DefinitionPolymyositis 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.
|Front Muscles of Trunk|
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CausesPolymyositis may be caused by a combination of genetic and environmental factors that trigger an abnormal immune response.
Risk FactorsPolymyositis is more common in women, and in people aged 31-60 years old.
SymptomsPolymyositis may cause:
- Muscle weakness
- Muscle pain
- Great effort needed to climb stairs
- Trouble rising from a chair
- Difficulty reaching overhead
- Chronic dry cough
DiagnosisThis 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
TreatmentWhile there is no cure, treatment can improve your muscle strength and function. Talk with your doctor about the best plan for you. Options include:
MedicationMedications to treat polymyositis may include:
- Corticosteroids to reduce inflammation
- Topical steroids to treat skin rash
Physical TherapyYour 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
Dietary ChangesPolymyositis 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.
Speech TherapyPolymyositis may also cause speech problems. A speech therapist can assess your condition and create a program for you.
PreventionThere are no current guidelines to prevent polymyositis.
American Autoimmune Related Diseases Association
The Myositis Association
The Arthritis Society
Choy EH, Hoogendijk JE, Lecky B, Winer JB, Gordon P. Immunosuppressant and immunomodulatory treatment for dermatomyositis and polymyositis. Cochrane Database Syst Rev . 2009;(4):CD003643.
Idiopathic inflammatory myopathy: treatment. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what. Updated April 7, 2013. Accessed July 31, 2013.
Myositis. American Academy of Orthopaedic Surgeons Ortho Info website. Available at: http://orthoinfo.aaos.org/topic.cfm?topic=A00198. Updated July 2007. Accessed July 31, 2013.
Myositis Association. Getting diagnosed. The Myositis Association website. Available at: http://www.myositis.org/learn-about-myositis/diagnosis. Updated March 2012. Accessed July 31, 2013.
Myositis Association. Myositis FAQ. Myositis Association website. Available at: http://www.myositis.org/learn-about-myositis/types-of-myositis. Updated March 2012. Accessed July 31, 2013.
Myositis Association. Treatment. Myositis Association website. Available at: http://www.myositis.org/learn-about-myositis/treatment. Updated March 2012. Accessed July 31, 2013.
NINDS Polymyositis information page. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/polymyositis/polymyositis.htm. Updated August 26, 2011. Accessed July 31, 2013.
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- Reviewer: John C. Keel, MD
- Review Date: 06/2013
- Update Date: 06/03/2013