Degenerative myelopathy is a chronic slow progressive disease that causes changes in the spinal cord. This progresses from hind leg weakness to hind leg paralysis to front leg paralysis.
This is caused by a progressive degeneration of the outer insulation (myelin) of the nerves supplying the muscles usually starting in the mid to lower back. This means the message telling the legs to move is not getting through effectively
This is a disease that is usually seen in dogs aged between 8 and 14 years. Owners may notice some weakness in the hind end initially and may be confused with arthritis. Dragging the feet and scuffing and wearing down of the nails is sometimes a clue that the dog may be suffering from this condition.
The signs of weakness may be intermittent initially as the problems waxes and wanes. Sometimes the weakness may be more apparent in one hind leg than the other.
Without intervention full paralysis may occur in a few months to a year.
What Causes Degenerative Myelopathy
This is a disease that is caused by a DNA mutation (SOD1). The German Shepherd is the breed that is by far the most affected but it can occur in other breeds.
The cause is a DNA mutation in a gene called superoxide dismutase 1 (SOD1). This risk factor of having this gene was identified in 2009. Prior to this discovery, genetic, nutritional, and immune factors were suggested as possible causes of DM.
What are the signs of Degenerative Myelopathy?
Weakness in the hind legs that may be mistaken for hip arthritis is often the first sign. Scuffing and wearing down of the hind toe nails may be noted by the vet or owner. There may be crossing over of the hind feet when the dogs is standing or walking. Eventually there is marked wastage in the hind leg muscles. As the disease progresses the forelegs become weak and complete paralysis unfortunately results.
The affected legs are not usually painful but the dog will be sore from the other parts of the body that have to compensate.
There is no real test to diagnose this disease effectively. Since it can appear similar to many other degenerative diseases (disc disease, spinal cancer, spinal infection) it is usually diagnosed by ruling out the other similar conditions. The testing may include neurological exam, radiographs, blood test, myelography, spinal fluid analysis, CT or MRI.
There is a test which can identify the DNA mutation which causes this condition. A negative test result rules out this disease. A positive test means an increased risk of the dog having the disease but does not necessarily mean the condition will develop.
There is no known cure for Degenerative Myelopathy. The disease progress can be slowed with appropriate rehabilitation but cannot be cured. A recent study showed laser therapy may have benefit in these patients.
Conservative treatments offered by Balance Vet Rehab that may be beneficial for these pets include:
Rehabilitation with a home exercise program is one of the few therapies that have been shown in studies to help slow the progression of degenerative myelopathy.
Daily controlled physiotherapy increases survival time in dogs with suspected degenerative myelopathy I Kathmann et al
There is new evidence to suggest laser treatment may be helpful in this disease but more studies are needed. As laser therapy only affects diseased tissue and has no adverse effects on healthy tissues it is a worthwhile consideration.
Retrospective Analysis of Two Different Doses of Photobiomodulation Combined with Rehabilitation Therapy as a Therapeutic Protocol for Canine Degenerative Myelopathy Lisa A. Miller