When you think of arthritis, you think of inflammation. Inflammation is a process in which the body's white blood cells and immune proteins help protect us from infection and foreign substances such as bacteria and viruses.
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.
Some, but not all types of arthritis, are the result of misdirected inflammation. Arthritis is a general term that describes inflammation in joints. Some types of arthritis associated with inflammation include:
The most common form of arthritis called osteoarthritis (also known as degenerative arthritis) is a bit of a misnomer. It is not believed that inflammation plays a major role in osteoarthritis. Other painful conditions of the joints and musculoskeletal system that are not associated with inflammation include fibromyalgia, muscular low back pain, and muscular neck pain.
When inflammation occurs, chemicals from the body are released into the blood or affected tissues. This release of chemicals increases the blood flow to the area of injury or infection and may result in redness and warmth. Some of the chemicals cause a leak of fluid into the tissues, resulting in swelling. This process may stimulate nerves and cause pain.
What Are the Results of Joint Inflammation?
Increased blood flow and release of these chemicals attract white blood cells to the sites of inflammation. The increased number of cells and inflammatory substances within the joint can cause irritation, wearing down of cartilage (cushions at the end of bones), and swelling of the joint lining (synovium).