Syringohydromyelia, also known as COMS or Caudal Occipital Malformation Syndrome, is a condition where there is insufficient room for cerebrospinal fluid (CSF) to pass out of the back of the skull and down around the spinal cord. Instead of flowing gently as CSF should do normally, it seems as if the lack of space affects CSF flow in similar fashion to putting ones finger over the end of a hose and so CSF tends to jet out. This jet-effect damages delicate nervous tissue and forms cavities within the spinal cord that are the hallmark of syringohydromyelia. This condition was first described in Cavalier King Charles spaniels but has since been reported in a number of breeds. Animals are usually born with the malformation predisposing them to this condition and some develop signs within the first year of life whereas others only show signs considerably later. The main clinical sign is neck pain but some dogs show unusual behavior, scratching at the neck, weakness or disturbances of gait. Diagnosis usually depends on an MRI. Treatment usually requires surgery for the best outcome although some animals will respond to corticosteroids like Prednisone. Prognosis is often favorable; signs tend not to resolve completely with Prednisone whereas about half of all dogs treated with surgery are able to stop taking Prednisone completely.

Further Resources

ACVIM Proceedings Through VIN Require Login; For Veterinarians