What is it?

Polymyositis is an uncommon inflammatory disease that causes muscle weakness affecting both sides of the body. Having this condition can make it difficult to climb stairs, rise from a seated position, lift objects or reach overhead. Polymyositis most commonly affects adults in their 30s, 40s or 50s. It's more common in blacks than in whites, and women are affected more often than men. Signs and symptoms usually develop gradually, over weeks or months. While there is no cure for polymyositis, treatment - ranging from medications to physical therapy -can improve muscle strength and function.

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Signs & symptoms

The muscle weakness associated with polymyositis involves the muscles closest to the trunk, such as those in the hips, thighs, shoulders, upper arms and neck. The weakness affects both the left and right sides of the body, and tends to gradually worsen.


Diagnosis of Polymyositis may include:
- Blood tests: Might diagnose elevated levels of muscle enzymes, which can indicate muscle damage. A blood test can also detect specific autoantibodies associated with different symptoms of polymyositis, which can help in determining the best medication and treatment.
- Electromyography: Can help to determine the distribution of the disease by testing different muscles.
- Magnetic resonance imaging (MRI): An MRI can assess inflammation over a large area of muscle.
- Muscle biopsy: During this test, a small piece of muscle tissue is surgically removed for laboratory analysis. Analysis may reveal abnormalities, such as inflammation, damage, certain proteins or enzyme deficiencies.


Although there's no cure for polymyositis, treatment can improve muscle strength and function. The earlier treatment is started in the course of polymyositis, the more effective it is - leading to fewer complications. However, as with many conditions, no single approach is best; treatment strategy is based on symptoms and how well they respond to therapy.

The most commonly used medications to treat polymyositis include:
-Corticosteroids: Drugs such as prednisone can be very effective in controlling polymyositis symptoms.
-Corticosteroid-sparing agents: When used in combination with a corticosteroid, these drugs can decrease the dose and potential side effects of the corticosteroid.
-Rituximab (Rituxan)

Depending on the severity of the symptoms, treatments may include:
-Physical therapy: A physical therapist can maintain and improve strength and flexibility.
-Speech therapy: If your swallowing muscles are weakened by polymyositis, speech therapy can help to learn how to compensate for those changes.
-Dietetic assessment: Later in the course of polymyositis, chewing and swallowing can become more difficult. A registered dietitian can teach how to prepare easy-to-eat, nutritious foods.

Surgical and other procedures
-Intravenous immunoglobulin (IVIg) is a purified blood product that contains healthy antibodies from thousands of blood donors. These healthy antibodies can block the damaging antibodies that attack muscle in polymyositis. Given as an infusion through a vein, IVIg treatments may need to be repeated regularly for the effects to continue.

☝️ This is not a substitute for professional medical advice. Please consult with your physician before making any medical decision.

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