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; 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 (RA) is that it varies a lot from person to person. In 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.

Scientists estimate that about 2.1 million people, or 1% of the U.S. adult population, have RA. Some recent studies suggest that the number of new cases of RA may actually be going down. Scientists are now investigating why this may be happening.

Rheumatoid arthritis occurs in all races and ethnic groups. Although the disease often begins in middle age and occurs with increased frequency in older people, children and young adults also develop it. It occurs in 2 to 3 times as many women as men. To try and explain this discrepancy, researchers are investigating the role of female and male hormones and other possible gender-based differences in immune responses.

Although RA 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.

Features of Rheumatoid Arthritis

• Tender, warm, swollen joints.
• Symmetrical pattern. For example, if one knee is affected, the other one is also.
• Joint inflammation often affecting the wrist and finger joints closest to the hand; other affected joints can include those of the neck, shoulders, elbows, hips, knees, ankles, and feet.
• Fatigue, occasional fever, a general sense of not feeling well (malaise).
• Pain and stiffness lasting for more than 30 minutes in the morning or after a long rest.
• Symptoms that can last for many years.
• Symptoms in other parts of the body besides the joints.
• Variability of symptoms among people with the disease.

Development and Progression of Rheumatoid Arthritis

In RA 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 RA. 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.

As RA progresses, the abnormal synovial cells 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. These effects lead to the pain and deformities often seen in RA. Doctors studying RA believe that damage to bones begins during the first year or two that a person has the disease, so early diagnosis and treatment are very important.

In other parts of the body: Some people also experience the effects of RA in places other than the joints. About 25% of RA patients develop bumps under the skin, called rheumatoid nodules, that often form close to the joints. Many people with RA develop anemia -- 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.

Searching For the Cause of Rheumatoid Arthritis

Genetic (inherited) factors: Investigators have found that certain genes that play a role in the immune system are associated with a tendency to develop RA. At the same time, some people with RA do not have these particular genes, and other people have these genes but never develop the disease. This suggests that a person's genetic makeup is an important part of the story but not the whole answer. It is clear, however, that more than one gene is involved in determining whether a person develops RA, and if so, how severe the disease will become.

Environmental factors: Many scientists think that something must occur to trigger the disease process in people whose genetic makeup makes them susceptible to RA. An infectious agent such as a virus or bacterium appears likely, but the exact agent is not yet known. This does not mean that RA is contagious: a person cannot "catch" it from someone else.

Other factors: Some scientists also think that a variety of hormonal factors may be involved. These hormones, or possibly deficiencies or changes in certain hormones, may promote the development of RA in a genetically susceptible person who has been exposed to a triggering agent from the environment.

Even though all the answers aren't known, one thing is certain: RA develops as a result of the interaction of many factors. Much research is going on now to understand these factors and how they work together.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.