Symptoms:

Polymyositis is a systemic disease, which means it affects the whole body. Symptoms include:

• Difficulty swallowing
• Muscle pain
• Muscle weakness in the proximal muscles (shoulders, hips, etc.) that makes it difficult to raise the arms over the head, get up from a sitting position, or climb stairs
• Problems with the voice (caused by weak throat muscles)
• Shortness of breath

Patients may also have:

• Fatigue
• Fever
• Joint pain
• Loss of appetite
• Morning stiffness
• Weight loss

A similar condition called dermatomyositis causes a reddish-purple or red rash on the face or body.

Signs and tests:

Muscle weakness and tenderness can be signs of polymyositis. A rash is a sign of a similar condition, dermatomyositis.

Tests may include:

• Autoimmune antibodies and inflammation tests
• CPK
• Electromyography
• MRI of affected muscles
• Muscle biopsy
• Myoglobin in the urine
• Serum aldolase

Patients with this condition must be carefully monitored for cancer.