The study objective is to demonstrate the difficulty of differential diagnosis in pulmonary-renal syndrome using a clinical case as an example.Materials and methods. Male patient A., 68 years old, retired, was hospitalized at the N.I. Pirogov City Clinical Hospital № 1 in December of 2017 with complaints of inefficient cough, fever of 39 °С, weakness, apnea, weight loss up 10 kg in 3 months. Examination revealed skin and mucosa paleness, calf edema, heart beat of 102 bpm, normal rhythm, arterial pressure 130/80 mm Hg, respiratory rate 22 breaths per min. Auscultation revealed harsh respiration in the lungs, weakened in the lower parts, fine moist rales. Anemia (hemoglobin – 53 g/l, erythrocytes – 1.85 × 1012/l, serum iron – 3.1 µmol/l), elevated urea up to 41.4 mmol/l, creatinine up to 843.1 µmol/l (glomerular filtration rate – 6 ml/min/1.73 m2), leukocytes up to 12.5 × 109/l, С-reactive protein up to 124.96 mg/l were diagnosed. Clinical urine analysis showed proteinuria 0.47 g/l. Computed tomography of the chest revealed pronounced infiltrative changes in tissues of both lungs, more on the right, alveolitis, bronchiolitis in the middle lobe on the right, 5th segment on the left. Lymphadenopathy mediastinal was diagnosed. After examination (multiple bacteriological blood, sputum tests, interferon-gamma release assay, echocardiography, bronchoalveolar lavage, sterna puncture, esophagogastroduodenoscopy, colonoscopy, etc.), oncological pathology, tuberculosis of the lungs, sepsis, infections endocarditis and other infectious pathologies were excluded. Antibacterial courses prescribed earlier were ineffective. Immunological blood test revealed high titers (1:1280) of antineutrophil cytoplasmic antibodies (ANCA) with perinuclear fluorescence type (myeloperoxidase specificity), negative antibodies to glomerular basal membrane which allowed to diagnose ANCA-associated vasculitis.Results. Considering the data of clinical, lab, and instrumental examination, the patient was diagnosed with microscopic polyangiitis, ANCA-associated, affecting the lungs (disseminated interstitial lung disease with bronchiolitis) and kidneys (rapidly progressive glomerulonephritis), intrathoracic lymphadenopathy, activity grade III (BVAS index – 23 points). Grade II respiratory failure. Chronic kidney disease 5D (glomerular filtration rate – 6 ml/min/1.73 m2). Grade II arterial hypertension, risk 4. Grade II pulmonary hypertension. Chronic heart failure 2А, functional class IV. Mixed anemia (iron-deficient, chronic disease), severe. Disseminated polyposis of the colon (hyperplastic type). At the hospital, antibacterial drugs (cefoperazone sulbactam), antifungal (fluticasone) were administered, anemia was corrected (iron-containing drugs and erythropoietin, hemotransfusion), hemodialysis. Cyclophosphane 400 mg was administered intravenously, a week later – 800 mg. Methylprednisolone (60 mg/day), co-trimoxazole (480 mg 3 times a week) were prescribed. A pronounced improvement was observed due to the therapy: body temperature normalization, decreased apnea, cough, weakness, increased appetite. The patient was discharged with recommendation for continuation of cytostatic therapy per the regimen and prescription for programmed hemodialysis at the place of residence.Conclusion.This clinical case demonstrates a necessity of considering ANCA-associated vasculitis during differential diagnosis of pulmonary-renal syndrome. Timely diagnosis and active cytostatic therapy play a principal role in treatment and promote deceleration of disease progression and improve prognosis.
