DefinitionBy Mayo Clinic staff
Polymyositis (pol-e-mi-o-SI-tis) is a persistent inflammatory muscle disease that causes weakness of the skeletal muscles, which control movement. Medically, polymyositis is classified as a chronic inflammatory myopathy — one of only three such diseases.
Polymyositis can occur at any age, but it mostly 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 are. Polymyositis signs and symptoms usually develop gradually, over weeks or months.
Remissions — periods during which symptoms spontaneously disappear — are rare in polymyositis. However, treatment can improve your muscle strength and function.
- NINDS polymyositis information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/polymyositis/polymyositis.htm. Accessed May 26, 2011.
- Baer A. Advances in the therapy of idiopathic inflammatory myopathies. Current Opinion in Rheumatology. 2006;18:236.
- Dalakas MC. Inflammatory disorders of muscle: Progress in polymyositis, dermatomyositis and inclusion body myositis. Current Opinion in Neurology. 2004;17:561.
- Miller ML. Clinical manifestations and diagnosis of adult dermatomyositis and polymyositis. http://www.uptodate.com/home/index.html. Accessed June 1, 2011.
- Di Martino SJ, et al. Newer therapeutic approaches: Inflammatory muscle disorders. Rheumatic Disease Clinics of North America. 2006;32:121.
- Koski CL, et al. Intravenous immunoglobulin use for neurologic diseases. Journal of Infusion Nursing. 2006;29:S21.
- Baer AN, et al. Polymyositis & dermatomyositis. In: Imboden JB, et al. Current Rheumatology Diagnosis & Treatment. 2nd ed. New York, N.Y.: The McGraw-Hill Companies; 2007. http://www.accessmedicine.com/content.aspx?aid=2726184. Accessed June 6, 2011.
- Cordeiro AC, et al. Treatment of inflammatory myopathies. Postgraduate Medical Journal. 2006;82:417.
- Walker UA. Imaging tools for the clinical assessment of idiopathic inflammatory myositis. Current Opinion in Rheumatology. 2008;20:656.
- Miller ML, et al. Initial treatment of dermatomyositis and polymyositis in adults. http://www.uptodate.com/home/index.html. Accessed June 1, 2011.
- Miller ML, et al. Treatment of recurrent and resistant dermatomyositis and polymyositis in adults. http://www.uptodate.com/home/index.html. Accessed June 1, 2011.
- Dimachkie MM. Idiopathic inflammatory myopathies. Journal of Neuroimmunology. 2011;231:32.
- Medications. The Myositis Association. http://www.myositis.org/template/page.cfm?id=304. Accessed June 9, 2011.