Drug-induced MPO-ANCA-positive necrotizing crescentic glomerulonephritis preceded by granulomatous hepatitis

Abstract

A 67-year-old man being treated with allopurinol, furosemide, digoxin, and tamocapril for congestive heart failure and paroxysmal atrial fibrillation was admitted to our hospital because of intermittent fever, general fatigue, and liver dysfunction. On admission, myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) was positive, and the titer was high. Discontinuation of all four drugs led to improvement of the symptoms, but the patient's renal function deteriorated. Liver biopsy showed granulomatous hepatitis (GH), and renal biopsy findings led to a diagnosis of pauci-immune necrotizing crescentic glomerulonephritis (CGN). The patient's renal function spontaneously improved without immunosuppressive therapy, and the MPO-ANCA titer decreased. We speculate that some common pathway induced by the drugs, possibly allopurinol, led to the two different clinical diseases, GH and CGN.