(RA) is a unique form of arthritis that is a type of autoimmune disease, in which the immune cells that normally fight off infection are instead targeted against the body itself. In RA, these immune cells attack the lining of joints, which result in the common inflammatory symptoms of pain, redness, swelling, and warmth in the joints. The joints that are classically affected include the hands (fingers and wrists), knees, ankles and feet. Usually the same joints are affected on each side of the body, and typically the symptoms are worst in the morning upon waking up. RA can also cause other systemic affects, such as inflammation of the lining of the lungs, heart and eyes. Over time, chronic inflammation can cause destruction and deformity of the joints, which is why early and aggressive therapy is very important.
RA is a completely distinct entity from osteoarthritis (OA), which is the most common type of arthritis. While OA is associated with aging, it is not caused by aging. OA results from chronic and excessive mechanical forces on the joints, causing loss of cartilage in the joints and the subsequent development of local bony changes (such as bone spurs and cysts). OA is not an autoimmune disease, and is treated in a much different manner.