Chiari malformation and Lecture synopsis syringomyelia Canine Chiari & Syringomyelia • What is syringomyelia? • Clinical signs of syringomyelia • Treatment of syringomyelia • Genetics of syringomyelia • Prevention of syringomyelia

Clare Rusbridge 2013 ©

www.inkymousestudios.com, Picture Henny Van De Berg

1 The skull is a box containing the brain, blood vessels and cerebrospinal fluid Syringomyelia Blood arrives from heart obstruction of cerebrospinal fluid movement Blood vessels Blood vessels

C C S Brain Brain S F F

Choroid Plexus - produce CSF CSF flow Foramen magnum Arachnoid granulations – absorb CSF Skull Skull

2 Blood returns to heart Blood arrives from heart

Blood vessels Blood vessels Blood vessels

C CC Raised pressure C S S S Brain Brain Brain S F F F F

Skull Chiari Skull Chiari Skull Jet of fluid

3 Clinical signs – CM/SM Unusual sleeping posture / Syringomyelia PAIN interrupted sleep

Syringomyelia - fluid-filled cavities in the spinal cord Before medication After medication Due to obstruction of cerebrospinal fluid movement Picture Mrs S Smith

Pain face Picture Ms P Persson Picture – Tania Ledger

4 Unwilling / pain on jumping Poor exercise tolerance CM associated pain Unwilling to do stairs Pain on picking up

Minnie-May Collins enjoys agility Cartoons - Thanks to Tania Ledger (www.cavaliermatters.org) Picture – Tania Ledger

5 Canine CM/SM Dorsal horn damage in pain are more likely to have a wide Allodynia - Shoulder scratching Pain - Most common clinical sign syrinx with dorsal grey column damage Especially • Walking • Excited • Touched • “clothing” – neck collar Not Painful Painful – snoods • Breeders call

Chiari-like malformation associated pain “air guitar” Picture Jemima Harrison

6 Scoliosis / Torticollis Does pain affect your outlook on life?

Imbalance information telling Association between neuropathic pain score and Dorsal grey brain which way is “up” behavioural signs suggesting fear and or anxiety column damage more likely with wide syrinxes Owners perception of a poorer quality of life Rutherford L, et al (2012) Vet J. doi:10.1016/j.tvjl.2012.05.018

7 Treatment – surgical Treatment of syringomyelia Cranial cervical decompression Prognosis Surgery usually successful at reducing the pain but… • Syringomyelia is still present! • May still have discomfort /scratching • ~ 50% deteriorate by 2.5y post-op

Picture Henny Van De Berg

8 If associated hydrocephalous Cranial cervical decompression After FMD -pre and post op MRI Meninges is cut -shunting ventricles and tacked back B4 intraventricular shunt 15 months post surgery

4 months post-op Bone removed from skull & atlas Pre-op

Some advocate leaving open, some graft dura, others cover bony defect (cranioplasty)

9 Prognosis Medical Treatment Medical Treatment Medical management Drugs which reduce CSF production Analgesics • Guarded if… • NSAIDS – wide syrinx • Cimetidine 5-6mg/kg 2-3 x daily • If inadequate add gabapentin +/- NSAIDS – first clinical signs before 4 years of age. • If inadequate • Omeprazole at 0.5-1.5mg/kg 1x daily • Signs progress in ¾ CKCS with CM+/-SM – reconsider surgery despite medical treatment (study of 48 dogs) – Switch from gabapentin to pregabalin • Diuretics? – Many still enjoy reasonable quality of life – Consider switching NSAIDs – Consider opioids – 15% euthanatised CMSM – Consider “other” (tramadol, amantadine) – Live with CMSM and die from MVD • Anecdotal evidence of effectiveness only – Consider corticosteroids Plessas IN, et al. Long-term outcome of Cavalier dogs with clinical signs associated with Chiari-like malformation and syringomyelia. The Veterinary record. 2012. doi:10.1136/vr.10044

10 Inheritance of SM Genetics Breeds CM/SM • Any toy breed • Moderately high hereditability • Especially – SM = 0.37 (maximum is 0.64) – Cavalier King Charles spaniel – King Charles spaniels • What does that mean? – Griffon Bruxellois – Complex inheritance involving >1gene. – • ? genes at two or more loci interact to give disease – Maltese – – Expression of disease may be influenced by – Pomeranian other as yet unknown factors – – There is a good chance of “breeding it out” – Papillion – Heritability of syringomyelia in Cavalier King Charles Spaniels. Lewis et al ,. Vet J. 2009; 183 (2010) 345–347. Picture Henny Van De Berg Picture Margaret Carter

11 Prevalence of SM in asymptomatic CKCS KC / BVA CMSM MRI Scheme How are the images graded?

• Severity of CM (graded 0, 1, 2) • Severity of SM (graded 0, 1, 2)

• Age at time of scanning (a(≥5y), b(3-5y), c(1-3y))

15%

Parker JE et al (2011) Prevalence of asymptomatic syringomyelia in Cavalier King Charles spaniels. The Veterinary record 168 (25):667. Picture Henny Van De Berg

12 The need for estimated The need for estimated Mate select program (EBV) breeding values ! breeding values !

Rosie “selects” Winston (photo Carol Fowler)

Syringomyelia affected; c = < 3 years

Syringomyelia clear; a = > 5 years

13 Against publication? Question from breeder From on a online forum • Quote from “top” UK breeder • “I am worried about using ……Dog X who was • “One of the things I am most thankful for in – “…..your dogs EBV will not be published for all to see. …. scanned SM clear but …..has fathered It will up to the owner to disclose the results to whom several progeny with SM” *******(breed) is that Dog X has been they see fit to use them and with no fear of being • Only the vet and breeder of Dog X know that scanned and is clear - he is such a named and shamed.” when younger Dog X was indeed SM clear … (deservedly) popular stud dog and the • Shortly after however since rescanned and he has SM thought of him passing SM onto his many – This breeder did well at Crufts • The results of Dog X are confidential - i.e. vet puppies makes my blood run cold! Top – In the same month I saw 2 dogs with his/her cannot comment stud dogs who are SM clear can do so affix in my clinic with signs of severe SM • The breeder of Dog X quietly retires the dog much good for the breed” – In long term - not publishing protects him & • Most still consider him clear his kind ONLY. It does not help the breed • EBV will help to protect breeders

14 Genome Project Acknowledgments There are many good breeders Funding and Support SM project Canadian Institutes of Health Research Dog X Vincent Quoc-Huy Trinh Syringomyelia DNA research out there – trying their best! For the Love of Ollie Fund (Sandy Smith) CM project • Has produced over 200 puppies and his Rupert’s Fund (Nicki Hughes, Karlin Lillington and more) Philippe Lemay ` Friends of Lola Fund (Rachel Harvey, Maria Oliver) Cavalier Matters (Tania Ledger) lines continue to be popular Companion Cavalier Club Tissue Collection Scheme (Margaret Carter) Overseen by Cavalier Friends (Sue Robinson) Zoha Kibar ”Our main aim is to promote UK CKCS & Griffon Bruxellois clubs the future health and welfare of Clever Cavaliers Guy Roleau • Breeders all want to use a clear sire. DNA archive for Companion Animals Manchester Penny Knowler the cavalier but most of all to Marshfield Clinic (NIH) celebrate these little dogs for Ann Conroy Trust Clare Rusbridge – But how does one find one? Health Foundation their wonderful character, fun CKCS club of USA Health Foundation Greatly assisted by and the joy they bring to us”. The Cavalier Club of the Rand • Official scheme French Cavalier Club Alexandra Thibault Cavalier Club of Canada Karine Lachapelle Frank and Lee Pieterse – Allows clear dogs to be identified Also indebted to……. Annie Levert Stone Lion Veterinary Hospital Daniel Rochefort Carol Fowler Melanie Benard – Is a (minimum) standard / quality control Henny Van den Berg Dana Schuller-Kuyper Isabelle Thibault • Many breeders have relied on results of scans that Holger Volk, Colin Driver and RVC Claude Marineau http://cavalierpuppy.co.uk/ Diaconessenhuis Meppel CMSM screening program are not good enough Paul Mandigers and Utrecht University Yan Yang Giunio Bruto Cherubini, Dick White Referrals Statistical analysis Simon Platt and Georgia University Marie-Pierre Dube • It takes experience to interpret CMSM Natasha Olby and North Caroline State University Nick Jeffrey, John Parker and Cambridge University Sarah Blott – Feeds into an EBV Sylvie Provost

15 Thank you for listening! Appendix – BVA KC Scheme KC/BVA scheme Chiari-like malformation (CM) • Grade 0, no CM – the cerebellum has a rounded Grade 0 - No Chiari malformation shape with signal consistent with cerebrospinal fluid (CSF) between the caudal cerebellar vermis and the foramen magnum Grade 1 - Cerebellum indented (not rounded)

Grade 2 - Cerebellum impacted into, or 0 of 564 (0%) breeding CKCS herniated through, the foramen magnum. reported by CR in previous 24 m

Any questions? www.veterinary-neurologist.co.uk

16 KC/BVA scheme Proposed KC/BVA scheme Chiari-like malformation

• Grade 1 CM – the cerebellum does not have a rounded • Grade 2 CM – the cerebellar vermis is impacted shape, i.e. there is indentation by the supraoccipital bone, but there into or herniated through the foramen magnum. is a signal consistent with CSF between the caudal vermis and the foramen magnum. Which dog will get SM ?

6 of 564 (1.1%) breeding CKCS 558 of 564 (98.9%) breeding reported by CR in 24 m period (previously reported as “mild”) CKCS reported by CR in 24 m period

17 Overcrowding of the FM large cerebellar herniation not required KC/BVA scheme Why is “cut off” 3 and 5 years ?

Syringomyelia grades Prevalence of SM in asymptomatic CKCS 8 months • Grade 0, normal – (a = over 5y; b = 3-5y; c = 1- 2.9 y) Be cautious before declaring a dog safe to breed on the basis of appearance of the brain • Grade 1, CCD < 2mm Unfortunately some vets have been misinterpreting – (a = over 5y; b = 3-5y; c = 1- 2.9 y) • Grade 2, SM or pre-SM or CCD ≥ 2mm This is not CM1! 8 years – (a = over 5y; b = 3-5y; c = 1- 2.9 y)

Parker JE et al (2011) Prevalence of asymptomatic syringomyelia in Cavalier King Charles spaniels. The Veterinary record 168 (25):667.

18 Central canal dilatation Pre-syrinx i.e. oedema

Early stage on SM Best appreciated on T2W MRI

19 New guidelines

Age SM 0a 0b 0c 1a 1b 1c 2a 2b 2c

grade

>5 0a yes yes yes yes yes yes yes yes 3-5 0b yes yes yes yes

Normal 1-3 0c yes yes yes

>5 1a yes yes yes yes yes yes yes yes

3-5 1b yes yes CCD 1-3 1c yes yes

>5 2a yes yes

3-5 2b yes yes DO NOTBREED SM 1-3 2c DO NOT BREED Dog with clinical DO NOT BREED signs CM &/or SM

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