Degenerative myelopathy (DM) is a progressive neurological disease affecting the spinal cord in dogs, leading to a gradual loss of coordination and paralysis. While it causes weakness and mobility issues, DM itself is not directly painful, as it typically does not involve the sensory pathways responsible for pain perception.
Understanding Degenerative Myelopathy
Degenerative myelopathy is a non-inflammatory, neurodegenerative disease impacting the white matter of the spinal cord. This white matter contains nerve fibers that transmit motor commands from the brain to the limbs. The disease causes degeneration of these nerve fibers and their protective myelin sheath, disrupting communication between the brain and the body.
A genetic component plays a role in DM, with a mutation in the superoxide dismutase 1 (SOD1) gene identified as a significant risk factor. Breeds like German Shepherds, Boxers, and Pembroke Welsh Corgis are commonly affected. DM primarily affects motor neurons and proprioceptive pathways, which control movement and body position awareness, rather than pain signals.
Recognizing Symptoms and Progression
Dogs with degenerative myelopathy show initial signs between 8 and 14 years of age. Symptoms often include gradual hind limb weakness and ataxia, a lack of coordination. Affected dogs might knuckle over on their paws, drag their feet, or appear wobbly and stumble, especially when turning.
As the disease progresses, hind limb weakness worsens, leading to difficulty rising and eventual complete paralysis of the rear end. In advanced stages, the disease can affect the forelimbs, resulting in more widespread paralysis.
Ensuring Comfort and Well-being
Although degenerative myelopathy itself is not directly painful, reduced mobility can lead to secondary problems that may cause discomfort. Maintaining a dog’s comfort and quality of life involves proactive measures. Mobility aids such as slings, harnesses, and wheelchairs provide support, allowing dogs to remain active and engaged.
Physical therapy, including land-based exercises and hydrotherapy, helps maintain muscle mass, preserve joint flexibility, and slow mobility loss. Regular hygiene is also important to prevent secondary issues like pressure sores from prolonged recumbency, or urinary tract infections with bladder control changes. These strategies help manage the disease’s indirect effects and enhance a dog’s daily life.
Ruling Out Painful Conditions
While degenerative myelopathy typically does not cause direct pain, many other conditions can present with similar signs of hind limb weakness or paralysis and are indeed painful. A thorough veterinary diagnosis is necessary to differentiate DM from these ailments. Conditions such as intervertebral disc disease (IVDD), hip dysplasia, arthritis, and spinal tumors can all cause mobility issues and associated pain.
Veterinarians can conduct neurological examinations, imaging like MRI or CT scans, and genetic testing for the SOD1 mutation to confirm a DM diagnosis and rule out painful alternatives. IVDD often presents with sudden pain, unlike DM’s gradual onset. Hip dysplasia and arthritis involve joint pain, distinct from DM’s neurological deficits.