What is Lupus? Systemic Lupus Erythematosus (SLE)

Lupus facial rash in a typical wolf-like distr...Image via Wikipedia
Systemic Lupus Erythematosus (SLE) a chronic inflammatory disease that can affect various parts of the body, especially the skin, joints, blood, and kidneys. The body's immune system normally makes proteins called antibodies to protect the body against viruses, bacteria, and other foreign materials. These foreign materials are called antigens. In an autoimmune disorder such as lupus, the immune system loses its ability to tell the difference between foreign substances (antigens) and its own cells and tissues. The immune system then makes antibodies directed against "self." These antibodies, called "auto-antibodies," react with the "self" antigens to form immune complexes. The immune complexes build up in the tissues and can cause inflammation, injury to tissues, and pain. The disease whose severity spans a spectrum, with some lucky patients having milder symptoms without organ involvement (such as malar rash, canker sores, joint pain without swelling) and other patients having severe organ involvement (such as found in the kidneys and brain). Physicians who treat SLE will often describe the disease as mild, moderate or severe, usually on the basis of the severity of the organ involvement and the potential for permanent organ damage. Generally, no two people with systemic lupus will have identical symptoms. Systemic lupus may include periods in which few, if any, symptoms are evident ("remission") and other times when the disease becomes more active ("flare"). Most often when people mention "lupus," they are referring to the systemic form of the disease; however, there are two other types of lupus: discoid and drug-induced. Discoid (cutaneous) lupus is always limited to the skin. It is identified by a rash that may appear on the face, neck, and scalp. Drug-induced lupus occurs after the use of certain prescribed drugs. The symptoms of drug-induced lupus are similar to those of systemic lupus. The drugs most commonly connected with drug-induced lupus are hydralazine (used to treat high blood pressure or hypertension) and procainamide (used to treat irregular heart rhythms). The symptoms usually fade when the medications are discontinued. For most people, lupus is a mild disease but, it may cause serious and even life-threatening problems. More than 16,000 Americans develop lupus each year. It is estimated that 1.5 million Americans have been diagnosed with lupus. Women develop the disease at least ten times more often; although men and even children are affected. Africans Americans have a three-fold higher frequency of lupus than do European Americans, and lupus in African Americans is, on average, more severe. Genes causing lupus in African Americans generally different from those causing lupus in European Americans.
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Lupus Diagnosis

Common signs and symptoms of systemic lupus er...Image via Wikipedia
Some physicians make a diagnosis on the basis of the 11 ACR classification criteria (see below). The criteria, however, were established mainly for use in scientific research (i.e., inclusion in randomized controlled trials), and patients may have lupus but never meet the full criteria. Click for Table 1982 Revised ARA Criteria for Classification of Systemic Lupus Erythematosus

ACR classification criteria


  1. Serositis: Pleuritis (inflammation of the membrane around the lungs) or pericarditis (inflammation of the membrane around the heart);
  2. Oral ulcers includes oral or nasopharyngeal ulcers.
  3. Arthritis: nonerosive arthritis of two or more peripheral joints, with tenderness, swelling, or effusion;
  4. Photosensitivity (exposure to ultraviolet light causes rash);
  5. Blood-hematologic disorder-hemolytic anemia (low red blood cell count) or leukopenia ((low white blood cell count); Also lymphopenia, thrombocytopenia or hypocomplementemia;
  6. Renal disorder: protein in urine or cellular casts
  7. seen in urine under a microscope;
  8. Antinuclearantibody test positive;
  9. Immunologic disorder: Positive anti-Smith, anti-ds DNA, antiphospholipid antibody, and/or false
  10. positive serological test for syphilis; Presence of anti-ss DNA in 70% of patients (though also positive in patients with rheumatic disease and healthy persons.
  11. Neurologic disorder: Seizures or psychosis;
  12. Malar rash (rash on cheeks);
  13. Discoid rash (red, scaly patches on skin that cause scarring);

erythematosus chest rash
Discoid Rash

THE LUPUS DIAGNOSTIC TESTS: ANA: Antinuclear antibodies and other "Anti-"

The patient with SLE, or lupus is often first referred to a rheumatologist for diagnosis based on the result of a positive blood test for antinuclear antibodies (ANA). The ANA is the "sine qua non" of lupus, meaning that virtually every patient with SLE will have a positive ANA, yet the blood test is by no means "specific". This means that some 5% of the population may have a positive ANA but never develop lupus. In general, the higher the antibody titer value, the high the probability of SLE. A more specific blood test is the "anti-double stranded, or native, DNA". Finding this antibody in the patient's very genetic material makes the diagnoses of SLE more probable, and its presence may predict current or future involvement of the kidney. Perhaps the most specific antibody is "anti-Smith", names after the patient in whom it was originally found. This test is nearly 100% predictive of SLE if it is present, but it is only found in less than 20% of patients.

 

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