Your pet is getting older, but you hardly consider him a senior at eight years old. He's been active, fit, and happy. But one day, you notice he's limping a bit in one of his hind legs. You think that maybe it's muscle strain, but it doesn't seem to improve even after a week. Instead, now he's looking a bit wobbly with both legs showing signs of weakness. You take him to your veterinarian, who runs a variety of tests and x-rays. Nothing conclusive, but your vet suspects it's arthritis and puts your dog on an NSAID to help make him feel better, even though he shows no pain.
This treatment has gone on for a few months, and now your dog is knuckling under with his back paws. You bring your dog into the vet, and your veterinarian runs more tests. Still, nothing conclusive. Since there is no sign of a slipped disk, your vet suggests it might be degenerative myelopathy. But what is it and how did it happen?
Definition of Degenerative Myelopathy
Degenerative myelopathy (DM), also called chronic degenerative radiculomyelopathy (CDRM), is a progressive, degenerative spinal cord disease that affects the spinal cord and nerves. Dogs start showing symptoms of degenerative myelopathy between the ages of eight and 14 years. It is similar to ALS or Amyotrophic Lateral Sclerosis (Lou Gehrig's disease) in humans. With degenerative myelopathy, the spinal cord's white matter slowly deteriorates. This matter is what controls the impulses from the brain as well as signals from the dog's body. As the disease progresses, the dog cannot control his movements, nor can he have reliable information returning to his brain from his extremities. Over time, he becomes paralyzed. Eventually even the brain is affected and the disease causes death. There is no known cure for degenerative myelopathy.
Studies have shown that degenerative myelopathy is hereditary. Dogs that have SOD1 mutation of the gene that causes it may be at risk for having degenerative myelopathy. Most dogs that have no SOD1 mutation are highly unlikely to develop degenerative myelopathy, although two dogs in the study with normal genes did develop it, meaning that there may be other genes that can cause it. At the same time, those dogs with two abnormal genes with SOD1 mutations are at high risk for developing the disease, but not all dogs who have this mutation end up having degenerative myelopathy. Dogs who look otherwise healthy may be carriers for this mutated gene, and when bred to other dogs who have one abnormal gene could produce puppies who are at risk of having this disease.
Most Affected Dog Breeds
According to the Orthopedic Foundation for Animals (OFA), the following breeds have been proven to be carriers of the gene which causes degenerative myelopathy:
- American Eskimo Dog
- Bernese Mountain Dog
- Cardigan Welsh Corgi
- Chesapeake Bay Retriever
- German Shepherd Dog
- Golden Retriever
- Great Pyrenees
- Kerry Blue Terrier
- Pembroke Welsh Corgi
- Rhodesian Ridgeback
- Shetland Sheepdog
- Soft Coated Wheaten Terrier
- Wire Fox Terrier
Other breeds and mixed breeds can have degenerative myelopathy, but OFA has not conclusively determined that those breeds have the genetic variation that causes it.
Clinical Signs and Symptoms (and similar issues that may share symptoms)
Degenerative myelopathy may have the following initial symptoms:
- Weakness in the rear end/hind limbs
- Dog swaying when he walks
- Dog's hind feet knuckling under as he walks or walking on his knuckles
- Dog having difficulty getting up after lying down
- Dog swaying even when he's standing still
- Dog dragging his hind feet and toenails when he walks, on one or both sides
- Dog falling over when pushed on from the side
- Toenails wearing down on hind feet
- Dog's legs may buckle under him
- General loss of coordination
Degenerative myelopathy may mimic other diseases and conditions. These include:
- Osteoarthritis and chronic arthritis
- Intervertebral disc disease (IVDD)
- Spinal tumors
- Hip dysplasia
- Spinal injury
Diagnosis of DM in Dogs
Diagnosing degenerative myelopathy is difficult because the only way to truly confirm if a dog has it is to perform a necropsy (autopsy) on a deceased dog. Instead, veterinarians must rule out other causes, such as the other diseases listed above. Only when a veterinarian can eliminate other causes of the manifested symptoms can the veterinarian confirm that it is most likely degenerative myelopathy. The OFA test for degenerative myelopathy is not a diagnostic tool. It will only help confirm what the veterinarian suspects only when other diseases and conditions have been eliminated. Not all dogs with normal genes can be diagnosed as being cleared from degenerative myelopathy, just as not all dogs with two abnormal genes will manifest the disease.
Common tests your veterinarian will run will include the following:
- Blood tests
- CT scan
- MRI scan
Stages of the Disease
Degenerative myelopathy has several stages. The combined stages may last up to six months to one year without treatment. With treatment, you may be able to extend your dog's life up to three years. The stages include early, mid, early-late, and late stages. Let's look at each.
These are the signs of degenerative myelopathy in its early stage:
- Weakness in one or both hind legs
- Ataxia or lack of coordination in hind legs
- Dragging the rear feet while walking, wearing down the toenails
- Difficulty walking up stairs, jumping into the car, or climbing up on furniture
- Wobbling while walking
These are the signs of degenerative myelopathy in its mid stage:
- Knuckling over the hind feet
- Buckling while standing
- Difficulty supporting the hind end
- Difficulty walking without support
These are the signs of degenerative myelopathy in its early-late stage:
- Urinary and/or fecal incontinence
- Inability to use rear legs/dragging rear legs
- Muscle atrophy
- Pressure sores
- Poor hygiene
- Loss of strength in forelegs
- Rear and hind leg paralysis
- Difficulty breathing
- Organ failure
- Whining in pain due to other conditions
- Internal or external bleeding
Treatment and Cost
There is no one specific treatment for degenerative myelopathy. Most dogs do well with physical therapy and holistic modalities as well as being fitted for assistive equipment that will help give your dog a good quality of life. Your veterinarian may prescribe medications to treat complications as they arise.
Physical rehabilitation may include:
- Exercises (both at physical therapy and at home)
Assistive Devices may include:
Holistic modalities may include:
- Chinese herbs
- Laser treatments
Costs vary quite a bit depending on what kind of treatment options you choose. Diagnostics can run into the thousands of dollars, and if you treat aggressively, you can expect to pay thousands of dollars as well.
Long-term Prognosis and When to Make Final Decisions
Unfortunately there is no cure for degenerative myelopathy, it is a progressive disease. The end result is always death. If you treat it conservatively or choose no treatment, you can expect about survival time of six to 12 months before you consider putting your dog down. You can expect at best three years if you do treat the disease aggressively, but this is the very top end and not necessarily what you can always expect. When considering whether you should euthanize your pet, consider the following:
- Is his quality of life good? Is he happy, eating okay, and enjoying life, or is he miserable?
- Is he not in pain or is he in pain your veterinarian cannot remedy?
- Does he have control over his bodily functions or is he incontinent?
While your dog's symptoms are minor, and he is enjoying life, there's no good reason to euthanize him. But when he starts becoming anxious, depressed, and miserable because of the symptoms, you should talk it over with your veterinarian about euthanasia. Another reason to consider euthanasia is incontinence simply because it will cause distress as well as prove unhygenic for him to lay in his own waste. These can lead to painful bedsores that he shouldn't have to endure. Again, if you're not sure, ask your veterinarian for advice.
Tips for Owners & Breeders
- Diagnosing this disease through DNA tests can be helpful to ensure you make the right decisions and are aware of the challenges facing you and your pup going forward.
- For breeders, knowing the background of the dogs you are breeding will ultimately ensure you're breeding and raising healthy pups for others to love for a long full and happy life.
Can my dog's DNA be tested for Degenerative Myelopathy?
DM is inherited genetically. DNA diagnostic tests can help you know if your dog will have this, or is at risk of developing degenerative myelopathy down the road. A DNA test for Degenerative Myelopathy (DM) is available for all dogs through various vendors, even mixed breeds. One option is from DNA Diagnostic Center (here).
How long does dog live with degenerative myelopathy?
Dogs who manifest symptoms of degenerative myelopathy usually live between six months to one year, if nothing is done to treat the condition. With physical therapy and assistive equipment, dogs that show symptoms may be able to live as long as three years.
Is degenerative myelopathy painful?
In most cases, degenerative myelopathy is not painful, no matter how heartbreaking it might seem. Dog that show pain usually have another problem with the degenerative myelopathy. Talk to your veterinarian about pain management for your pet.
How do I know if my dog has degenerative myelopathy?
You don't. The only way to know is to have your veterinarian rule out other conditions before deciding it must be degenerative myelopathy. Your veterinarian should give your dog a thorough exam and eliminate all other possible causes before making that determination.
How quickly does degenerative myelopathy progress?
If left untreated, degenerative myelopathy can progress to its end stage in as little as six months to a year. If treated, your dog may be able to have as long as three years.
How does a dog get degenerative myelopathy?
Degenerative myelopathy is a hereditary disease, meaning that the dog had to have parents that carried those genes and passed them along to him and his siblings. Because the SOD1 gene mutation is recessive, carrier dogs can look normal and still pass the disease onto their puppies.
Can acupuncture help dogs with degenerative myelopathy?
Acupuncture, and specifically, electro-acupuncture seems to help with pain and slow down the progression of degenerative myelopathy, at least anecdotally.
When to put down a dog with degenerative myelopathy?
Euthanizing your pet is always a personal decision. You should always take into account your dog's quality of life; if he is unhappy, incontinent, unable to walk even when assisted, or in pain, then it is time for you to let him go. If you are unable to afford the costs of physical therapy and assistive equipment, you should probably consider euthanasia once your dog is unable to walk or becomes incontinent.
How to care for a dog with degenerative myelopathy?
Dogs who have degenerative myelopathy will need to be fitted with assistive equipment such as booties, harnesses, and even specially designed wheelchairs. You will have to work with a veterinary physical therapist who will help your dog keep his mobility as long as possible through specialized exercises, hydrotherapy, and massage. You will have to plan to keep your dog on one level of your home, since he will have difficulty using stairs. You will most likely have to take your dog outside frequently, so he may relieve himself, and use a specially designed harness to help him stand.
How common is degenerative myelopathy?
Degenerative myelopathy is a relatively uncommon disease with about .19 percent of all dogs having it. It is more common in German Shepherd Dogs, as one study suggests that as high as 2 percent of all German Shepherd Dogs within the breed manifest degenerative myelopathy.