Canine Degenerative Myelopathy

What is it?

Canine degenerative myelopathy is a progressive disease of the spinal cord seen in older dogs, typically between the ages of 7 and 14 years. While the
actual cause is unknown, one theory is that the myelin sheath that protects the spinal cord is attacked by the immune system, similar to multiple sclerosis
or Lou Gehrig’s disease, resulting in a loss of communication between the nerves in the lower body and the brain. Other theories suspect toxicity or
vitamin deficiency.

This disease has a known genetic link; therefore prevention with prudent genetic testing prior
to breeding is important. This test is available from theOrthopedic Foundation for Animals and
is a simple cheek swab with a q-tip that is then submitted for genetic testing. A blood test through your veterinarian is also available. Tests need
to be performed on both parents to determine what the risk of passing on DM to any offspring might be: could they be a carrier, affected or be negative
for the DM link. For example:

  • If neither parent carries the link, then all puppies will be clear.
  • If one parent carries the link (is a carrier) and one is clear, then 50% of the puppies will be clear and 50% will be carriers.
  • If both parents are carriers, then 25% will be clear, 50% will be carriers and 25% will be affected by the disease.
  • If one parent is affected and if one parent is a carrier, 50% of the puppies will be carriers and 50% will be affected.

This outlines how important the health of breeding pairs is to the future health of the breed. This disease is a progressive, non-curable condition; anything
that can be done to prevent this devastating diagnosis for the owners and the dogs affected by this condition should be done.

Symptoms

Most pet owners first notice a loss of coordination in the back legs; this is call

ed ataxia or an ataxic gait. This staggering effect is often 
attributed to arthritis, especially because it is noticed in the later years of a dog’s life. The dog may start to drag one or both of the hind paws when
walking. This is referred to a knuckling and can be seen in the photo below.

It is important to note that this disease is not painful, but in compensating for the weak hind end, pain can occur in the neck, shoulders and front
limbs. This disease unfortunately progresses to complete paralysis, with incontinence and significant difficulty walking and balancing. If it progresses
further, the front legs are affected, and in very late stages the respiratory muscles are affected. Progression of the disease varies, with symptoms
increasing within a couple of months up to 3 years or more, typically paralysis will occur within 6 months to one year.

Diagnosis

Diagnosis is usually made only when other causes of the gait disturbance have been eliminated. Knowing the genetic makeup for the links for degenerative
myelopathy may help make the diagnosis as well.

Treatment 

Unfortunately there is no treatment that can stop the progression of degenerative myelopathy. Care is focused on comfort and maintaining mobility through
physiotherapy, water therapy, use of

 harnesses and slings, and good general nursing care, like assisting with incontinence issues. Exercise through walking with a harness, sling
or cart is important to maintain health of the dog with degenerative myelopathy. Physiotherapy is also available to assist in prolonging the length
of time that the dog can remain mobile.

 Properly fitted assistive equipment, like carts/wheelchairs, and good nursing care can extend the life of the dog by up to 3 years, versus dogs
that do not receive any physiotherapy who are typically totally paralyzed by 6 months to a year. Early intervention is key in maintaining quality
of life. Interestingly, in the 2010 Kerry Blue Terrier Foundation health survey, only one dog was found to have passed away secondary to degenerative
myelopathy. If anyone is in need of an assistive cart, the Kerry Blue Terrier Foundation has one that can be loaned out as needed. For information about carts, wheelchairs and other items to help your Kerry, go to www.handicappedpets.com


Here is a KB T named Kelly doing her hydrotherapy work with her therapist to slow down the effects of DM. Kelly recently started showing the classic
signs of DM. In addition to other diagnostic tools, testing her blood showed that she inherited the DM gene from both of her parents, putting her
“atrisk” for the disease. Kelly seems to enjoy her weekly hydrotherapy, which has resulted in much improvement in her symptoms since the start
of the therapy. The therapy involves Kelly being on a treadmill in 90F degree gently moving water. Kelly actually looks forward to her weekly sessions. 

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