Systemic Lupus Erythematosus Health Article

Definition

SLE is one of many disorders of the immune system known as autoimmune diseases. In this type of disease, the immune system turns against parts of the body it is designed to protect. In persons with SLE, the immune system produces antibodies against healthy cells and tissues. These antibodies, called autoantibodies, contribute to the inflammation of various parts of the body.

The most common type of autoantibody that develops in persons with SLE is called antinuclear antibody, because it reacts with parts of a cell's nucleus. This leads to inflammation and damage to various body tissues. SLE can affect many parts of the body including the brain, heart, joints, kidneys, lungs, skin, and blood vessels. The course of SLE is characterized by periods of illness, or flares, and periods of wellness, or remission. .

Scope

SLE is 3 times more common in black women than in white women, and it is also more common in women of Hispanic, Asian, and Native American descent. Although SLE usually initially affects persons between the ages of 15 and 45 years, it can occur during childhood or later in life. In addition, SLE can run in families; however, the risk that a child or sibling of a patient will also have the disease is still quite low. It is difficult to estimate how many persons in the United States have SLE, because its symptoms vary widely, and its onset is often hard to pinpoint.

Etiology

SLE is a complex disease, and its cause is unknown. It is likely that a combination of genetic, environmental, and possibly hormonal factors work together to cause the disease. The fact that SLE can run in families indicates that its development has a genetic basis; however, no specific gene has been identified. Studies suggest that several different genes could be involved in determining a person's likelihood of developing the disease, which tissues and organs are affected, and the severity of disease. It is believed that genes alone do not determine who is affected by the disease. Contributing factors under study include sunlight, stress, certain drugs, and infectious agents such as viruses.

Symptoms

Each person with SLE has slightly different symptoms that can range from mild to severe and that can come and go over time. Some common symptoms include the following:

• painful or swollen joints;
• muscle pain;
• unexplained fever;
• red rashes, most commonly on the face (in particular, a characteristic rash known as a butterfly or malar rash can appear across the nose and cheeks);
• chest pain with deep breathing;
• unusual loss of hair;
• Raynaud's phenomenon;
• sensitivity to the sun (rashes can first develop or worsen with sun exposure);
• edema in the legs or around the eyes;
• mouth ulcers;
• lymphadenopathy; and.
• extreme fatigue.

In some persons with SLE, only one system of the body (eg, the skin or the joints) is affected. Other persons experience symptoms in many parts of their bodies. Examples of the manifestations of SLE in other body systems can include the following:

• renal system—nephritis;
• pulmonary system—pleuritis or pneumonia;
• central nervous system—headaches, dizziness, seizures, stroke, memory disturbances, vision problems, or changes in behavior;
• vascular system—vasculitis;
• hematologic system—anemia, leukopenia, thrombocytopenia, or clot formation; and.
• circulatory system—myocarditis, endocarditis, pericarditis, or atherosclerosis.

Diagnosis

Diagnosing lupus can be difficult and may take months or years. No single test can determine whether a person has SLE. Components of the diagnostic workup can include the following:

• medical history;
• physical examination;
• complete blood count;
• ESR (often elevated above normal range, especially during flares);
• urinalysis;
• blood chemistries;
• complement levels (often below normal range, especially during flares);
• antinuclear antibody testing;
• other autoantibody testing (anti-DNA, anti-Sm, anti-RNP, anti-Ro, anti-La);
• anticardiolipin antibody testing;
• skin biopsy; and.
• kidney biopsy.