What is polymyositis?
A person with polymyositis has inflammation of the muscles, resulting in muscle weakness. The cause of polymyositis is unknown. Polymyositis may result from an abnormal immune system, which normally fights infection. The immune system mistakenly attacks normal muscle tissue, causing inflammation and breakdown of the muscle cells. The cause of the abnormal immune system in polymyositis is unknown.

What are the symptoms of polymyositis?
The most common symptom of polymyositis is muscle weakness. Initial symptoms of polymyositis include arm weakness, leg weakness, and fatigue. Additional symptoms of polymyositis may include difficulty swallowing, diminished voice, hand tremor, muscle pain, muscle swelling, and joint pains.

How does the doctor treat polymyositis?
Treatment for polymyositis may include oral corticosteroids, medications that suppress the immune system, regular exercise, and physical therapy.