Syringomyelia

Chiari-like malformation (CLM) is where the brain of the affected dog is too large and the skull space is too small. This size mismatch causes crowding at the back of the brain and the brainstem, which obstructs the flow of the cerebrospinal fluid between the skull and spinal cord, leading to syringomyelia (fluid pockets within the spinal cord).

Several brachycephalic toy breeds are predisposed to this condition, including the Cavalier King Charles Spaniel. The main symptoms are abnormal nerve sensation and intermittent pain at the back of the dog's head and in the neck. Affected dogs are sensitive when touched at the back of the neck, the ears, the shoulders and upper chest. They often scratch their head and ears for no apparent reason and may rub their faces constantly or lick their paws excessively.

Dogs with CLM often exhibit withdrawn behavior. They may cry or scratch when they are handled, when exercising, when excited, when passing stool, and when wearing a collar. Some dogs have increased symptoms during certain times of the day. Syringomyelia is tested for with an MRI. Severity ranges from grade 0 (normal) to grade 3 (fluid filled syrinx of the spinal cord).

Although this condition can affect any purebred or mix breed dog, it is very common in Cavaliers. Cavalier Health website states that it is estimated that 70% of Cavaliers may have this condition to some degree. It can be hereditary and you should ask your breeder if they MRI test their breeding dogs.