Rheumatoid arthritis

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Rheumatoid arthritis	Rheumatoid arthritis	Rheumatoid arthritis	Rheumatoid arthritis
Synovial fluid

Rheumatoid arthritis is a chronic (long-term) disease that causes inflammation of the joints and surrounding tissues. It can also affect other organs.

RA; Arthritis - rheumatoid

The cause of rheumatoid arthritis (RA) is unknown. It is considered autoimmune disease. The body's immune system normally fights off foreign substances, like viruses. But in an autoimmune disease, the immune system confuses healthy tissue for foreign substances. As a result, the body attacks itself. 

RA can occur at any age. It usually occurs in people between 25 and 55. Women are affected more often than men.

The course and the severity of the illness can vary considerably. Infection, genes, and hormones may contribute to the disease.

RA usually affects joints on both sides of the body equally. Wrists, fingers, knees, feet, and ankles are the most commonly affected.

Review Date: 08/19/2005
Reviewed By: A.D.A.M. editorial. Previously reviewed by Stanford Peng, M.D., Ph.D., Division of Rheumatology, Washington University School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network. (4/27/2004)