Rheumatoid Arthritis

Rheumatoid arthritis is the second most common joint disease, affecting approximately one to two percent of the adult population, though it can occur at any age. The cause of rheumatoid arthritis is not known, though two primary risk factors are age and female gender. The wrist, knee, hand, and foot joints are most affected. Rheumatoid arthritis is systemic in nature and thus affects tissues throughout the body, with joint involvement being bilateral. Changes in the synovial tissue alter synovial fluid production and ultimately damage the cartilage, bone, and adjacent tissues. Most of the extra-articular tissue changes occur over the long term, though some systemic symptoms are present from the onset.

Symptoms of rheumatoid arthritis usually start slowly and may be systemic complaints such as fatigue, weight loss, weakness, and general joint pain. In contrast to the stiffness felt with osteoarthritis, stiffness with rheumatoid arthritis lasts for more than 30 minutes. One criterion for diagnosis is morning stiffness that lasts at least an hour. Patients will often have periods during which their symptoms are worse, called exacerbations'the involved joints may be swollen, warm, and painful. As with osteoarthritis, the joint becomes deformed and loses motion as the disease progresses. Joints are more likely to become unstable with rheumatoid arthritis than with osteoarthritis, perhaps because of the changes in the tissues outside the joint. Because it is systemic, rheumatoid arthritis can affect the heart, lungs, and gastrointestinal systems, among others.