Consumer Information Center Rheumatoid Arthritis

Rheumatoid arthritis is an inflammatory disease that causes pain, swelling, stiffness, and loss of function in the joints. It has several special features that make it different from other kinds of arthritis. For example, rheumatoid arthritis generally occurs in a symmetrical pattern. This means that if one knee or hand is involved, the other one is also. The disease often affects the wrist joints and the finger joints closest to the hand. It can also affect other parts of the body besides the joints. In addition, people with the disease may have fatigue, occasional fever, and a general sense of not feeling well (malaise).

Another feature of rheumatoid arthritis is that it varies a lot from person to person. For some people, it lasts only a few months or a year or two and goes away without causing any noticeable damage. Other people have mild or moderate disease, with periods of worsening symptoms, called flares, and periods in which they feel better, called remissions. Still others have severe disease that is active most of the time, lasts for many years, and leads to serious joint damage and disability.

Although rheumatoid arthritis can have serious effects on a person’s life and well-being, current treatment strategies—including pain relief and other medications, a balance between rest and exercise, and patient education and support programs—allow most people with the disease to lead active and productive lives. In recent years, research has led to a new understanding of rheumatoid arthritis and has increased the likelihood that, in time, researchers can find ways to greatly reduce the impact of this disease.

The Joints

A normal joint (the place where two bones meet) is surrounded by a joint capsule that protects and supports it (see illustration). Cartilage covers and cushions the ends of the two bones. The joint capsule is lined with a type of tissue called synovium, which produces synovial fluid. This clear fluid lubricates and nourishes the cartilage and bones inside the joint capsule.

In rheumatoid arthritis, the immune system, for unknown reasons, attacks a person’s own cells inside the joint capsule. White blood cells that are part of the normal immune system travel to the synovium and cause a reaction. This reaction, or inflammation, is called synovitis, and it results in the warmth, redness, swelling, and pain that are typical symptoms of rheumatoid arthritis. During the inflammation process, the cells of the synovium grow and divide abnormally, making the normally thin synovium thick and resulting in a joint that is swollen and puffy to the touch (see illustration).

As rheumatoid arthritis progresses, these abnormal synovial cells begin to invade and destroy the cartilage and bone within the joint. The surrounding muscles, ligaments, and tendons that support and stabilize the joint become weak and unable to work normally. All of these effects lead to the pain and deformities often seen in rheumatoid arthritis. Doctors studying rheumatoid arthritis now believe that damage to bones begins during the first year or two that a person has the disease. This is one reason early diagnosis and treatment are so important in the management of rheumatoid arthritis.

A joint (the place where two bones meet) is surrounded by a capsule that protects and supports it. The joint capsule is lined with a type of tissue called synovium, which produces synovial fluid that lubricates and nourishes joint tissues. In rheumatoid arthritis, the synovium becomes inflamed, causing warmth, redness, swelling, and pain. As the disease progresses, abnormal synovial cells invade and erode, or destroy, cartilage and bone within the joint. Surrounding muscles, ligaments, and tendons become weakened. Rheumatoid arthritis can also cause more generalized bone loss that may lead to osteoporosis (fragile bones that are prone to fracture).

Other Parts of the Body

Some people also experience the effects of rheumatoid arthritis in places other than the joints. About one-quarter develop rheumatoid nodules. These are bumps under the skin that often form close to the joints. Many people with rheumatoid arthritis develop anemia, or a decrease in the normal number of red blood cells. Other effects, which occur less often, include neck pain and dry eyes and mouth. Very rarely, people may have inflammation of the blood vessels, the lining of the lungs, or the sac enclosing the heart.