Understanding Degenerative Myelopathy
Dog owners are typically unaware of the many diseases that may possibly beset our pets. People tend to think that our pets will live out their lives in good health as our faithful companions as long as we give them the right food and lots of love. Unfortunately, pets are just as likely to get sick as any person no matter how well-cared for they are. One of these diseases that seemingly spring out of the blue is canine canine degenerative myelopathy or DM.
Definition
DM is a spinal cord disorder that occurs spontaneously in dogs, usually in ages between 8 and 14, although it has infrequently occurred in younger dogs. It erodes the white matter of the spinal cord as well as the peripheral nerves which control movement. It is painless, and presents the same general symptoms of that of Lou Gehrig’s disease in humans.
Cause
The cause of DM is not known, but real progress is being made in understanding it. It is suspected that the disorder may be genetic in etiology. There are more than 70 breeds that have been identified as either carriers or at risk for DM by carrying one or two copies of the mutated gene SOD1, respectively.
Some breeds are more at risk than others, and while the actual number of dogs that have DM is not known, developing the disease is not just dependent on the presence of the SOD1. It is estimated that roughly half of the Kerry blue terrier, nearly all of Pembroke Welsh corgis (91%) and wire fox terriers (90%) carry the gene but they rarely develop DM. However if both parents are at risk for DM or carriers there is a good chance that the offspring will develop DM.
Diagnosis
A DNA test for the presence of SOD1 has been developed in various research institutions to identify whether a dog is at risk or a carrier of DM. Some tests require drawing blood while others make use of the saliva.
German Shepherd dogs and other large dog breeds appear to have a higher risk of developing DM, so it is ideal to have the diagnosis early. The symptoms may not be obvious, so a pet owner has to be vigilant in observing telltale signs that will progress as the disorder advances. These include:
Early symptoms
· Lack of coordination in the rear legs
· Wobbling or stumbling
· Dragging or knuckling of one or both hind feet (nails will show unusual wear)
· Difficulty in getting up and squatting
Late symptoms
· Weakness in hind limbs
· Difficulty in standing for any length of time
Advanced symptoms
· Incontinence
· Weakness in front limbs
These symptoms do not necessarily mean the dog has DM; there are tests aside from the DNA one such as an electromyogram (EMG) to find out what neurological disorder it may be. A telltale sign that it is not DM even without any tests is when the dog exhibits pain; DM is painless. That is, unless it is DM with co-morbid disorders that produce pain i.e. arthritis.
Prognosis
Dogs with DM have a life expectance of 6 months after diagnosis, but this varies widely from as little as a few weeks to as much as three years. In some cases, euthanasia or hospice care may be recommended if the disorder is well-advanced. Dogs that retain some mobility may benefit from some treatment modalities that researchers believe is efficacious in alleviating some of the worst symptoms of DM.
Treatment
There is no known treatment for DM, but hydrotherapy and acupuncture has been known to improve the dog’s nerve health and slow down the progress of the disease. Some vets recommend supplements called N-acetylcysteine and aminocaproic acid. Pet owners may also want to invest in vitamin B-complex, C, E with selenium, and bromelain. Ask your vet about them.
A study using 22 dogs with DM investigated the effect of physiotherapy (combination massage, gait exercise, passive joint therapy, and hydrotherapy) on a dog’s survival. The study indicated that dogs that received intensive physiotherapy survived an average of 255 days, while those that received none at all survived 55 days. DM researchers agree that while DM is so far irreversible and untreatable, an early diagnosis will increase the impact of recommended therapies.
Mobility aids
DM slowly but surely takes away your dog’s ability to move around until it comes to a point that the paralysis is complete. Nerve death typically affects one or two of the rear legs, and inevitably progresses. However, there will be a period in which the dog is still able to move around although with difficulty, and this is the time to invest in mobility aids.
In many cases, a belly harness or sling is enough to help the dog get up stairs or into a car. Because DM generally affects large dogs, it may not be possible to carry the dog bodily when needed. Never use the tail instead to lift the dog’s rear legs; it is cruel and a really bad idea. Booties are also not recommended because dogs that retain some sensation in the affected limb lose whatever advantage this gives them.
For outdoors, a DM dog may benefit from regular exercise using a pet wheelchair appropriate for the dog’s size. These are readily available brand new as well as refurbished, and either will work equally well. For the budget-conscious though, refurbished is probably a better buy. At any rate make sure that the wheelchair (or dog cart as some people call them) is made of lightweight, durable and corrosion-resistant material for maximum benefit. Dogs with DM tend to make a lot of mess in the advanced stage of DM because they can no longer control waste elimination, so you need a wheelchair that will not rust.
So there you have it, a really brief run-through of what DM is all about. If you suspect that your dog has it, or your dog is among the at-risk breeds, have it tested as soon as possible. The worst thing for an anxious pet owner is uncertainty; it is better to know.
Do you have any questions or comments about DM? You may want to know more in-depth information about it. We’ll be happy to give you what you need. Let us hear all about it!