs using the
Wilcoxon rank sum test. Results: There were 19 symptomatic dogs aged
3-10 years (8 males, 11 females), and 20 asymptomatic dogs aged 1-10
years (8 males, 12 females). The mean CHASE score for symptomatic
dogs was 12.32 (median: 13.0, range: 7-18) and asymptomatic dogs was
1.85 (median: 1, range: 0-6). The total SNoRE score for symptomatic
dogs had a median of 10 (range: 6-30), while asymptomatic dogs had a
median of 6 (range: 6-23). Significant differences were found
between the groups comparing total SNoRE score, sleep quality, and
sleep interruptions (p=0.0016, 0.0052, and 0.0009, respectively).
Conclusions and Clinical Importance:
CKCS
with
symptomatic CM±SM exhibit owner-reported signs of sleep
disturbances. Confirmation using polysomnography is warranted and
sleep should be considered in the therapeutic plan.
Chiari-like Malformation and Syringomyelia in Pomeranians: A
Longitudinal Study
. Mees R. Jansma, Marieke van den Heuvel,
Kenny Bossens, Erik Noorman, Michelle Hermans, Paul J. J. Mandigers.
Vet. Sci. July 2025; doi: 10.3390/vetsci12070677. Quote: Background:
Chiari-like malformation (CM) and syringomyelia (SM) are commonly
observed conditions in Pomeranian dogs. Affected dogs may develop
clinical signs that significantly impact quality of life. Therefore,
it is crucial to select only unaffected dogs for breeding. However,
the progression of CM/SM has not been fully elucidated. Dogs that
are unaffected or mildly affected may progress to severe SM over
time. The primary aim of this study is to investigate the
progression of CM/SM through repeated MRI scans. A secondary
objective is to evaluate the effect of furosemide treatment on
syrinx sizes, given its frequent prescription. Methods: Pomeranians
that underwent two CM/SM screenings between 2015 and 2025 were
included. CM/SM classifications were assessed, and quantitative
syrinx measurements were conducted. Maximum syrinx diameter (MSD)
and maximum syrinx-to-spinal cord diameter ratio (MSD/SCD-r) were
measured and documented. Dogs were classified based on the
progression of SM. ... The first and second MRI are referred to as
MRI1 and MRI2, respectively. For both scans, each dog was assessed
for CM/SM classification, and quantitative measurements of SM were
performed. ... Furosemide treatment was documented, and its effect
on syrinx size was compared with that in dogs not receiving
furosemide. ... Results: At the time of the second MRI, 39.6% of
dogs either developed SM or showed substantial progression, whereas
12.5% demonstrated partial recovery. Of the dogs initially
classified as free from SM, 20.7% had developed the condition. A
significant increase was observed in both MSD (p = 0.0058) and
MSD/SCD-r (p = 0.0038) between MRI1 and MRI2. Notably, the change in
MSD between MRI1 and MRI2 was statistically significantly smaller in
dogs treated with furosemide compared to untreated dogs (p = 0.030).
Conclusions: These findings indicate that syrinx dimensions are
dynamic and may fluctuate over time, although a general trend toward
progression is observed. Furthermore, furosemide may mitigate the
progression of SM.
Syringomyelia in Australian
Cavalier King Charles spaniels
prevalence and changes over 16 years of magnetic resonance imaging
screening
. L McLeay, G Child. Austr. Vet. J. September
2025; doi: 10.1111/avj.70013. Quote: Syringomyelia is a common and
heritable disorder in
Cavalier King Charles Spaniels (CKCS)
characterised by fluid accumulation within the spinal cord that may
result in pain and neurological dysfunction. The prevalence of
syringomyelia in
CKCS
in Australia has not
previously been reported. The goal of this study was to assess the
prevalence and severity of syringomyelia in magnetic resonance
imaging (MRI)-screened breeding
CKCS
in New South
Wales, Australia, from 2008 to 2024, and to evaluate changes over
time. A secondary goal was to investigate associations between age
and coat colour with the prevalence and severity of syringomyelia. A
retrospective observational study was conducted on 386
CKCS
undergoing voluntary MRI screening. The dogs included in the study
had no clinical signs of syringomyelia or Chiari-like malformation.
Syringomyelia was defined as fluid accumulation within the spinal
cord with a diameter > 1.0 mm. Dogs were graded by severity and
grouped by age, coat color and screening period. Statistical
analyses included Fisher's exact test, Wilcoxon rank-sum,
Kruskal-Wallis and multivariable logistic regression. Syringomyelia
was detected in 50.5% of dogs. No significant change in prevalence
or severity was observed over the 16-year period. Syringomyelia
prevalence increased with age (P < 0.001). Coat colour was
associated with both prevalence and severity, with black and tan
dogs more severely affected than Blenheim dogs (P = 0.007).
Syringomyelia was highly prevalent in Australian
CKCS
with no significant improvement over time despite voluntary
screening and breeding recommendations. Greater emphasis on MRI
screening beyond 3 years of age and stricter breeding practices may
be necessary to reduce disease prevalence and severity in the breed.
A Cardiac Cycle Resolved CFD Simulation of CSF Flow in a
CKCS
. Ryan Jones, Srdjan Cirovic, Clare Rusbridge.
2025 Surry Research  Symposium. Univ. of Surrey. October 2025.
Cavalier King Charles Spaniels (CKCS)
are highly
predisposed to Chiari-like malformation (~95%) and syringomyelia
(~45%)[1], conditions affecting cerebrospinal fluid (CSF)
circulation. These disorders cause pain and neurological
dysfunction, yet their underlying mechanisms remain unclear.
Understanding normal CSF dynamics is a critical first step in
treating these conditions. CSF flow is recognised as pulsatile and
cardiac-driven, shaped by craniospinal compliance. Phase-contrast
MRI can capture velocities at limited locations, but cannot resolve
pressures or 3D flow patterns. Computational Fluid Dynamics (CFD)
overcomes these limitations by reconstructing the entire flow field
from MRI-derived anatomy, enabling visualization of velocities,
pressures, and pressure gradients. Here, we present the first
cardiac cycle-resolved CFD simulation of CSF flow in a
CKCS
offering new insights into the CSF dynamics of a healthy dog. ...
Qualitative Results: • Jet-like flows observed, producing localised
high velocities • Flow appears disturbed but not turbulent •
Pressure-Velocity phase shifts indicate flow is driven by pressure •
Bidirectional pulsatile motion. Future Directions: • Simulate the
healthy flow in
CKCS
• Compare unaffected and
affected flow • Identify CM/SM biomarkers • Simulate surgical
intervention. In this work we present the first cardiac
cycle-resolved CFD simulation of cerebrospinal fluid flow in a
Cavalier King Charles Spaniel
. The simulations show
that Reynolds numbers never exceeded 30, confirming that the flow
remains firmly laminar. By contrast, human studies often report
higher Reynolds numbers, which help explain the more complex flow
patterns described clinically. The Womersley numbers were
consistently greater than one, indicating that CSF motion in the
CKCS
is pulsatile and inertia-driven, as expected
under cardiac cycle forcing. However, these values were
significantly lower than those reported in humans, suggesting that
the flow in dogs is less inertially dominated. Together, these
findings highlight important species-specific differences in CSF
dynamics. Most importantly, they demonstrate how CFD can provide
access to pressures and gradients that cannot be measured with MRI
alone, offering a new window into the mechanisms that may contribute
to Chiari-like malformation and syringomyelia.
Spatial transcriptomic alterations of the dorsal horn in dogs with
neuropathic pain
. Tenna Remler Pedersen, Jørgen Steen
Agerholm, Clare Rusbridge, Nanna Brix Finnerup, Fernando
Constantino-Casa, Merete Fredholm, Mette Berendt, Jens Randel
Nyengaard. Basic Sci. Pain Rpts. November 2025; doi:
10.1097/PR9.0000000000001360. Quote: Introduction: Microglia and
astrocytes are believed to play a central role in the pathogenesis
of neuropathic pain (NeP). These glial cells are commonly identified
by the expression of ionized calcium-binding adaptor molecule 1
(IBA1) for microglia and glial fibrillary acidic protein (GFAP) for
astrocytes. Under pathological conditions, astrocytes and microglia
undergo both morphological and transcriptional changes, which may
promote shifts in functions that can have both protective and
detrimental effects on the surrounding neuroparenchyma. Like humans,
the dog breed
Cavalier King Charles Spaniels (CKCSs)
suffers from heritable syringomyelia (SM) which in both species is
associated with NeP. Objectives: To investigate the potential role
of IBA1 and GFAP-positive cells in the dorsal horn in
CKCSs
with SM and NeP. Methods: Using NanoString GeoMx technology, we
conducted spatial transcriptomic analyses on spinal cord dorsal
horns from
CKCSs
with SM and NeP. Results: Several
differentially expressed genes were identified in dogs with SM and
NeP. Cells positive for IBA1 showed upregulation of inflammatory
genes as well as a downregulation of immune functions, while
GFAP-positive cells indicated different states of reactivity.
Pathway analyses indicated that the PI3K-Akt signaling pathway may
be involved in the generation of NeP in
CKCSs
with
SM. Conclusion: These findings provide new insights into the complex
molecular changes in dorsal horn IBA1 and GFAP-rich areas in the
presence of NeP and SM. The findings of this study serve as a
foundation for future research that may facilitate new
understandings of NeP mechanisms.
Outcomes of 87 small-breed dogs surgically treated for Chiari-like
malformation and syringomyelia
. Sung Su Park, Ji Young
Park, Ho Jae Han. Vet Surg. November 2025; doi: 10.1111/vsu.70062.
Quote: Objective: To report the outcomes of titanium mesh (TM)
cranioplasty without polymethylmethacrylate (PMMA), incorporating a
deliberate gap between the foramen magnum decompression (FMD)
surface and the TM, in small-breed dogs with Chiari-like
malformation and syringomyelia (CM/SM). Study design: Retrospective
clinical study. Animals: A total of 87 client-owned small-breed dogs
diagnosed with CM/SM by magnetic resonance imaging, all presenting
with neurologic deficits. ... Breeds included 32 Maltese, 28
Pomeranians, eight Yorkshire Terriers, nine Chihuahuas, nine
Poodles, and one Bichon Frise. ... Methods: All dogs underwent
modified FMD. A gap was preserved between the FMD surface and
the
TM to facilitate tissue integration and reduce postoperative
compressive forces. Clinical status was assessed based on neurologic
improvement, medication dependency, and need for revision surgery.
Results: Surgical decompression with the modified TM technique
resulted in sustained clinical improvement in most dogs. A total of
76 dogs (87%, 76/87) showed long-term improvement, and no revision
surgeries were required during a median follow-up of 35 months
(range: 27–73 months). Follow-up evaluation comprised postoperative
computed tomography (CT) imaging at 6 months, as well as structured
telephone interviews with owners to monitor clinical status. Only a
small subset of dogs (13%, 11/87) required continued medication
after surgery due to recurrence of signs. Conclusion: Retrospective
analysis showed that the modified TM technique, using a deliberate
gap, was safe and effective in small-breed dogs with CM/SM,
successfully preserving the decompression space and maintaining
long-term neurologic stability. Clinical relevance: The modified TM
technique approach achieves durable neurologic improvement and
minimizes long-term complications in small-breed dogs, demonstrating
practical utility in managing this clinically challenging
population. ... Image (F) is photograph showing a contoured
veterinary titanium mesh plate fixed to the occipital bone with
1.5-mm cortical screws (4 mm length). The mesh follows the occipital
curvature, maintaining a 5–6 mm decompression gap over the
cerebellar surface and avoiding contact with the dorsal arch of the
first cervical vertebra.
Relationship between sleep and pain in
Cavalier King Charles
spaniels
. Allie R. Sherman, Mindy A. Quigley,
Stephen R.Werre, John H. Rossmeisl, Rell L. Parker. Vet. Rec.
December 2025; doi: 10.1002/vetr.70175. Quote: Background:
Cavalier King Charles spaniels (CKCS)
have a high frequency
of chronic pain and may have abnormal sleep patterns. ... It is
recognised that
Cavalier King Charles spaniels (CKCS)
with chronic pain secondary to Chari-like malformation (CM)
experience abnormal sleep. Brachycephalic dogs are at risk for sleep
disorders and are also predisposed to pain syndromes such as CM. ...
CKCS
have a high prevalence of CM, which causes
chronic central NeP, most commonly related to the presence of
syringomyelia (SM).9 There is a spectrum of pain phenotypes
secondary to CM and SM, as approximately 50%–70% of
CKCS
dogs have SM secondary to CM, whereas only 15%–33% of these dogs
will display phenotypes and behaviours associated with NeP. This
disorder is similar to the human disorder of type I Chiari
malformation, as the pain phenotype develops over time and the
underlying pathology is similar. Previous studies have reported
sleep abnormalities in
CKCS
dogs with CM/SM,
including abnormal head position during sleep or crying out during
sleep. Using the SNoRE 3.0 and NeP instruments, we asked owners
about their perceptions of dog sleep quality and NeP. Our primary
hypothesis was that dogs with a higher NeP score would be more
likely to have abnormal sleep patterns and sleep disturbances, as
measured using the SNoRE 3.0 survey. The NeP score includes a QOL
question, and we hypothesised that dogs with worse sleep scores
would also have a poorer owner-perceived QOL. ... Methods: Owners of
CKCS
were recruited to complete an online survey,
including demographic information, the SNoRE 3.0 sleep survey, the
NeP survey and QOL. Results: ... We received responses concerning 68
dogs. Some owners had multiple dogs and filled out the survey once
for each dog, so 45 owners responded to the survey. All dogs were
reported to be purebred
CKCS
. The median age of
dogs was 5.0 years (range 0.55– 15.1 years). Twenty-three dogs were
reported to be male castrated, 23 female spayed, 13 male intact and
nine female intact. Four dogs were reported to be currently
receiving pain medications, which included gabapentin or pregabalin.
Three dogs were reported to have previously diagnosed neurological
conditions; these responses included CM, SM and fly biting, and the
certainty of the diagnosis was not confirmed. ... The median SNoRE
3.0 score was 12.5, the median NeP score was 0.83 and the median QOL
score was 2. The Spearman correlation coefficient between SNoRE 3.0
and NeP was 0.381 (p = 0.0012), between SNoRE 3.0 and QOL was 0.29
(p = 0.014) and between NeP and QOL was 0.58 (p < 0.0001).
Limitations: This is a questionnaire-based study with a small sample
size. Due to the study design, diagnoses are not confirmed.
Conclusions: ... This study shows that chronic pain and sleep
disorders are relatively common in this group of
CKCS
There was a correlation between poor sleep, as measured using the
SNoRE 3.0 survey, and the perceived presence of NeP, as measured
using the NeP score. It also shows that dogs with poor sleep are
perceived to have a worse QOL and further supports that the NeP
score is correlated with QOL, as shown previously. ... These data
indicate that there is a positive correlation between owner survey
responses regarding increased nighttime restlessness, worse NeP and
worse QOL. ... Sleep disturbances emerged as an important and
currently underexplored aspect of chronic central NeP in this
population of dogs, as an increased SNoRE 3.0 score was correlated
with a worse QOL.
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2026
Development and validation of the Chiari-like malformation and
syringomyelia evaluation: the CHASE questionnaire
. Amanda
Valentino, Sarah A. Moore, Stuart Fitzgerald, Susan Kennedy, Aisling
Farrell, Michael Costello, Patrick Roynard, Natasha J. Olby. J. Vet.
Intern. Med. January 2026; doi: 10.1093/jvimsj/aalaf040. Quote:
Background: Chiari-like malformation (CM) and syringomyelia (SM) in
dogs are associated with signs of neuropathic pain and itch, which
are difficult to quantify reliably. Hypothesis/Objectives: Develop
and validate the Chiari-like malformation and syringomyelia
evaluation (CHASE) questionnaire to quantify owners’ assessments of
clinical signs of CM/SM in their dogs. Animals: Twenty client-owned
healthy dogs [2
cavalier King Charles spaniels (CKCS)
and 30 CM/SM affected dogs [all
CKCSs
]. Methods:
The CHASE questionnaire was developed using an iterative sampling
design, reliability and normal scores were established in healthy
dogs. A double-blinded, randomized, crossover study design was
conducted using pregabalin and placebo, with CHASE as the primary
outcome. Physical and neurologic examinations, activity monitors,
quantitative sensory testing (QST), and quality of life assessments
(QOL) were performed alongside the CHASE questionnaire at each time
point. ... Questions were framed as "Please think about your dog's
behavior over the past week and use the scale to indicate how much
he/she is…[descriptor]." A 7-point Likert scale was presented for
each question, with 0 representing "not at all" and 6 being
"couldn’t be more." [The 5 categories of desciptors were: Scratching
(displaying visible signs of irritation), Anxious (displaying
nervousness or worry), Sensitive (easily upset or hurt),
Uncomfortable, and Restless.] ... In addition, the examining
veterinarian completed a 7-item CM/SM scoring assessment including a
veterinarian assessment of condition-specific pain levels. ... The
CHASE questionnaire is not a diagnostic test but assesses treatment
response. Sensitivity and specificity usually are measured against a
gold standard method for evaluating the presence or absence of a
disease. Here, it evaluated response to treatment. ... Results:
Baseline CHASE scores were significantly higher in CM/SM dogs
compared with healthy dogs (15.3 ± 4.8 vs. 1.4 ± 1.8; P < .01), with
score ranges of 6-24 and 0-6, respectively. The CHASE scores in
CM/SM dogs were moderately repeatable from screening (15.1 ± 4.4) to
baseline (15.1 ± 4.7) and decreased significantly with pregabalin
compared with baseline and placebo. The questionnaire had strong
internal consistency and differentiated pregabalin from placebo with
63% sensitivity and 76% specificity (area under the curve = 0.67).
No significant differences in QOL, QST, or activity levels were
identified. Conclusions and clinical importance: We validated the
use of the CHASE questionnaire to quantify clinical signs associated
with CM/SM and distinguish treatment outcomes when other assessments
failed. ... Our results support that the CHASE questionnaire is
capable of successfully capturing behaviors that are believed to be
a consequence of neuropathic pain and itch in dogs with CM/SM. This
conclusion is strongly supported by the responsiveness of the
component questions and overall score to the clinical signs of the
condition. The final CHASE questionnaire was simple to administer
remotely, owners answered the questions consistently, and it
discriminated between healthy and affected dogs. In addition, it
detected appropriate changes in clinical signs in canine CM/SM
patients receiving a treatment of known efficacy in a
double-blinded, randomized controlled trial. Robust repeatability
also was observed, evidenced by the lack of significant difference
in CHASE scores at both timepoints in the healthy cohort and between
screening and baseline CHASE scores in the CM/SM cohort.
MRI-derived three-dimensional modelling reveals cervicothoracic
subarachnoid space narrowing in syringomyelia-affected
cavalier king charles spaniels
Ryan Jones, Srdjan
Cirovic, Clare Rusbridge. BMC Vet. Res. April 2026; doi:
10.1186/s12917-026-05435-6. Quote: Background: Syringomyelia (SM) is
a disorder of cerebrospinal fluid (CSF) circulation strongly
associated with Chiari-like malformation (CM) in
Cavalier
King Charles Spaniels (CKCS)
. Although CM is nearly
ubiquitous in the breed, not all affected dogs develop signs of
CM-related pain (CM-P) or Syringomyelia (SM), raising questions
about underlying mechanisms. CM-P without SM has been linked to
brachycephaly, whereas SM involves additional craniocervical
conformational changes. This study tested whether CM-P affected
CKCS
with and without SM were more likely to have
reduced cisterna magna volume and cervicothoracic subarachnoid space
(SAS) narrowing compared to each other and with
CKCS
with CM but no clinical signs (CM-N). Results: A retrospective
dataset of 168
CKCS
was reviewed. After applying
exclusion criteria and matching for body size, three groups were
analysed: CM-N, CM-P without SM, and CM-P with SM (n=10 per group).
Three-dimensional SAS models from the foramen magnum to T3/T4 were
generated by segmenting MRI data in 3D Slicer and lofting contours
in ANSYS SpaceClaim. Whole SAS volume was lower in SM cases than in
both comparison groups (ANOVA p=0.0033, η² = 0.344). Cisterna magna
volume and surface area did not differ, but the volume-to-surface
area ratio was reduced in SM affected dogs (p=0.011, η² = 0.274),
consistent with a relatively constricted SAS. Slice-by-slice
analysis revealed focal reductions in annular area and hydraulic
diameter at the occiput, C2–C6, and T1–T3, with hydraulic diameter
more sensitive to local change. Corresponding decreases in Womersley
number indicated a viscous-dominated CSF flow regime and loss of
pulsatile compliance. Principal Component Analysis confirmed
distinct clustering of SM cases, while CM-P and CM-N dogs
overlapped; displacement along the principal axis correlated with
syrinx diameter, linking morphology to clinical severity.
Conclusions:
CKCS
with CM-P and SM have global SAS
volume loss with focal constrictions, whereas
CKCS
with CM-P without SM does not differ from CM-N. These findings
support a model in which SM develops from limited cranial and spinal
SAS capacity to accommodate and redistribute pulsatile CSF flow,
altering pressure transmission along the neuraxis. The 3D
reconstruction method offers a reproducible framework for
quantifying these changes and linking structure to flow dynamics.
Limitations include incomplete neuroaxis coverage, post-SM analysis
(cause versus effect), small sample size, and single-operator
measurements.
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