Progressive myelopathy is a degenerative neurologic disease affecting spinal cord. The disease is similar to multiple sclerosis in humans. It destroys the myelin sheath (a protective coating around nerve fibers) and has a poor prognosis. Myelin is a substance made of fat and protein that surrounds and insulates nerve fibers; it helps speed up nerve impulse transmission both in the spinal cord and in the nerves. Degenerative myelopathy (DM) is a devastating disorder of German shepherd dogs that has been difficult to eradicate from the breed, in part because of a late age of onset and poor diagnostic tools. It may also occur in other breeds, such as Siberian Husky and other large breeds. The disorder tends to appear when the dog is about 6 years of age. The cause is unknown and possible hereditary basis is suspected.
Affected dogs experience a slow and painless loss of coordination in the hind legs. Early in the course of the disease, many dog owners erroneously assume that weakness in the hind legs is caused by a problem with the hip joint. Weakness evident on rising may be the first indication of the disease. As many German Shepherds and other large breeds commonly develop osteoarthritis of the hips and stifles and spondylosis deformans, difficulty rising may be attributed to discomfort associated with these disorders. Over the following years the weakness evolves into a partial paralysis. The dog seemingly cannot feel where its paws are, but its pain perception remains intact, as does voluntary control over urination and defecation.
Diagnosis & Treatment
Diagnosis can be difficult. Survey spinal radiographs and a myelogram may reveal only areas of possible pachymeningitis, (inflammation of the coverings of the brain, spinal cord, or both). When degenerative myelopathy is suspected, a mitogen response assay is used to confirm this diagnosis which may fail to indicate degenerative myelopathy as the cause of clinical signs. Sometimes the diagnosis can only be confirmed at necropsy when classic histopathologic lesions of degenerative myelopathy are noted in the spinal cord. Electromyograms may be performed as well to evaluate electrical activity associated with the muscle tissue of the body.
While many treatments have been attempted, none has been shown to slow down or reverse the damage. Weight control is important, as is routine daily exercise to maintain muscle tone. Anabolic steroids may be given to strengthen the muscles. Therapy includes exercise, vitamin supplementation, and EACA (epsilon-aminocaproic acid) medication. Avoiding unnecessary surgical procedures is also important to preclude permanent deterioration that can result following surgery. Physiotherapy proves to be beneficial in treating dogs with this condition. In general, animals that received intensive physiotherapy have longer survival time, compared with that for animals with moderate physiotherapy. However, in the long run, motor incapacitation is inevitable.
- Daily controlled physiotherapy increases survival time in dogs with suspected degenerative myelopathy.Kathmann I, Cizinauskas S, Doherr MG, Steffen F, Jaggy A.; Department of Clinical Veterinary Medicine, Section of Neurology, Vetsuisse Faculty, University of Bern, Switzerland
- Degenerative myelopathy.Clemmons RM. Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville
- Bruce Fogle, DVM, MRCVS. Caring for Your Dog
- Romatowski J. Degenerative myelopathy in a German shepherd