Arthritis Arthritis Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In some types other organs are also affected. Onset can be gradual or sudden. There are over 100 types of arthritis. The most common forms are osteoarthritis (degenerative joint disease) and rheumatoid arthritis. Osteoarthritis usually occurs with age and affects the fingers, knees, and hips. Rheumatoid arthritis is an autoimmune disorder that often affects the hands and feet. Other types include gout, lupus,
Reactive arthritis trachomatis" is the most common cause of reactive arthritis following urethritis. "Ureaplasma" and "mycoplasma" are rare causes. There is some circumstantial evidence for other organisms causing the disease, but the details are unclear. Reactive arthritis usually manifests about 1–3 weeks after a known infection. The mechanism of interaction between the infecting organism and the host is unknown. Synovial fluid cultures are negative, suggesting that reactive arthritis is caused either by an autoimmune response involving cross-reactivity of bacterial antigens with joint tissues or by bacterial antigens that have somehow become deposited in the joints. There are few clinical symptoms, but the