Symmetrical is the key in distinguishing it from other kinds of arthritis. Add to this definition stiffness of joints after inactivity and the requirement that arthritis lasts six weeks or longer in the same joints, and we have the official American College of Rheumatology definition for rheumatoid arthritis . RA is one of the most common forms of arthritis. It affects mainly women in their forties, but it can also occur in children and in seniors over sixty-five years of age. It is an equal opportunity condition, affecting rich and poor alike.
Arthritis occurs more than half of the time in the fingers, wrists, shoulders, knees, and ankles.
Besides pain in the joints, it also causes trouble in other parts of the body, although involvement of the upper spine or lower sacroiliac joints is unusual. The vignette about Charlotte, who experienced an onset of fatigue, irritability, inactivity stiffness, muscle pain, and symmetrical joint swelling, pain, warmth, and tenderness, illustrates the most common startup of this often capricious and potentially disruptive disease. In RA, the lining of the joint, called the synovium , becomes inflamed, resulting in pain, stiffness, warmth, redness, and swelling. Inflamed cells release an enzyme that may digest bone and cartilage. One of the most common symptoms of RA is fatigue.