Arthritis

Arthritis is a general term for several related diseases where the body's immune system attacks the connective tissue in joints. This results both in localized swelling of the joints and a reduction of the lubricating tissue that exists to allow joints to move freely. As a result, moving the joints will often result in bone-to-bone contact which is very difficult and extremely painful. The pain of attempting to move the joints increases the inflammation and eventually worsens the pain. Joints can continue to be painful even when they are not being moved. The range of motion of major and minor muscle and bone groups starts to lessen as movement becomes more difficult, and walking can become difficult or impossible.
Although arthritis is often seen as a disease of the elderly, it can strike people of any age.
Treatment is designed to lessen the symptoms and allow the patient a fuller range of movement. Aspirin and Ibuprofen, in larger than normal doses, are the preferred treatment as in addition to reducing pain, these drugs reduce the inflammation and promote healing.
Rheumatoid arthritis is a chronic, systemic autoimmune disorder that affects many tissues and organs, but primarily the joints. It often progresses to destruction of cartilage. It is very common, affecting about one in every 100 people, although onset is usually between the ages of 40 and 50. It can be painful and disabling and can lead to a loss of function and mobility. Although it can be diagnosed by symptoms alone, there is a blood test for rheumatoid factor that is definitive. It's not related to rheumatic fever, but has many of the same symptoms. In addition to painkillers and steroids, RA can also be treated with drugs that target the antibodies involved. Rheumatoid arthritis is a frequent differential diagnosis, but has never been the underlying condition on House M.D..
Psoriatic arthritis is a genetic inflammatory disease that usually affects the joints, skin, and nails of the hands and feet.
Arthritis at Wikipedia
Arthritis