Rheumatoid arthritis

Alternative names:

RA

Definition:

A chronic inflammatory disease that primarily affects the joints and surrounding tissues.

Causes, incidence, and risk factors:

The cause of rheumatoid arthritis (RA) is unknown, but infectious, genetic, and endocrine factors may play a role. The disease can occur at any age, but the peak incidence of disease onset is between the ages of 25 and 55. Women are affected 3 times more often than men. The incidence increases with age. Approximately 3% of the population is affected. The course and the severity of the illness can vary considerably.

The onset of the disease is usually slow, with fatigue, loss of appetite, weakness, and vague muscular symptoms. Eventually, joint pain appears, with warmth, swelling, tenderness, and stiffness after inactivity of the joint.

The disease usually only involves a couple of joints initially, but slowly progresses into many other joints. At first, rheumatoid arthritis affects the synovium, which becomes inflamed and secretes more fluid. Later, the cartilage becomes involved and becomes rough and pitted.

The joints usually become affected in a symmetrical pattern, affecting both sides of the body equally. The hands, wrists, elbows, shoulders, knees and ankles are the most frequently affected. Characteristic deformities result from cartilage destruction and destruction of the supporting tissues around the bones. Occasionally, the hips, jaw and neck may be affected.

Other features of the disease not involving the joints may occur. Rheumatoid nodules are painless, hard round or oval masses (aggregations of cells) that appear under the skin, usually on pressure points such as the elbow or Achilles tendon. These are present in about a quarter of cases. On occasion, they appear in the eye where they sometimes cause inflammation. If they occur in the lungs, inflammation of the lining of the lung (pleurisy) may occur as well as a shortness of breath.

Anemia may occur due to failure of the bone marrow to produce enough new red cells to make up for the lost ones. Iron supplements will not help this condition.

Muscle weakness and atrophy may occur. If the heart becomes weakened, congestive heart failure may result.

Rheumatoid vasculitis (inflammation of the blood vessels) is a serious complication of RA and can be life threatening. It can lead to skin ulcerations, bleeding intestinal ulcers and neuropathies. Skin rashes, Raynaud's phenomenon, and massive hemorrhage may also result from vasculitis.