Rheumatoid Arthritis (RA) is an autoimmune disease that causes inflammation, pain and swelling in synovial joints. Common areas that are affected are the hands, wrists and feet, however, it can also affect many tissues and organs such as the kidneys, lungs, heart and blood vessels and the skin. In RA, instead of defending the body the immune system starts to attack it. This condition involves an inflammatory response of the capsule around the synovial joint (synovium), therefore being attacked. During this inflammatory attack, the cells of the synovium abnormally increase in number and causes a thickening of the synovium leading to more joint swelling. The capsule becomes permanently stretched by the inflammation, which weakens the joint as it is no longer kept in its proper position by the capsule. Sufferers are usually genetically predisposed to it and it can be caused by endogenous antigens or infectious agents.
A number of diagnostic techniques are available for detecting rheumatoid arthritis. These include erythrocyte sedimentation rate tests, C-reactive protein tests and tests for rheumatoid factor NHS Diagnosing rheumatoid arthritis.