Diagnosis of systemic lupus erythematosus
Systemic lupus erythematosus should be suspected, especially in young women, if there are symptoms associated with it. In the early stages of systemic lupus erythematosus, it may resemble other connective tissue diseases (or other pathologies), including RA, if the joint syndrome predominates. Systemic lupus erythematosus can resemble a mixed connective tissue disease, systemic scleroderma, rheumatoid polyarthritis, polymyositis or dermatomyositis. Infections that develop as a result of immunosuppressive therapy can also mimic manifestations of systemic lupus erythematosus.
Conducting laboratory tests allows differentiating systemic lupus erythematosus from other connective tissue diseases; this requires the determination of the antiserum antibody titer, the counting of white blood cells, the performance of a general urinalysis, the evaluation of renal and hepatic functions. Diagnosis of systemic lupus erythematosus is very likely if the patient has 4 or more criteria in any period of the disease, but is not excluded when only fewer than 4 criteria are found. If the diagnosis is suspected, but not proven, additional studies should be performed on the presence of autoantibodies. In addition, the verification of dia
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Criteria for diagnosis of systemic lupus erythematosus 1
For the diagnosis of systemic lupus erythematosus, a minimum of 4 of the following signs
- Rashes on the face in the form of "butterfly wings"
- Discoid rashes
- Ulceration of the oral cavity
- Renal damage
- Leukopenia (<4000 μl), lymphopenia (<1500 μl), hemolytic anemia or thrombocytopenia (<100,000 μl)
- Neurological disorders
- Detection of antibodies to DNA, Sm-antigen, false positive reaction of Wasserman
- Increased antinuclear antibody titre
1 These 11 criteria are proposed by the American College of Rheumatology and are often used for diagnostic purposes. Although the patient's minimum of 4 criteria is not completely specific for the diagnosis of systemic lupus erythematosus, they help to recognize the manifestations of the disease.
For the diagnosis of systemic lupus erythematosus may require repeated studies in months and even years. The best test for the diagnosis of systemic lupus erythematosus is the immunofluorescence determination of antinuclear antibodies; a positive result (usually high titers,> 1:80) is determined in more than 98% of patients. Nevertheless, this test can be false-positive in patients with RA, other connective tissue diseases, malignant tumors and even in 1% of healthy individuals. Such drugs as hydralazine, procainamide, beta-blockers, antagonists of tumor necrosis factor-alpha (TNF-a) can cause the development of lupus-like syndromes and lead to false positive laboratory results; but in this case, with the abolition of these drugs, seroconversion is noted. When antinuclear antibodies are detected, a study should be made of autoantibodies to the DNA double helix, high titres of which are specific for systemic lupus erythematosus.
Other studies for the presence of antinuclear and anti-cytoplasmic antibodies [eg, Ro (SSA), La (SSB), Sm, RNP, Jo-1] should be carried out in cases where the diagnosis of systemic lupus erythematosus remains unclear. Ro antigen is predominantly in the cytoplasm; Anti-Ro antibodies are sometimes found in patients who do not demonstrate the production of antinuclear autoantibodies suffering from chronic cutaneous lupus erythematosus. They are also characteristic of lupus in newborns and children with congenital heart block. Anti-Sm are highly specific for systemic lupus erythematosus, but, like autoantibodies to the double helix DNA, are characterized by low sensitivity.
Leukopenia is a frequent manifestation of the disease, in its active phase, the development of lymphopenia is possible. Hemolytic anemia can also be observed. Thrombocytopenia in systemic lupus erythematosus is difficult, and sometimes impossible to differentiate from idiopathic thrombocytopenic purpura, except for patients with antinuclear antibodies. In 5-10% of patients with systemic lupus erythematosus, false positive serological responses to syphilis are noted. It is believed that this is due to lupus anticoagulant and prolongation of prothrombin time. Therefore, the pathological values of one or more of these indicators indicate the presence of antiphospholipid antibodies (for example, antibodies to cardiolipin) that can be detected by an enzyme immunoassay. The detection of antibodies to beta 2 -glycoprotein I is probably more informative. The presence of antiphospholipid antibodies allows predicting the development of arterial and venous thromboses, thrombocytopenia and, in pregnancy, spontaneous abortion and intrauterine fetal death.
Other studies help evaluate the nature of the course of the disease and the need for specific therapy. Concentration of complement components (C3, C4) in serum often decreases in the active phase of the disease, and in particular in patients with active nephritis. The increase in ESR always indicates an active phase of the disease. In contrast, the determination of the concentration of C-reactive protein is not necessary: it can be extremely low in systemic lupus erythematosus, even with an ESR value of more than 100 mm / h.
Evaluation of involvement in the kidney process begins with a general analysis of urine. Erythrocytes and hyaline cylinders suggest the presence of active jade. Urine tests should be performed periodically, at intervals of approximately 6 months, even in the remission phase of the disease. Nevertheless, the results of urinalysis, even with repeated analyzes, can be normal, despite kidney damage, verified by a histological examination of the biopsy material. Conducting a kidney biopsy is usually not required for the diagnosis of systemic lupus erythematosus, but helps assess their condition (eg, acute inflammation or post-inflammatory sclerosis) and choose adequate therapy. In patients with chronic renal failure and severe glomerulosclerosis, the advisability of conducting aggressive immunosuppressive therapy is questionable.
Diagnosis of systemic lupus erythematosus
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