What is syringomyelia?

Syringomyelia (sir IN go my EEL ya), or SM, is a potentially painful condition caused when a cavalier’s skull is too small for its brain, because of a malformation -- the Chiari-like malformation (CM), similar to the Chiari malformation in humans. CM often forces the brain to squeeze (herniate) into the opening into the spinal cord. This obstructs the cerebrospinal fluid (CSF) circulating around the brain and spine, causing pressure to rise, similar to placing a thumb over the nozzle of a garden hose. This turbulence is believed to create pockets of fluid (syrinxes) in the spinal cord that press on nerves, causing pain and disability. Unfortunately, there is no cure for SM -- the aim of treatment is to alleviate pain.

Typical symptoms may include ONLY ONE, or often, SEVERAL, of these signs:

  1. excessive scratching, especially at ears, head, face, neck, shoulders (but not all SM dogs scratch!)

  2. 'air scratching' (the hind leg makes no body contact, often seen when walking the dog)

  3. scoliosis (especially in young dogs), where the dog's neck and spine bend into a 'C'

  4. weakness in the legs

  5. pain, especially around the head, neck, spine, sides and/or legs

  6. sudden yelping for no reason

  7. flipping around to bite at the hindquarters

CM/SM is often misdiagnosed by vets and owners as:

  1. allergies

  2. ear problems

  3. spinal/disk problems

Why is it appearing in cavaliers?

No one is really sure, but it is likely due to a small and widely affected gene pool (the breed was re-created in the 1920s). While CM/SM appears in several other small breeds, the vast majority of cases seen so far are cavaliers. In research samples from several international studies, at least 85% of cavaliers had CM, and 30% to 70% also had SM (depending on the age of the dogs). Many cavaliers with SM do not seem to be symptomatic, but symptoms also are often mistaken for other problems. Many researchers and breeders believe SM is now a leading health issue in the breed, along with mitral valve disease (MVD).

What other breeds are affected? Breeds with diagnosed cases of syringomyelia include the Affenpinscher, Bichon Frise, Boston Terriers, Bulldogs, Cavaliers, Chihuahuas, French Bulldogs, Griffon Bruxellois, Havanese, King Charles Spaniel, Miniature Dachshunds, Maltese, Miniature Pinscher, Miniature and Toy Poodles, Papillons, Pekingese, Pomeranians, Pug, Shih Tzus, Staffordshire Bull Terriers, Yorkshire Terriers and several crossbreeds from these breeds. You can read more about donating for SM research scans for Griffon Bruxellois here.

What causes CM/SM?

Researchers believe CM/SM is polygenetic -- carried on several different genes that have to combine in particular ways. There seem to be separate genes for CM and SM. CM/SM affects all four breed colours, and lines from all over the world. Puppies as young as 12 weeks have been diagnosed, and CM/SM may affect a dog at any age, though more severely affected cavaliers tend to display symptoms before age four (early onset SM). No fully clear lines have been found, anywhere in the world. Beware any breeder claiming their lines are clear for this condition!

Finding a healthy puppy:

It is no longer adequate for breeders to say they have no problems with SM simply because they have never known of a case in their lines. Breeders who do scan, routinely find some cavaliers with no symptoms that scan with syrinxes (SM), often dogs they may have assumed to be clear of this problem. Breeders also home almost every puppy they breed to pet homes, which never contact the breeder again, even in the case of severe illness in their dog. So stating that there’s “no known SM” in a line is meaningless. 

When seeking a breeder, look for a puppy from breeders who can show you scan certificates for their dogs and who are open about discussing this widespread health problem. Testing is not a guarantee of a healthy puppy, but demonstrates a breeder is making the best effort available to evaluate their breeding dogs and therefore more likely to be following best breeding practice  -- but you should ask if they work with recommended breeding protocols. You can get detailed advice on finding a scanning, health focused breeder HERE.

If you want to learn more about SM and cavaliers, visit these resources:

  1. SM researcher Dr Clare Rusbridge’s website (especially see her SM FAQ)

  2. The SM Cavalier Infosite

  3. The Cavalier Health website

  4. The Cavalier Campaign website

  5. The Cavalier Matters website

  6. The CKCS InfoCenter pages on SM (which explains MRIs and scans too)

  7. For the Love of Ollie, a website and fundraising book about one cavalier’s struggle with SM


About syringomyelia in cavaliers