Myelopathy

Myelopathy is a disease of the spinal cord that leads to progressive weakness and movement disorders in dogs.

The spinal cord connects the brain and the body. Damage leads to neurological deficits. In most affected dogs, weakness begins in the hind legs and progresses forwards.

Forms of myelopathy

Degenerative myelopathy is the most common form in dogs over eight years old. Around 85% of cases are degenerative, with the spinal cord deteriorating without any identifiable external cause. German Shepherds, Welsh Corgis and Boxers are overrepresented, but the disease now occurs in over 120 breeds.

Other forms arise from:

• Intervertebral disc herniation: Mechanical pressure on the spinal cord, often reversible if treated quickly
• Trauma: Spinal injuries following accidents or falls
• Tumours: Primary spinal cord tumours or metastases from other cancers
• Inflammation: Autoimmune reactions or infections that attack nerve tissue

Symptoms and early signs

A changed gait in the hind legs is usually the first symptom. The dog drags its paws when walking or “crosses” its legs while moving. It takes several attempts to stand up. On smooth floors, it slips more often than before.

In the further course:

• Unsteady, insecure gait (ataxia)
• Increasing weakness up to paralysis
• Muscle wasting in the hind legs
• Loss of bladder and bowel control

Dogs with degenerative myelopathy usually show no pain, which distinguishes it from disc problems.

Diagnosis

The diagnosis is made by exclusion. There is no direct test for degenerative myelopathy.

The vet first checks reflexes and gait. MRI or CT scans show whether discs or tumours are pressing on the spinal cord. If these structures appear normal, this points to a degenerative form.

A genetic test can detect predisposition; around 90% of affected dogs carry mutations in the SOD1 gene. Not every dog with this mutation actually develops the disease.

Treatment options

A cure for degenerative myelopathy is not possible, but the course can be slowed.

Physiotherapy is at the centre of every treatment. Controlled movement maintains muscle strength and coordination for longer. Swimming or treadmill training are particularly effective.

Aids to extend mobility:

• Non-slip mats for secure footing
• Support harnesses for the hind legs
• Wheelchairs for advanced cases

For other forms of myelopathy, there are specific therapies: surgery for disc herniation, cortisone for inflammation or chemotherapy for tumours.

Prognosis

Degenerative myelopathy progresses relentlessly, usually over 6 to 24 months.

On average, 12 months pass from the first symptoms to paralysis of the hind legs. If weakness reaches the front legs, the prognosis worsens significantly.

Many owners decide on euthanasia when the dog can no longer control its bladder or breathing becomes difficult. This usually happens 18 to 36 months after the onset of symptoms.

For other forms of myelopathy, the prognosis depends on rapid treatment. Disc herniation can heal completely with timely surgery.