Degenerative Myelopathy (DM) is a disease of the spinal cord that causes progressive paralysis of the hind legs. It used to be thought of as a condition confined to German Shepherd Dogs, but research has now found it in a number of other breeds, including Welsh Corgis and Boxers. It is also found occasionally in Cavaliers.
Typically, the disease starts at around the age of 8, with lameness in one hind leg. A noticeable symptom is dragging of the hind paws, which knuckle under and wear down the front of the nails. DM is non-painful, progressive and irreversible and there is no treatment for it, except to help the dog to stay mobile as long as possible with the help of physiotherapy and hydrotherapy. Eventually the dog will be unable to walk, may become incontinent, and the paralysis can spread to the front legs. A DNA test can identify dogs at risk of developing the disease, though not all of them will do so.
Degenerative Myelopathy is not common in Cavaliers, and hind leg paralysis can be a symptom of other diseases such as degenerating disks and syringomyelia. However, it can occur in the breed and should be borne in mind as a possibility if there seems no obvious other cause for the symptoms. It is an extremely distressing disease for both dogs and owners.