Canine Degenerative Myelopathy and My Experience
What Is DM?
DM or Canine degenerative myelopathy is the incurable, progressive degeneration of a dog's spinal cord which results in a general paresis of the back legs. It is similar in many ways to amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) in humans.
Halfway through November 2003, our dog Tsjip was diagnosed with DM. By April 2004, she had more and more difficulty walking. Long walks had already been out of the question for a long time. She would potter around a bit outside to pee and poop, sniff around, and then go back inside. The disease progressed slowly and painlessly, until eventually her quality of life was compromised and we were faced with one of the most difficult decisions pet owners have to make.
Have You Ever Heard of Degenerative Myelopathy?
Canine Degenerative Myelopathy Symptoms
DM or ALS starts by losing control of back legs. It's causing weakness and loss/lack of coordination in the muscles. I'll describe what we saw happening to our dog from the start.
One day in November 2003 when Tsjip was 8 years old, we noticed that she was limping a bit on one rear paw. The limping was more like a series of short waggles and was initially hard to notice. At first, we thought she had misstepped, but after a few days, it didn't go away and even got worse.
We decided to see a veterinarian, and after many tests, he ruled out everything other than DM. This was awful news for us because just two weeks prior, we had lost her sister, Sarah, to Addison's disease after six years of intensive care.
What Causes Degenerative Myelopathy?
It is still unknown what the etiology of this disease is. Research has shown that a mutation in the SOD1 gene is a risk factor for developing degenerative myelopathy in many dog breeds. It presents similarly to ALS (Lou Gehrig's disease) in humans.
Before diagnosing a dog with DM, all other spinal cord disorders have to be ruled out, such as intervertebral disc disease or spinal cord tumors which present similarly to DM.
Varying opinions about degenerative myelopathy exist. Dr. Clemmens of the University of Florida likens DM to human MS. Upon the publication of his website in 1998, Dr. Clemmens had expressed an interest and desire to treat the disease like MS, but these plans were not seen through.
Dr. Coates from the University of Missouri, on the other hand, likens DM to ALS, as most scientists do today. The University of Missouri currently runs a DNA test which detects a mutation in the SOD1 gene. SOD1 is thought to be responsible for the enzyme superoxide dismutase, which manufactures the most numerous cell in the canine body. It's possible that DM genetic mutations are also breed-specific. Scientists came to this conclusion after discovering that two carrier dogs and one noncarrier dog still developed the actual disease.
Common Carriers of Degenerative Myelopathy
Degenerative myelopathy is most often seen in the following dog breeds:
- German shepherd
- Pembroke Welsh corgi
However, the gene mutation in SOD1 has been found in at least 43 other breeds, including:
- Wire fox terrier
- Chesapeake Bay retriever
- Rhodesian ridgeback
- Cardigan Welsh corgi
* dog is dragging back leg(s)
* dog's back legs show weakness
* dog is losing control of back legs
* dog's back legs are collapsing
* dog gets paralized
Tsjip and Early Symptoms of Degenerative Myelopathy
Testing for DM Is Possible
Today, it's possible to screen dogs for DM through a DNA saliva test at the Orthopedic Foundation for Animals in Columbia, Missouri. By testing the high-risk breeds, it should be possible to reduce the occurrence of DM. However, interpretation of the results should be done by a veterinarian, so he/she can interpret both lab results and clinical signs for a proper diagnosis. The following table represents the probability of gene mutation carrier status.
Possible Lab Results for DM
Some cases report that N/N dogs have developed the disease.
The dog will not develop DM but can give it to their offspring.
Likely to develop DM.
DM Dogs: Breeding and Heritability Risks
If you want to know the probability that your pup is a carrier of or at risk of developing DM, this can be calculated using a Punnett square:
- If both parents are clear, then all of the puppies will be clear.
- If one parent is a carrier and the other one is clear, then each puppy has a 50% chance of being clear and a 50% chance of being a carrier.
- If both parents are carriers, then each puppy has a 25% chance of being clear, a 50% chance of being a carrier, and 25% chance of being at risk.
- If one parent is clear and the other one is at risk, then all puppies will be carriers.
- If one parent is a carrier and the other one is at risk, then each puppy has a 50% chance of being a carrier and 50% chance of being at risk.
- If both parents are at risk, then all puppies will be at risk.
How to Treat and Exercise Your DM Dog
Once a dog is diagnosed with DM, it's irreversible and it can't be cured. All you can do is making sure your dog is comfortable. Exercising is good, but don't overdo it. Your dog will tell you when enough is enough.
We kept Tsjip going for as long as we could. She slept on a blanket because climbing in or onto something was difficult for her. This way, she had full sight of us and we had full sight of her. Her bed was also close to the outside door.
Today, you can get physical therapy or water therapy for dogs which can help potentially stall the disease process. In Tsjip's lifetime, these options were not available, at least not where I live. While doing my research for this article, I found the following on Wikipedia:
Use of a belly sling or hand-held harness allows the handler the ability to support the dog's hind legs for exercising or going up and down stairs. A 2-wheel dog cart or "dog wheelchair" can allow the dog to remain active and maintain its quality of life once signs of weakness or paralysis of the hind limbs is detected.
We used a belly sling to support her at the end. At that time, I had never seen or heard about the possibility of a 2-wheel dog cart, but I think that even if I had known, I would've chosen not to take it that far.
Tsjip and Late Progression of DM Part 1
Wheelchair Or Euthanasia
The reason why I am not in favor to use a dog wheelchair is that I want a dog to be a dog and be able to do all the things that dogs are supposed to do. The thought of a dog wheelchair looks like the invention of the year. It's helping the dog to get around again. However I wonder; is it really giving the dog a better quality of life or is it giving the owner some peace of mind?
It might be fun for walking outside, but how is a dog in a wheelchair supposed to pee and poop in the way a dog normally does? The moment the dog is back inside the house the wheelchair has to come off or the dog would not be able to lie down and then all temporary mobility will be gone again.
So if you decide to put your dog in a wheelchair: are you doing it for the dog's sake or are you doing it for your own sake. Just think about that.
Would You Use a 2-Wheel Dog Car in Case of DM?
Tsjip Stayed Playful Until the End
Tsjip was playful until the end and loved to tear our plastic bags apart (she was careful not to swallow the pieces), as you can see in this last video. This video was recorded towards the end when she had a hard time standing up.
She was not in pain through the whole ordeal, and we made the decision to put her down at the moment she either became incontinent or couldn't reach her water bowl by herself anymore. The latter came first, and so we decided to put her down.
Tsjip Playing and Late Progression of DM Part 2
We Lost Both Dogs Within 6 Months
Seeing these videos again makes me feel sad and a bit guilty, too. I always wondered if we waited too long, but you know, she wasn't in any pain at all and you can see that she was still very playful.
It's hard to lose both of your dogs within 6 months' time at a young age. We lost both to two totally different diseases, and both were irreversible and incurable.
Degenerative myelopathy is painless, for all we know, but it's heartbreaking to see this disease progress so fast.
Dogs with Addison's disease can still live a happy life, but will die at some point either from the disease or the heavy medical regimen they have to follow.
Keep a Close Eye on Your Dog
Be cautious and aware if your dog is not walking the way he/she should. If the change in gate or mobility impairment of the hind leg(s) doesn't go away, your dog could be affected by degenerative myelopathy.
More About Degenerative Myelopathy
March 2018 Update: Gene Therapy for Canine Degenerative Myelopathy
The other day I got an email from an USA dog owner, telling me that her 10 year old corgi recently had been diagosed with MD. The reason she send me this email was the following and I quote: "they would like to do a Gene Therapy study on my dog to possibly slow down the progression and ultimately it would help humans with ALS" and she wanted to know if I had heard about this study.
I had not heard about it so I searched the internet and found a lot about gene therapy, what it is and how it works. However I also found something interesting on the website of the AKC Canine Health Foundation about Gene Therapy for Canine Degenerative Myelopathy. Let's hope they will get some good results in due time.
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© 2017 Titia Geertman