Rheumatoid arthritis

(ROO-muh-TOYD ar-THRY-tis) An autoimmune disease that causes pain, swelling, and stiffness in the joints, and may cause severe joint damage, loss of function, and disability. The disease may last from months to a lifetime, and symptoms may improve and worsen over time.

(ROO'-ma-toid ahr-THRI'-tis) chronic systemic disease primarily of the joints ,usually around the joints, with marked swelling and muscle atrophy (shrinking).