Medicinal lupus is a reversible lupus–like syndrome caused by taking medications. Clinical manifestations of medicinal lupus are similar to SLE and include fever, arthralgia, myalgia, polyarthritis, pleurisy, pneumonitis, hepatomegaly, glomerulonephritis. The diagnosis is based on characteristic laboratory criteria (determination of antinuclear factor, antinuclear antibodies, LE cells in the blood) and the relationship of symptoms with the intake of certain medications. Usually, the manifestations of medicinal lupus disappear after the withdrawal of a causally significant drug; in severe cases, corticosteroids are prescribed.
Meaning
Medicinal lupus (medicinal lupus syndrome) is a symptom complex caused by the side effect of medications and regressing after their withdrawal. Medicinal lupus is similar in its clinical manifestations and immunobiological mechanisms to systemic lupus erythematosus. In rheumatology, medicinal lupus is diagnosed about 10 times less often than idiopathic SLE. In most cases, drug-induced lupus-like syndrome develops in patients over the age of 50 years, with almost the same frequency in men and women.
Causes
The development of medicinal lupus can be provoked by prolonged use or high dosages of a large range of medications. Medications with a known side effect include antihypertensive (methyldopa, hydralazine, atenolol), antiarrhythmic (novocainamide), anti-tuberculosis (isoniazid), anticonvulsants (hydantoin, phenytoin), sulfonamides and antibiotics (penicillin, tetracycline), neuroleptics (chlorpromazine), lithium salts, gold and other drugs. Most often, drug lupus occurs in patients suffering from hypertension, arrhythmia, tuberculosis, epilepsy, rheumatoid arthritis, infectious diseases and taking these drugs. Lupus-like syndrome may develop in women who use oral contraceptives for a long time.
The pathogenesis of medicinal lupus is associated with the ability of these drugs to cause the formation of antinuclear antibodies (ANA) in the body. Genetic determination plays an important role in predisposition to pathology, namely, the acetylating phenotype of the patient. Slow acetylation of these drugs by liver enzymes is accompanied by the production of higher AHA titers and more frequent development of medicinal lupus. However, in patients with lupus syndrome induced by novocainamide or hydralazine, a slow type of acetylation is detected.
In general, the probability of developing drug lupus depends on the dose of the drug and the duration of pharmacotherapy. With prolonged use of the drug, 10-30% of patients with antinuclear antibodies in the blood serum develop lupus-like syndrome.
Symptoms
In the clinic of medicinal lupus, general manifestations, articular and cardio-pulmonal syndromes prevail. The disease can manifest acutely or gradually with such nonspecific symptoms as malaise, myalgia, fever, slight weight loss. 80% of patients are concerned about arthralgia, less often – polyarthritis. Patients taking antiarrhythmic drugs (procainamide) have serositis (exudative pleurisy, pericarditis), cardiac tamponade, pneumonitis, aseptic infiltrates in the lungs. In some cases, the development of lymphadenopathy, hepatomegaly, the appearance of erythematous rashes on the skin is possible.
Unlike idiopathic systemic lupus erythematosus, with drug-induced syndrome, butterfly-shaped erythema on the cheeks, ulcerative stomatitis, Raynaud’s syndrome, alopecia, nephrotic syndrome, neurological and mental disorders (convulsive syndrome, psychoses) are rare. At the same time, the development of glomerulonephritis is characteristic of medicinal lupus caused by taking apressin.
Diagnostics
From the moment of the first clinical symptoms of medicinal lupus to the diagnosis, it often takes from several months to several years. During this time, patients can unsuccessfully be examined by a pulmonologist, cardiologist, rheumatologist about individual manifestations of the syndrome. Correct diagnosis is possible with a comprehensive assessment of clinical symptoms, comparing the signs of the disease with taking certain medications, conducting immunological tests.
The most specific laboratory criteria indicating medicinal lupus are the presence in the blood of antinuclear antibodies (antibodies to histones), antinuclear factor, antibodies to single-chiral DNA, LE cells, and a decrease in complement levels. Less specific for lupus syndrome, but highly specific for SLE, are antibodies to ds DNA, anti-Ro/SS-A, At to Sm-antigen, anti-La/SS-B. Differential diagnosis of medicinal lupus should be carried out with idiopathic SLE, malignant tumors of the lungs and mediastinum.
Treatment
The withdrawal of the drug that caused the drug lupus leads to a gradual regression of clinical and laboratory signs of the syndrome. The disappearance of clinical symptoms usually occurs within a few days or weeks after discontinuation of the drug. Antinuclear antibodies disappear more slowly – within a few months (sometimes up to 1 year or longer). In order to relieve the articular syndrome, nonsteroidal anti-inflammatory drugs may be prescribed. In severe course of drug lupus, prolonged persistence of clinical symptoms, the appointment of glucocorticoids is justified.
In order to avoid the development of medicinal lupus, medications should not be taken spontaneously and uncontrollably; the appointment of pharmacological agents should be justified and agreed with the attending physician. To prevent the recurrence of lupus syndrome, an adequate replacement of a causally significant drug with an alternative drug is necessary.