Health Conditions

What causes it?

Little is known about what causes most types of arthritis. The following can cause arthritic diseases:

• an overly active immune system that results in your body attacking itself
• imbalances in your body's chemistry that allow certain chemicals to build up in your body and get deposited into your joints
• injuries
• birth defects
• heredity-some types of arthritis run in families
• infections
• wear and tear on the joints

In normal joints, muscle, tendons and bursa (a pad-like sac) support bones. The joint's inner lining, the synovium, lubricates it by releasing a slippery fluid. Cartilage cushions the ends of the bones, keeping them from rubbing together during normal movement. In osteoarthritis, the cartilage breaks down and the bones rub together. Bone ends may thicken and form growths called spurs. The joint then loses its normal shape; joint alignment changes, and pieces of cartilage or bone may float in the joint area, causing pain and making movement difficult. Rheumatoid arthritis is believed to be the result of a malfunctioning immune system. Elements of the body's immune system fail to recognize natural body chemicals as "normal" and attack these chemicals as if they were a foreign material. The joint lining thickens as it becomes inflamed and damages cartilage and bone, sometimes causing deformity.

Normal joints are cushioned by cartilage and a fluid lubricant. In arthritis, the cartilage and bone erode.