Polymyositis is a rare disease of the muscles. It usually affects the muscles closest to the trunk of the body. However, it may affect muscles anywhere in the body. The muscles become inflamed or swollen. This causes pain. The disease is progressive and starts slowly. If untreated, the muscles gradually become weaker. The pain in the muscles also increases.
Polymyositis may be caused by a combination of genetic and environmental factors that trigger an abnormal immune response.
Polymyositis may cause:
- Muscle weakness
- Muscle pain
- Great effort needed to climb stairs
- Trouble rising from a chair
- Difficulty reaching overhead
- Chronic dry cough
This diagnosis is not easy. Symptoms vary from person to person. It is often a matter of ruling out other diseases and conditions. Your doctor will ask about your symptoms and medical history. A physical exam will be done.
Tests may include the following:
- Blood tests to check for elevated muscle enzymes and autoimmune antibodies
- Electromyogram (EMG) to measure muscle activity
- Muscle biopsy
Imaging tests take pictures of internal body structures to look for muscle inflammation. This can be done with an MRI .
While there is no cure, treatment can improve your muscle strength and function. Talk with your doctor about the best plan for you. Options include:
Medications to treat polymyositis may include:
- Corticosteroids to reduce inflammation
- Topical steroids to treat skin rash
IV immunoglobulin therapy is another treatment option. It involves using an IV needle to inject extra immunoglobins (special proteins) into the body. This process may help the immune system function better and reduce inflammation.
Your doctor may recommend that you work with a physical therapist to prevent permanent muscle damage. Exercise may include:
- A regular stretching routine for weakened arms and legs
- Light strengthening as the pain lessens and function returns
Polymyositis can lead to problems with chewing and swallowing. By working with a registered dietitian, you can learn ways to adjust to these changes and get the nutrition that you need.
Polymyositis may also cause speech problems. A speech therapist can assess your condition and create a program for you.
- Reviewer: John C. Keel, MD
- Review Date: 06/2013 -
- Update Date: 06/03/2013 -