Systemic Lupus Erythematosus (SLE)
Systemic Lupus Erythematosus is an inflammatory multi-system disease of unknown etiology. It is recognized worldwide and clearly more prevalent in women, especially in their reproductive years.
This effect of age and sex on incidence and prevalence rates of SLE suggests a role for hormonal factors in its pathogenesis. In the USA, SLE is three times more common among blacks than whites.
Genetic factors have long been considered to have a role in the formation of SLE. There are observations of a higher prevalence of SLE among twins.
SLE is a chronic inflammatory disease with variable clinical courses. The clinical picture of SLE can change over time, in terms of both disease activity and organ involvement. The pathogenesis of SLE is complex and parallels the wide variation in clinical symptoms. No single mechanism of action applies to all cases and the initial triggering events remain largely unknown.
SLE can affect the skin, joints, kidneys, lungs, nervous system, serous membranes and/or other organs of the body. Immunologic abnormalities, especially the production of a number of antinuclear antibodies, are another prominent feature of the disease. The clinical course may be characterized by periods of remissions and chronic or acute relapses.
The criteria for the classification of SLE require 4 of the following 11 items:
Malar rash - Fixed erythema, flat or raised, over the malar eminences, sparing the nasolabial folds
Discoid rash - Erythematous raised patches with adherent keratotic scaling and follicular plugging; possible atrophic scarring in older lesions
Photosensitivity - Skin rash as a result of unusual reaction to sunlight, by patient’s history or physician observation
Oral ulcers - Oral or nasopharyngeal ulceration, usually painless, observed by a physician
Non-erosive arthritis - Involving two or more peripheral joints, characterized by tenderness, swelling or effusion
Serositis - Pleuritis – convincing history of pleuritic pain or rub or evidence of pericardial effusion, OR Pericarditis – documented electrocardiography or rub or evidence of pericardial effusion
Renal disorder - Persistent proteinuria of >0.5 g/d or 3+ if quantitative not performed, OR Cellular casts – red cell, hemoglobin, granular, tubular or mixed
Neurological disorders - Seizures – in the absence of offending drugs or metabolic derangement, OR Psychosis – in the absence of offending drugs or metabolic derangement
Hematologic abnormalities - Hemolytic anemia with reticulocytosis, OR Leukopenia – <4,000/mm3 on two occasions, OR Lymphopenia – <1,500/mm3 on two occasions, OR Thrombocytopenia – <100,000/mm3 in the absence of drugs
Immunologic abnormalities - Anti-DNA – antibody to native DNA in abnormal titer, OR Anti-Sm – presence of antibody to Sm nuclear antigen, OR Antiphospholipid antibodies – an abnormal IgG or IgM anticardiolipin antibodies or positive lupus anticoagulant, OR False positive test for >6 months, confirmed by Treponema pallidum immobilization or fluorescent treponemal test
Positive ANA - An abnormal titer of antinuclear antibody by immunofluorescence or an equivalent assay in any point in time in the absence of drug
Most patients with SLE have mild to moderate disease with chronic smoldering symptoms, punctuated by gradual or sudden increases in disease activity (flare-ups). The disease course in a smaller percentage of patients is characterized by alternating flare-ups and complete clinical remissions. Rarely, a patient has a single episode of active SLE followed by sustained remission.
The management of patients with SLE is decided on an individual basis, guided by the degree and severity of specific symptoms and organ involvement.
Preventive strategies for decreasing SLE flare-ups are recommended for most patients. These include:
Avoid ultraviolet light exposure not only through the use of sunscreens but by staying out of the sunlight or wearing protective clothing.
Avoid exercising to exhaustion. Extreme physical efforts are likely to trigger increased lupus activity.
Avoid infections. Many common respiratory infections can be prevented by frequent washing of the hands and other simple hygiene measures.
Pregnancy may entail a slightly increased risk of a lupus flare-up. Also, breast-feeding may increase the risk of a postpartum flare-up.