Lupus (Systemic Lupus Erythematosus)

What Is It?

Lupus is thought to develop when your body's immune system mistakenly attack the body's own tissues rather than protecting them from outside invaders. Immune proteins called autoantibodies attack many different parts of the body, causing inflammation and tissue damage in many parts of the body, including the joints, skin, kidney, nervous system (brain, spinal cord and nerves), blood, heart, lungs, digestive system and eyes. Autoantibodies also can attach themselves to body chemicals, forming abnormal molecules called immune complexes that trigger additional inflammation and injury when they are deposited in various organs and tissues.

The exact cause of lupus remains a mystery, although scientists are investigating many different possibilities and believe several factors may play a role in the development of the disease. Since 90% of all lupus patients are women, usually of childbearing age, researchers think hormones may be involved. Lupus tends to run in families, so genetic factors may play a role. There is some evidence that the illness may be more common in people of African, Native American, West Indian and Chinese descent. Some researchers think lupus may be triggered by a virus or another type of infection in people who are genetically susceptible to the disease.

Lupus is relatively rare, affecting less than one in 2,000 people. The scientific name of the disease is systemic lupus erythematosus, or SLE.

Symptoms

In some people, lupus causes only mild illness, but in others it leads to potentially deadly complications. Symptoms tend to come and go. Periods of intensified symptoms are called flares and periods when symptoms disappear are called remissions. Flares can be triggered by many different factors, including sun exposure, infection, medication and possibly pregnancy, but often they occur for no apparent reason.

Lupus has the potential to affect many different parts of the body, so it can cause a wide range of symptoms including:

• Malaise (a general sick feeling)

• Fever

• Loss of appetite

• Weight loss

• Muscle and joint pain, with pain and swelling of the joints

• A butterfly-shaped rash on the cheeks and bridge of the nose, called a malar rash

• Skin photosensitivity (a more widespread rash and flu-like symptoms after exposure to sunlight)

• Hair loss

• A "discoid" rash, which appears as firm, round red plaques with raised borders

• Painful ulcers in the mouth, nose and genital areas

Other possible symptoms of lupus include:

• Neurological symptoms (headaches, seizures, trouble thinking or stroke)

• Psychiatric symptoms, including psychosis, in which hallucinations occur

• Heart problems (abnormal heart rhythms, heart failure, inflammation of the heart muscle or lining)

• Lung symptoms, especially pleurisy, which causes painful breathing

• Loss of vision

• Pain or swelling in an extremity due to thrombosis (abnormal blood clots)

Some people develop a form of lupus that involves only the skin, called cutaneous lupus or discoid lupus erythematosus. Another form of lupus follows exposure to certain drugs (drug-induced lupus) including procainamide and hydralazine. While drug-induced lupus may cause rash, arthritis and fever that appear similar to the systemic form of lupus, it tends to be milder.

Diagnosis

Your doctor will begin by reviewing your symptoms, your medical history and your exposure to factors that can trigger lupus flares. Next, he or she will examine you, looking for skin rashes on your face or on sun-exposed skin, tenderness or swelling of the joints and ulcers inside your mouth or nose. Your doctor will listen to your heart and lungs with a stethoscope, checking for signs of inflammation of the membrane covering the heart (pericarditis) or inflammation of the membranes covering the lungs (pleuritis).

If your doctor suspects you have lupus, he or she will order a blood test to look for a type of antibody, called the antinuclear antibody (ANA), that almost all people with lupus have in their blood. However, since the ANA test can sometimes be positive in people who do not have lupus, your doctor may order follow-up blood tests to look for other types of antibodies. Lupus cannot be diagnosed only on the basis of the ANA test.

Your doctor may evaluate your condition using the criteria established by the American College of Rheumatology. Your doctor may diagnose lupus even if you don't meet all of these criteria, which were developed for research studies. If you have had 4 of the 11 lupus criteria at some time during your illness, even if fewer than four are active at the time of diagnosis, the diagnosis is more certain and you may be eligible for entry into a research study of lupus.

The lupus criteria include the following:

• Malar rash

• Discoid rash

• Photosensitivity

• Ulcers in the mouth or nose

• Arthritis

• Pericarditis, confirmed by physical exam or electrocardiogram (EKG), or pleuritis, confirmed by physical findings or chest X-ray

• Kidney disorder, confirmed by finding high levels of protein in the urine or other specific urine abnormalities, especially red cells suggesting inflammation in the kidney

• Neurological disorder, including seizures or psychosis (a serious psychiatric illness)

• Blood disorder, including evidence of red blood cell destruction (hemolytic anemia), low white blood cells (leukopenia) or low platelets (thrombocytopenia)

• Immune disorder – This is established by the finding of certain antibodies in the blood, which may include a positive anti-ds-DNA test, a positive anti-Smith antibody test, a positive test for syphilis even though you don't have syphilis or a positive antiphospholipid antibody test (an antibody associated with miscarriage or blood clots).

• A positive ANA test result

Other tests that may be done to help diagnose lupus include:

• Erythrocyte sedimentation rate (ESR), a blood test that indicates the presence of inflammation

• A blood test to check levels of proteins involved in immune function

• A skin or kidney biopsy (taking a small tissue sample for laboratory examination)

• Additional blood tests for autoantibodies