Rheumatoid arthritis (RA) is a chronic, progressive, autoimmune disease characterised by inflammation of the peripheral joints of the hands, wrists, elbows, shoulders, hips, knees and feet, usually on both sides of the body.
Damage is caused by persistent inflammation of the synovium, the membrane lining the joint, with subsequent damage or destruction of the cartilage, bone erosion and joint deformities. Unfortunately, once cartilage and joints have been damaged by inflammation, they don’t heal well, so much of the treatment of RA is aimed at suppressing the inflammation so typical of the condition.
Although normally confined to the joints, rheumatoid arthritis may affect other systems such as the lungs, heart and nervous system, but this is rare. It’s now understood that there’s an immune reaction against the body's own synovial tissue, called an autoimmune reaction.