Inflammation is a process in immune system. In some diseases, however, the body's defense system (immune system) triggers an inflammatory response when there are no foreign substances to fight off. In these diseases, called autoimmune diseases, the body's normally protective immune system causes damage to its own tissues. The body responds as if normal tissues are infected or somehow abnormal. There are a number of treatment options for inflammatory joint diseases including medications, rest, exercise, and surgery to correct joint damage.