Systemic lupus erythematosus

Alternative names:

disseminated lupus erythematosus; lupus; lupus erythematosus; SLE

Definition:

A chronic inflammatory autoimmune disorder that may affect many organ systems including the skin, joints, and internal organs. See also lupus anticoagulant.

Causes, incidence, and risk factors:

Normally the immune system controls the body's defenses against infection. In systemic lupus erythematosus (SLE) and other autoimmune diseases, these defenses are turned against the body when antibodies are produced against its own cells. These antibodies fight against the body's blood cells, organs, and tissues, causing chronic diseases. The mechanism or cause of autoimmune diseases is not fully known.

The disease affects 8 times as many women as men. It may occur at any age, but appears mostly in people between the ages of 10 and 50 years. SLE may also be caused by certain drugs. When this occurs, it is known as drug-induced lupus erythematosus and is usually reversible when the medication is stopped.

The course of the disease may vary from a mild episodic illness to a severe fatal disease. Symptoms also vary widely with the individual and are characterized by remissions and exacerbation. At its onset, only 1 organ system may be involved. Additional organs may become involved later. The following organ system manifestations may be seen, but other manifestations are possible.

Musculoskeletal
Almost all people with SLE have joint pain and most develop arthritis. Frequently affected joints are the fingers, hands, wrists, and knees. Death of bone tissue can occur in the hips and shoulders and is frequently a cause of pain in those areas.

Skin
A malar "butterfly" rash over the cheeks and bridge of the nose affects about half of those with SLE. The rash is usually worsened by sunlight. A more diffuse rash may appear on other body parts that are exposed to the sun. Other skin lesions or nodules can occur.

Kidney
Most people with SLE have some deposits of protein within the cells (glomeruli) of the kidney; however, only 50% have lupus nephritis as defined by persistent inflammation in the kidney. They may eventually develop renal failure and require dialysis or kidney transplantation.

Nervous system
Neurologic disorders can affect up to 25% of those with SLE. Mild mental dysfunction is the most common symptom, but any area of the brain, spinal cord, or nervous system can be affected. Seizures, psychosis, organic brain syndrome, and headaches are some of the varied nervous system disorders that can occur.

Blood
Blood disorders can affect up to 85% of those with SLE. Venous or arterial blood clots can form and are associated with strokes and pulmonary embolism. Often platelets are decreased, or antibodies are formed against blood clotting factors, which may cause significant bleeding (see Lupus anticoagulant). Anemia of chronic disease often develops at some point in the course of the disease.

Heart
Inflammation of various parts of the heart may occur as pericarditis, endocarditis, or myocarditis. Chest pain and arrhythmia's may result from these conditions.

Lungs
Pleurisy, an inflammation of the lining of the lung, and pleural effusions, a fluid collection between the lung and its lining can occur as a result of SLE or infection. Chest pain and shortness of breath are frequently results of these disorders.

The incidence is 4 out of 10,000 people. African Americans and Asians are affected more often than other races.