degenerative myelopathy in dogs
Earlier this week, I was reminded of a case that I wanted to share with you that involves a 9-year-old German Shepherd that we’ll call Fighter.
Fighter saw his vet a few months ago because his owners, Mr. and Mrs. Optimistic, noticed that Fighter was walking funny. He was still eating and drinking well, had no other problems, and didn’t seem to be in any pain that the Optimistics could identify. Fighter had always been a healthy dog, and Mrs. Optimistic ran three miles with him every other day. They had kept Fighter on joint supplements (glucosamine chondroitin sulfates) since he turned 5, but they were worried that he was developing arthritis.
After a thorough physical exam (including a neurologic exam), bloodwork, radiographs and some further testing, the Optimistics were given some unfortunate news. Fighter appeared to be suffering from a disease called degenerative myelopathy (DM for short).
Degenerative myelopathy is a disease that affects middle-aged large breed dogs (such as German Shepherds, Golden Retrievers, Great Pyrenees and others). It usually presents when the pet is over 6 years old, and the presenting complaint is usually hind limb weakness, lameness or just “walking funny.” It is a disease that starts as hind limb weakness and progresses to hind limb paralysis.
The cause of degenerative myelopathy is unknown, although a genetic predisposition is suspected. The condition is a degeneration of parts of the nerves within the spinal cord that are responsible for hind limb mobility. The front legs are not affected. It isn’t a painful disease, in itself, as the nerves responsible for pain are preserved. But hind limb muscle loss does occur, and sores may develop on the tops of the back feet, as a result of the back feet knuckling over and scraping against the ground. The pet does retain the ability to control both urination and defecation, but because they have difficulty walking and/or positioning to eliminate, they may have accidents.
Diagnosing degenerative myelopathy
Diagnosis can be difficult, as there is no single test for vets to run. It involves a thorough physical/neurologic exam, bloodwork, radiographs and sometimes testing cerebral spinal fluid and advanced imaging such as a CT or MRI. Many of these tests are done to rule out other possible causes of the pet’s clinical signs. There is a genetic test that can be done to determine if a pet has certain genes that have been correlated with developing degenerative myelopathy. This test does not indicate if a pet will definitely suffer from DM, but can identify if the genes are present. This information can be especially useful for breeding animals.
Treatment and care
Unfortunately, there is no treatment for degenerative myelopathy in dogs, and eventually (usually within months to a year after diagnosis) most pets are euthanized due to the severity of their immobility. However, there are ways to help pets maintain quality of life. There are supportive therapies (such as vitamins B, C and E), and physical therapy seems to prolong the quality of life of these patients. Pain medications are generally not necessary, unless the weakness causes the pet to fall and injure themselves. There are a variety of mobility devices (such as wheelchairs, harnesses, and bands) to aide in assisting the pet, but again, these are supportive agents.
As for Fighter, he has lost his battle with degenerative myelopathy, but not before living up to his name. He was a true “fighter” until the end, and will be thoroughly missed by Mr. and Mrs. Optimistic, and all that he touched.