Rheumatoid Arthritis

Tests overview

RA is difficult to diagnose in its early stages, when the joints may appear normal. Initially, the diagnosis is made by ruling out other possible causes for the symptoms. The doctor will take a medical history and conduct a physical examination similar to the one used to diagnose osteoarthritis. The presence of RA can be confirmed later with X-rays and laboratory tests.

Certainly, the finding of multiple red, swollen joints that are warm to the touch is strongly suggestive of RA, particularly if the same joints are involved on both sides of the body. However, these signs are present only during the active stages of the disease and may not be detectable in joints such as the hip that are deeply buried in the body.

This section has more on:

• Medical history
• Laboratory tests
• Prognosis

Medical history

For the best treatment, patients must honestly answer their doctors' questions about pain, disability, limitations in activity, fatigue, and other symptoms. In addition, people should not hesitate to mention any symptoms that the doctor did not ask about. Although this advice may seem obvious, a recent study found that women with RA tended to downplay the severity of their symptoms when consulting doctors. Since doctors rely on people's reports of pain, stiffness, disability, and other symptoms in choosing among therapeutic options, stoic responses may adversely affect the quality of treatment.

Laboratory tests

The diagnosis of RA can be made more certain by documenting the presence of synovitis--inflammation of the synovial membrane. Synovitis can be detected by withdrawing a small amount of fluid. Other causes of synovitis must still be considered, however. Although X-rays of affected joints are not useful during the early stages of RA, those taken more than six months after the onset of active disease can show the characteristic narrowing of the joint space and the bony erosions that point to a diagnosis of RA.

A blood test to check for the presence of rheumatoid factor is also useful. However, this test is not definitive because elevated levels of rheumatoid factor can be found in people with other autoimmune diseases, as well as a number of unrelated disorders. Other common blood abnormalities indicative of RA are mild anemia, an elevated sedimentation rate (a nonspecific sign of inflammation), and a low white blood cell count.

Prognosis

About 10 percent of people diagnosed with RA experience long-term remission within one year. An additional 40 percent to 65 percent go into remission within two years. In these two groups of patients, rheumatoid factor levels often are low or absent, and symptoms are relatively mild, even when the disease is active. The prognosis is much worse if the disease remains active for more than two years. Such patients have a far greater chance of significant joint deformity.

If the disease progresses for months or years, affected joints eventually become deformed and their range of motion is increasingly limited. Other possible side effects are carpal tunnel syndrome (pain, numbness, or tingling in the hand) and dryness of the eyes, mouth, and other mucous membranes. Less frequently, people may experience more serious systemic problems (problems affecting other sites in the body). These include an enlarged spleen and inflammation of the heart, the membrane covering the heart (pericarditis), the membranes surrounding the lungs (pleurisy), and the outer layers of the eyes (which can lead to blindness).

People with RA have a shorter life span than the general population, largely owing to an increased risk of heart disease. For this reason, people with RA need to take extra steps to prevent heart disease.