Necrotizing Myelopathy is a degenerative disease that affects the spinal cord in dogs, gradually affecting mobility and sensation. It is a progressive disease, so its not known to get better without treatment, and even with treatment, its progress is usually only slowed. The problem is one of the autoimmune system. As antibodies are produced that mistakenly attack the own body, tissue in the central nervous system is destroyed or "necrotized" this phenomenon is often described as the body literally eating itself. When the muscular tissue surrounding the spinal cord is eventually eaten away, it exposes the sensitive nerve fibres of the spinal cord itself. When those are affected, disastrous results begin to happen instantaneously. Paralysis results as the control pathways between the brain and the muscles are shut down and destroyed.

Necrotizing myelopathy is a disease that can manifest in almost any breed, but it is generally very rare in all but the following: German shepherds, Belgian sheepdogs, Old English Sheepdogs, Rhodesian Ridgebacks, and Labrador Retrievers.

The disease first shows itself in a way that is very difficult to diagnose. It could attack either one or both sides of the body, and there's no way to predict which will be affected first. General signs that you might start to worry about necrotizing myelopathy include a sudden worsening weakness in the dog's hindquarters, an unsteady gait, and loss of balance or stumbling. In addition, he or she is likely to suddenly find it difficult to stand up from a sitting position, or to lie down again once standing. They'll often begin to drag one or both of the hind legs. In some cases, their weaknesses will cause the leg to turn under, that is to say that when the dog takes a step sometimes the lower part of the foot will remain pointing down and the top of their foot rather than the bottom, padded part will be the one to make contact with the ground, usually resulting in a fall. On top of all these other signs, muscular wasting is also usually apparent.

The disease is diagnosed by ruling out other causes through an extensive neurological examination which measures both response time to nerve stimulation and spinal evoked potential. In addition, radiographs will likely be taken of the spine, and a laboratory analysis of the cerebro-spinal fluid will be carried out.

If in fact your dog is diagnosed with necrotizing myelopathy, the prognosis is generally quite grim. Within 3-6 months, total paralysis can be expected, at which point animals are usually euthanized to avoid a protracted battle with inevitably painful results. The paralysis tends to make an animal prone to organ failure, especially in the heart, kidney and lungs.

Though painkillers can be used to manage pain and steroids to slow down autoimmune responses, necrotizing myelopathy is ultimately a fatal disease for which there is no cure. As such, dogs with a history of carrying this disease or their close relatives should not be bred.