Polymyositis in Dogs: Causes, Symptoms and Treatment
Polymyositis is an inflammatory muscle disease affecting dogs, causing widespread muscle weakness and pain. This condition is similar to dermatomyositis but primarily impacts the skeletal muscles through inflammation rather than lesions or pus. While polymyositis can be painful and debilitating, understanding it can help ensure timely diagnosis and effective management, particularly for breeds more at risk.
Breeds Most at Risk for Polymyositis
Research has shown that some dog breeds have a higher predisposition to polymyositis, although the precise reasons remain unclear. Responsible ownership and genetic awareness are important when considering these breeds, as early recognition of symptoms can improve outcomes. The breeds most commonly affected include:
Recognising the Symptoms of Polymyositis
Early detection of polymyositis can make a significant difference in your dog's recovery. Some common signs to watch for are:
- Stilted or abnormal gait
- Swollen and painful muscles, especially when touched
- Muscle weakness and atrophy
- Intolerance to exercise or activity
- Enlarged oesophagus causing difficulty swallowing
- Regurgitation of food due to oesophageal dysfunction
What Causes Polymyositis in Dogs?
This condition is often linked to immune-mediated factors or secondary to other health issues. Some documented triggers include:
- Immune-mediated diseases causing muscle inflammation
- Adverse reactions to certain medications or drugs
- Underlying cancers that may provoke the disorder
- Infectious agents and protozoal infections
Diagnosing Polymyositis
A thorough veterinary assessment is vital for accurate diagnosis. Vets will collect detailed medical and family histories and may conduct several diagnostic tests, such as:
- Complete blood count and biochemistry profiles to assess muscle enzyme levels
- Urinalysis to evaluate overall health
- Creatine kinase enzyme tests indicating muscle damage severity
- Electromyography and muscle biopsy for confirming inflammation
Referral to a veterinary neurologist or pathologist is often recommended for specialised evaluation and treatment planning.
Treatment and Management
Effective treatment targets the underlying cause and manages inflammation:
- Immunosuppressive drugs, such as corticosteroids, to reduce immune system overactivity
- Antibiotics if bacterial infection is involved; completing the full course is crucial
- Discontinuing any medication suspected as triggering the condition
- Controlled exercise to gradually rebuild muscle strength during recovery
Living with a Dog Diagnosed with Polymyositis
Post-treatment care is essential. Dogs benefiting from treatment usually show rapid improvement in muscle condition. Nutritional support and regular, gentle exercise can aid recovery. Dogs with oesophageal enlargement may require:
- Multiple small, hand-fed meals daily to reduce regurgitation risk
- Close monitoring during recovery for any swallowing difficulties
Consistent veterinary follow-up supports long-term health and manages possible relapses.
Prognosis and Outlook
Most dogs respond well to treatment, especially when started promptly. The prognosis can be very good in immune-mediated cases but is more guarded if cancer is the underlying cause. Owners should work closely with their vets to monitor progress and adjust care as needed.
