Canine degenerative myelopathy: A vet's guide

German Shepherd with canine degenerative myelopathy
(Image credit: Dave Harfield)

Canine degenerative myelopathy is an incurable disease of the spinal cord that can progress quickly. 

It is often a lengthy, challenging, and expensive process to diagnose this disease, so having the best pet insurance in place before signs of illness appear can allow owners to direct their focus towards caring for their pup. 

Keep reading to learn more about canine degenerative myelopathy, including what signs to look out for and what you can do if your dog is diagnosed with it.

What is canine degenerative myelopathy?

Canine degenerative myelopathy, previously known as chronic degenerative radiculomyelopathy, is a progressive disease affecting the white matter of the spinal cord. Initial signs include weakness of the back legs and incoordination, but this condition can deteriorate quickly. In severe cases, it can cause paralysis and eventually death. This disease has no cure, and it is similar to amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease, in humans.

Canine degenerative myelopathy is most commonly seen in large-breed dogs over the age of 8 years, but it can develop earlier than this. Breeds that are predisposed to developing this condition include German Shepherds, Welsh Corgis, Chesapeake Bay Retrievers, Rhodesian Ridgebacks, Bernese Mountain Dogs, Boxers, and Collies, among others.

What causes canine degenerative myelopathy?

Although the exact cause of canine degenerative myelopathy is unknown, a genetic mutation in the superoxide dismutase 1 (SOD1) gene has been shown to be a major risk factor. 

Degenerative myelopathy is inherited in an autosomal recessive pattern, which means that dogs typically don’t show signs of disease unless they carry two copies of the mutated gene. 

Dogs carrying one copy of the mutated gene have a 50% chance of passing it to their offspring, so dogs with at least one copy should not be bred from. It is recommended that at-risk breeds undergo genetic testing prior to breeding for this reason.

Symptoms of canine degenerative myelopathy

The early stages of canine degenerative myelopathy can look similar to other diseases like arthritis and hip dysplasia. Common symptoms of degenerative myelopathy include:

  • Hindlimb weakness
  • Incoordination
  • “Knuckling” or dragging hind paws, which may lead to hair loss and irritation of the tops of the feet
  • Swaying when standing still
  • Falling over easily
  • Difficulty getting up from sitting or lying down
  • Difficulty squatting or lifting their leg when going to the bathroom

Over time, symptoms of degenerative myelopathy progress and become more severe. As the spinal cord continues to deteriorate, muscle loss, urinary and fecal incontinence, and paralysis can occur. The disease can even spread to the forelimbs in some cases.

Is degenerative myelopathy painful for dogs?

Canine degenerative myelopathy is not a painful disease process in itself. Dogs may be painful if they have scuffed paws or if they have otherwise injured themselves due to their incoordination, however. 

Additionally, the disease is frequently seen in combination with potentially painful conditions like arthritis, which is common in older dogs.

canine degenerative myelopathy

(Image credit: Getty Images)

Diagnosis of canine degenerative myelopathy

Canine degenerative myelopathy is diagnosed by excluding other diseases with similar presentations, such as spinal injuries, intervertebral disc disease, spinal tumors, myasthenia gravis, and discospondylitis. In addition, many dogs are older at diagnosis and may have coexisting diseases with the potential to cause similar symptoms. For these reasons, the disease can be difficult to diagnose.

The diagnosis of canine degenerative myelopathy typically involves obtaining a full medical history, conducting a thorough clinical exam, and performing diagnostic tests including bloodwork and imaging. If a veterinarian suspects degenerative myelopathy, they may wish to refer the dog to a neurology specialist who can perform additional tests such as MRI, cerebrospinal fluid collection and analysis (a “spinal tap”), and neuromuscular tests.

Because the DNA test for degenerative myelopathy only determines whether a dog has the genetic mutation that puts them at risk of developing the disease, it cannot be used to confirm the diagnosis by itself. In dogs with suspected degenerative myelopathy, the genetic test can support the diagnosis, however.

Treatment of canine degenerative myelopathy

Unfortunately, there is no cure or specific medical treatment for canine degenerative myelopathy. Certain things can be done to slow the progression of disease, however. Affected dogs should be kept active for as long as possible. 

It is recommended that they maintain a lean body weight and are given regular exercise to prevent obesity. Physiotherapy has been shown to preserve muscle mass in affected dogs and maintain their quality of life. Managing co-existing diseases like arthritis (for example, with medications or the best orthopedic bed) can also relieve pain and keep dogs active.

What can you do to help a dog with degenerative myelopathy?

Several accommodations can be made to cater to a dog with degenerative myelopathy. Affected dogs should be taken for regular walks on soft surfaces like grass instead of the sidewalk. 

Boots can be considered for pups who regularly scuff their knuckles on the ground to prevent skin irritation and pain. In the house, rugs and mats can be placed on slippery floors to stop unstable dogs from slipping or falling.

For dogs who have trouble walking, you can consider a mobility aid like a sling, wheelchair, or cart—keep in mind, however, that some dogs do not do well with these tools.

How long can a dog live with degenerative myelopathy?

In general, degenerative myelopathy typically progresses over 12-18 months from the time symptoms appear.

Every dog is different, and some deteriorate quicker than others. MSD Veterinary Manual states that most dogs with degenerative myelopathy are euthanized due to disability within 1-3 years after diagnosis.

When to euthanize a dog with degenerative myelopathy

Although palliative care can keep a dog with degenerative myelopathy comfortable for some time, eventually there will come a point when euthanasia should be considered if they are suffering or if their owner cannot continue caring for them.

 This delicate situation should be considered on a case-by-case basis. Close contact with a trusted veterinarian throughout the disease process can help owners make this difficult decision when the time is right.

Dr. Diana Hasler BVM&S MRCVS

Dr. Diana Hasler graduated with distinction from the University of Edinburgh Royal (Dick) School of Veterinary Studies in 2018. She has experience working as a small animal veterinarian in general practice, where she has treated many dogs, cats, rabbits, and rodents. She has also recently branched out into the field of medical communications, doing freelance work as a medical editor and writer. Dr. Hasler currently lives in Edinburgh where she enjoys spending time with her husband Gavin and playing with their feisty tabby cat Poppy.