Degenerative Myelopathy

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Filed Under: Neurology


DEGENERATIVE MYELOPATHY

 

Degenerative myelopathy (DM) is a common cause for gradually progressive weakness and incoordination in the hind limbs in older dogs.  Some breeds of dog are predisposed to DM, especially German Shepherds, Corgis, Boxers, Kuvasz, and Bernese Mountain dogs, however other dog breeds may also be affected.  In these predisposed breeds, there is a genetic tendency to DM as the dog ages.

Most Patients with degenerative myelopathy experience gradually worsening weakness in the hind limbs, which may slowly progress over months.  DM is not a painful disease, so dogs continue to be alert and want to be active, despite their weakness.  However, degenerative myelopathy is debilitating, and eventually, dogs with DM become unable to use the back legs at all, and may experience fecal and urinary incontinence as well.  In most dogs, this progression to being non-ambulatory occurs over 6-12 months from the time of diagnosis.

Degenerative myelopathy has recently been proven to be similar to ALS (amyotrophic lateralizing sclerosis, or Lou Gehrig's disease) in people.  There is a genetic mutation that predisposes dogs to developing DM as they get older.  Ongoing research is being done into the causes of this disease.

The diagnosis of degenerative myelopathy is made by exclusion.  Imaging studies, such as myelogram, CT scan or MRI, along with cerebrospinal fluid anaylis if needed, are used to search for any other possible causes of gradual weakness in the hind limbs, especially degenerative disc disease or spinal cord tumors and inflammatory CNS disease (meningitis).  If these are ruled out, and if the Patient has typical symptoms, then a presumptive diagnosis of degenerative myelopathy is made.

There is no treatment for DM that has been shown to reverse the symptoms or stop the disease. Nutritional supplementation is recommended (vitamin E, vitamin B complex, selenium, and other neuroprotective and anti-oxidant supplements).  Regular physical therapy is perhaps the one treatment which has been shown in clinical studies to slow the progression of degenerative myelopathy and to extend survival time.   There are also aids available to help support dogs that are weak in the hind limbs and to help improve mobility, such as slings and carts (like wheelchairs), when these become necessary. Several online support groups have been formed, in which Owners of dogs with DM and other debilitating spinal diseases, share advice and help with others, about how to improve the quality of life for their Pets.

 

A DNA test (usually a blood test) for the genetic mutation associated with degenerative myelopathy is available to see if the dog is normal, a carrier (only has one copy of the mutation), or affected/at risk (two copies of the mutation) for degenerative myelopathy.  If a dog has a normal imaging study and spinal fluid analysis along with a DNA test result of affected/at risk, this is only a presumptive diagnosis of degenerative myelopathy.  Unfortunately,  the only way to get a defininitive diagnosis of degenerative myelopathy is a post-mortem examination of the spinal cord.

 

Additional information may be found at:
www.handicappedpets.com
http://www.cvm.missouri.edu/neurology/dm/index.html