Understanding Degenerative Myelopathy in Dogs: Causes, Symptoms, and Management
Degenerative myelopathy significantly affects dogs, often being mistaken for other conditions in its early stages. Understanding this genetic issue enables dog owners to recognize signs like limb weakness, preparing them to manage the condition effectively and provide a better quality of life for their pets.1
What Is Degenerative Myelopathy?
Degenerative myelopathy (DM) is a disease affecting the white matter of the spinal cord, leading to its degeneration. This results in hind limb weakness that progresses to paralysis, and it may eventually affect the front limbs. DM is similar to some forms of human amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. This condition is devastating for dog owners as it results in the loss of crucial functions necessary for daily activities.2
Symptoms of Degenerative Myelopathy in Dogs
Initial signs of degenerative myelopathy in dogs are subtle and typically appear in dogs over eight years old. As DM progresses, its symptoms become more evident. The progressive signs and symptoms include:3
Symptoms
Swaying in the hind end when standing
Easily falls over if pushed
Wobbling
Knuckling of the paws when trying to walk
Feet scraping on the ground when walking
Abnormally worn toenails
Difficulty getting up from a sitting or lying position
Falling down when walking or standing
Inability to walk
Paralysis of the hind limbs1
Swaying and Wobbling
Initially, a dog with DM may exhibit slight wobbling or swaying in the hindquarters when standing. The dog may also easily fall over if slightly pushed, although it does not experience pain at this stage.
Feet Scraping and Knuckling of Paws
As the disease progresses, the hind limbs weaken, causing the feet to scrape on the ground when the dog attempts to walk. This results in hair loss and skin irritation. Knuckling of the paws may occur, beginning with the hind paws, causing the dog to turn its knuckles under while trying to walk.
Worn Toenails
Excessively worn claws and wounds to the feet may develop due to the dog's impaired walking ability.
Difficulty Walking and Getting Up
The dog may struggle to rise from a sitting or lying position. Once standing, walking is notably difficult. At this stage, challenges may include climbing steps and squatting to defecate.
Falling Down
As the disease advances, the dog may easily buckle at the knees and fall due to balance loss, even without any external push.
Inability to Walk and Paralysis
Eventually, a dog with DM will fall while attempting to walk and may become completely paralyzed in the hind limbs. Over time, the disease may also affect the front limbs.1
What Causes Degenerative Myelopathy in Dogs?
Degenerative myelopathy in dogs is caused by a mutation in the superoxide dismutase 1 (SOD1) gene. This risk factor was identified in 2009.2
How Do Vets Diagnose Degenerative Myelopathy in Dogs?
The initial symptoms of degenerative myelopathy may resemble those of other diseases, necessitating a full physical examination and diagnostic testing to rule out other causes of hind limb weakness. The veterinarian will assess the dog's medical history, breed, and age. Diagnostic tests may include X-rays, CT and MRI scans, and cerebrospinal fluid (CSF) analysis. Although a spinal cord biopsy can be done, it is uncommon. Typically, a DM diagnosis is made after excluding other potential diseases.
A DNA test is available to check for the SOD-1 gene mutation and is often recommended for at-risk breeds. It is offered by multiple laboratories.
At-risk breeds include:1
American Eskimo Dogs
Bernese Mountain Dogs
Borzoi
Boxers
Cardigan Welsh Corgis
Chesapeake Bay Retrievers
German Shepherd Dogs
Golden Retrievers
Great Pyrenees
Kerry Blue Terriers
Pembroke Welsh Corgis
Poodles
Pugs
Rhodesian Ridgebacks
Shetland Sheepdogs
Soft Coated Wheaten Terriers
Wire Fox Terriers
How to Treat Degenerative Myelopathy
Currently, there is no cure for degenerative myelopathy in dogs. Managing symptoms as they progress can help maintain a dog's quality of life. Regular exercise, walking, swimming, and physical therapy are crucial. Utilization of special hind-end harnesses to assist walking, prevent foot damage, and increase traction—by walking on grass instead of concrete and placing rugs on slippery floors—can help delay the need for euthanasia.
Prognosis for Dogs with Degenerative Myelopathy
Symptoms in dogs with degenerative myelopathy worsen quickly after diagnosis. The spinal cord continues to degenerate, leading to difficulties in standing up and increasing mobility challenges over time. Eventually, the dog may become incontinent, with paralysis marking the final stage of DM.
How to Prevent Degenerative Myelopathy
Preventing degenerative myelopathy in dogs is primarily achieved through selective breeding. When considering an at-risk breed, request breeders provide results of SOD-1 gene mutation testing on the parents, confirming they carry two copies of the normal gene.
