Degenerative Myelopathy (DM) is an auto immune disease where the immune system attacks the central nervous system. This is equivalent to the human disease Multiple Sclerosis. The attack leads to degeneration of the myelin sheath (insulation) and axons (nerve fibres).
Degenerative Myelopathy is most common in the German Shepherd Dog although not exclusively. Usually the first signs of DM are worn down toe nails of a hind paw, dragging/knuckling of a hind paw. It is characterized by an increase in loss of mobility in the hind region. Affected dogs usually show a slowly progressive hind limb incoordination, clumsiness, weakness. The hind limbs start to cross over and trip the dog up. They do not appear to know where their feet are. Usually a dog will lose complete mobility of the hind legs around 8 months from the onset. Although it has not been unknown for some dogs to still be walking 2/3 years later.This is a progressive disease which can progress at different rates for different dogs. The disease does have a tendancy to wax and waine. Once a dog has lost mobility of the hind quarters the disease starts to progress toward forelimb paralysis, and eventually brainstem failure. The dog will become incontinent during the course of the disease, usually towards the latter stages.