rheumatoid arthritis is an autoimmune disease that causes the body to turn on itself attacking tissue that normally helps protect and preserve joint function. during an ra "attack" -- known as a flare -- the immune system sends out a barrage of white blood cells to the affected joint which in turn causes inflammation in the area. it is this inflammation that is responsible for the symptoms of ra including joint swelling and pain. osteoarthritis also known as "old age arthritis" or "wear and tear arthritis" is a natural degeneration of the cartilage between joints that occurs with aging. the degeneration can be worsened by overuse or injury but its impact is limited to the affected joints.
what is rheumatoid arthritis and how is it different from "old age" arthritis?