Arthritis is the inflammation of one or more joints. Inflammation occurs in the synovium (the lining of the joint) and is usually accompanied by excess fluid accumulation within the joint space; both factors result in joint swelling. The inflammation may be due to a variety of causes and, over time, will lead to destruction of the joint with limitation of function.
The most serious form of acute arthritis is caused by bacterial infection; in most cases, a single joint becomes red, swollen and very painful. Such a clinical presentation should prompt immediate medical attention since both early surgical drainage and intravenous antibiotics are indicated to prevent joint damage. Another form of acute arthritis, involving one or more joints, is due to crystal accumulation in the joint space; gout and pseudogout are the classic disorders and the specific diagnosis is made by examining the joint fluid. A host of inflammatory arthritis conditions, usually involving multiple joints, are due to immunologic reactions to exogenous agents (viruses, bacteria, drugs, other allergens) or to one's own body tissues (autoimmune diseases); the latter include conditions such as rheumatoid arthritis, systemic lupus erythematosis and various forms of vasculitis, among others. Finally, the inflammation may be due to injury (acute or chronic) to the joint capsule; the incidence of this condition, known as osteoarthritis or degenerative arthritis, increases with age and is predisposed by genetic factors, body habitus (e.g. obesity) and one's occupation.
The treatment of arthritis varies with the specific condition but generally involves direct management of the underlying cause (bacterial infection, hyperuricemia), elimination of offending agents or conditions, exercise, physical therapy and the use of anti-inflammatory medications. The treatment of autoimmune diseases may also include immune suppression therapy which is best administered and monitored by a rheumatologist (an arthritis specialist). In some cases, damaged joints may require joint replacement surgery; this is especially common in the management of osteoarthritis of the knees and hips.
