Systemic Lupus Erythematosus Health Article

Definition

Systemic lupus erythematosus (also called lupus or SLE) is a disease in which a person's immune system attacks and injures the body's own organs and tissues. Almost every system of the body can be affected.

Description

The body's immune system is a network of cells and tissues responsible for clearing the body of invading organisms, like bacteria, viruses, and fungi. Antibodies are special immune cells that recognize these invaders, and begin a chain of events to destroy them. In an autoimmune disorder like SLE, a person's antibodies begin to identify the body's own tissues as foreign. Cells and chemicals of the immune system damage the tissues of the body. The reaction that occurs in tissue is called inflammation. Inflammation includes swelling, redness, increased blood flow, and tissue destruction.

In SLE, some of the common antibodies that normally fight diseases are thought to be out of control. These include antinuclear antibodies, which are directed against the cell structure that contains genetic material (the nucleus), and anti-DNA antibodies, which are directed against genetic material (DNA).

SLE can occur in both males and females of all ages, but 90% of patients are women. The majority of these women are in their childbearing years. African Americans are more likely than Caucasians to develop SLE.

Occasionally, such medications as hydralazine and procainamide can cause symptoms very similar to SLE. This condition is called drug-induced lupus. Drug-induced lupus usually disappears after the patient stops taking the particular medication.

Causes & symptoms

The cause of SLE is unknown. Because the vast majority of patients are women, some research is being done to determine what (if any) link the disease has to female hormones. Susceptibility to SLE is known to have a genetic basis, although more than one gene is believed to be involved in disease development. As of 2002, notable progress has been made in narrowing the location of these genes. Because SLE patients may suddenly have worse symptoms (called a flare) after exposure to sunlight, such foods as alfalfa sprouts, and certain medications, environmental factors may also be at work.

The severity of symptoms varies over time, with periods of mild or no symptoms followed by a flare. During a flare, symptoms increase in severity and new organ systems may become affected.

Many SLE patients have fevers, fatigue, muscle pain, weakness, decreased appetite, and weight loss. The spleen and lymph nodes are often swollen and enlarged. Recurrent infections, particularly those caused by bacteria, are common in patients with SLE. The development of other symptoms in SLE varies depending on the organs affected.

• Joints. Joint pain and problems, including arthritis, are very common. About 90% of all SLE patients have these types of problems.
• Skin. A number of skin rashes may occur, including a red butterfly-shaped rash that spreads across the face. The "wings" of the butterfly appear across the cheekbones, and the "body" appears across the bridge of the nose. A discoid, or coin-shaped, rash causes red scaly bumps on the cheeks, nose, scalp, ears, chest, back, and the tops of the arms and legs. The roof of the mouth may develop sore, irritated pits (ulcers). Hair loss is common. SLE patients tend to be very easily sunburned (photosensitive).
• Lungs. Inflammation of the tissues that cover the lungs and line the chest cavity causes pleuritis, with fluid accumulating in the lungs. The patient frequently experiences coughing and shortness of breath.
• Heart and circulatory system. Inflammation of the tissue surrounding the heart causes pericarditis; inflammation of the heart itself causes myocarditis. These heart problems may result in abnormal heartbeat (arrhythmias), difficulty pumping the blood strongly enough (heart failure), or even sudden death. Blood clots often form in the blood vessels and may lead to complications.

• Nervous system. Headaches, seizures, changes in personality, and confused thinking (psychosis) may occur. The molecular mechanism responsible for brain dysfunction in lupus was identified in 2001.
• Kidneys. The kidneys may suffer significant destruction, with serious life-threatening effects. They may become unable to adequately filter the blood, leading to kidney failure.
• Gastrointestinal system. Patients may experience nausea, vomiting, diarrhea, and abdominal pain. The lining of the abdomen may become inflamed (peritonitis).
• Eyes. The eyes may become red, sore, and dry. Inflammation of one of the nerves responsible for vision may cause vision problems, and blindness can result from inflammation of the blood vessels (vasculitis) that serve the retina.