Chiari malformation occurs in dogs and, in some breeds, such as the cavalier King Charles spaniel, it is very common indeed. The Cavalier is a lovable and loving spaniel that was established as a breed in 1928 in response to a reward offered for recreating a spaniel similar to those depicted in portraits of the era of the British King Charles II. Their friendly disposition ensures that they are one of the most popular toy dogs in Britain, and they are also increasingly common in other western countries, including the USA.
Clare Rusbridge, a veterinary neurologist working here in England, met her first dog with Chiari malformation, ‘Beau’, in 1995. Beau had been sent to Clare because he had a forelimb, (i.e., arm), weakness. In addition, he appeared to suffer from intense neck and shoulder irritation, especially when he was walked with a neck collar and leash. A consequence of this was that he scratched in the air with one hindlimb whilst walking. At first Clare was bewildered, and despite many tests, she could not find the cause of Beau’s strange signs. It subsequently became apparent that Beau was not the only Cavalier with this scratching behaviour. Finally, in 1997, Clare was able to get access to a MRI scanner that could image animal spinal cords. Five dogs, including Beau, had a scan revealing that they all had syringomyelia and a Chiari malformation. Eight years on and hundreds of Cavaliers all across the world have now been diagnosed with the disease.
Cavaliers with syringomyelia usually have their first signs between 6 months and 3 years of age; however, dogs of any age may be presented. Progression of the disease is very variable. Some dogs have the tendency to scratch with mild pain only and other neurological signs never, or very slowly, develop. Others can be severely disabled by pain and exhibit neurological deficits within 12 months of the first signs developing. Many people suffering with syringomyelia may find the clinical signs experienced by dogs familiar. Pain is by far the most important feature of the disease. Many ask the question, “How can you tell a dog is in pain?” It is not very difficult, especially if the dog in question screams for apparently little reason, i.e., having its ear groomed. Once friendly, pets may become withdrawn and stop wanting to play. Owners often report that their dog is worse at night; when first getting up; during hot or cold temperature extremes; when excited; or related to posture, i.e., preferring to sleep with head elevated. The dog may seem to be overly sensitive to touch on one side of the neck / ear / shoulder / chest and often scratch at that area. Some dogs develop a scoliosis and some have weakness. Treatment of dogs is very similar to humans with the same condition. The bond between dog and owners can be as close as between humans, making it very difficult to make decisions about treatment such as surgery.
Amber Atha, a Cavalier King Charles Spaniel
with scoliosis resulting from syringomyelia