A lot of people have questions about dogs with weakness, usually most noticeable in the rear limbs. Why do dogs lose their strength? Many people first assume the cause is hip dysplasia, arthritis or a sore back. The answer is may be “canine Degenerative Myelopathy.”
What is Degenerative Myelopathy? (DM)
Degenerative Myelopathy is an inherited disease of the nervous system in which there is peripheral nerve fiber loss. Degeneration of nerve tissue leads to weakness of the rear limbs.
DM has been compared to Lou Gehrig’s disease and multiple sclerosis in humans. This syndrome is often seen in German Shepherds, Pembroke and Cardigan Welsh corgis, standard Poodles, Collies, Boxers and several other purebred lines. Of course, it also occurs in mixed breed dogs.
What Causes DM?
In traditional Chinese veterinary medicine, canine degenerative Myelopathy may be diagnosed as Wei syndrome. Wei syndrome is the term used for generalized weakness or wasting. An alternate TCVM diagnosis is phlegm obstruction of the Dai Mai channel.
The Dai Mai is a sort of energy pathway that runs around the waist and energetically connects the upper and lower halves of the body. “Phlegm” may clog the Dai Mai and keep the energy trapped in the upper part of the body.
The result, and what is seen by humans, is rear limb weakness in the affected dog.Symptoms are usually seen in dogs aged 8 years and older. Early signs include difficulty jumping, weakness in rear legs, stumbling, “crossing-over” of rear feet, and abrasions on the feet from scuffing.
Degenerative Myelopathy is not known to cause pain, so most dogs don’t seem distressed initially. In the early stages, DM may be difficult to differentiate from osteoarthritis and degenerative disc disease (slipped disc in the spine). Other causes of similar symptoms are inflammatory disease including bacterial and fungal infection (Valley Fever). Cancer can also affect the spinal cord and cause identical symptoms.
How is DM Diagnosed?
A diagnosis of DM is based on clinical symptoms, blood testing, radiographs (x-rays) to look for evidence of slipped disc, cancer or infection, electromyogram (testing muscle impulses), spinal taps and CT/MRI may be used in some cases. There are genetic tests available through the Orthopedic Foundation for Animals.
The tests may be ordered by anyone for a nominal fee and only require you to collect a saliva sample from the dog with a swab. The genetic test will tell you whether the dog is “clear,” a “carrier,” or “at risk” for DM. The test may be run on symptomatic or asymptomatic dogs.
Good reasons to do genetic testing are to:
Have a better idea of what to expect with a symptomatic dog Rule out DM in a symptomatic dog so that other diagnoses can be pursued Avoid breeding dogs who are carriers or at risk for developing DM.
There are no proven effective treatments for DM at this time. A regimen of nutritional supplements, special diet, exercise, and various alternative therapies (acupuncture, cold laser, physical therapy, homeopathy) may slow the progression of the disease.
Dr. Roger Clemmons, a veterinary neurologist at University of Florida, has an interesting web site with his recommendations for treating DM.
The long-term prognosis is considered poor, with most dogs losing the ability to walk within 6-12 months of diagnosis.
Difficulty with elimination of urine and feces often is a major consideration in caring for dogs with DM.
The Answers to Help Dog’s in Need of Assistance
If you have a dog with DM, you need to consider whether you will be able to provide the nursing care to keep him/her clean and comfortable. This may require several hours a day, frequent rechecks with the veterinarian, lifting the animal, cleaning excrement from the fur, and keeping them safe from danger.
It can be done, but many people are not prepared or are unable to make these lifestyle sacrifices to care for dogs with end-stage DM. If you’re seeing symptoms that might be DM, have your veterinarian examine your dog and discuss the next steps in making a diagnosis. Knowledge is power and peace of mind.