Polymyositis - adult

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Superficial anterior muscles

Polymyositis - adult

Definition:

Polymyositis is a relativelyuncommon inflammatory diseasethat causes significant muscle weakness.

Causes, incidence, and risk factors:

Polymyositis isaskeletal muscle disease also known as idiopathic inflammatory myopathy. The cause of this disorder is unknown. It is thought that an autoimmune reaction or a viral infection of the skeletal muscle may cause the disease.

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It can affect people at any age, but most commonly occurs in those between 50 and 70 years old, or in children between 5 and 15 years old. It affects women twice as often as men. It is more common in African Americans than caucasians. Overall, about 1 in 100,000 people are diagnosed with some formof inflammatory myopathy each year.

Muscle weakness may appear suddenly or occur slowly over weeks or months. The weakness is due to inflammation and the breakdownof the muscles.Patients with this disease mayhave have difficultyraising their arms over the head, rising from a sitting position, or climbing stairs. The voice may be affected through weakness of the throat muscles.

A similar condition, called dermatomyositis, is marked by a dusky, red rash that appears over the face, neck, shoulders, upper chest, and back.

References:

Harris ED, Budd RC, Genovese MC, Firestein GS, Sargent JS, Sledge CB. Kelley's Textbook of Rheumatology. 7th ed. St. Louis, Mo: WB Saunders; 2005:1312-1316.

Choy E, Hoogendijk J, Lecky B, Winer J. Immunosuppressant and immunomodulatory treatment for dermatomyositis and polymyositis. Cochrane Database Syst Rev. 2005 Jul 20;(3):CD003643.

Schnabel A, Hellmich B, Gross WL. Interstitial lung disease in polymyositis and dermatomyositis. Curr Rheumatol Rep. 2005 Apr;7(2):99-105.

Rosenkranz H. Polymyositis. eMedicine. March 10, 2005. Available online at: http://www.emedicine.com/emerg/topic474.htm. Accessed October 12, 2005.