Propylthiouracil-Induced Antineutrophil Cytoplasmic Antibodies-Associated Vasculitis with Renal and Lung Involvement.

Propylthiouracil (PTU)-induced antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is a rare and heterogeneous disease. Moreover, optimal treatment is still lacking. We described the case of a 44-year-old lady with underlying Graves' disease who had cough, blood-streaked sputum, and impaired renal function. A strongly positive anti-myeloperoxidase antibody (>200 U/mL) along with pauci-immune glomerulonephritis and pulmonary hemorrhage resulted in the diagnosis of PTU-induced AAV, given that the patient had been on PTU for 3 years. PTU withdrawal, therapeutic plasma exchanges, and oral cyclophosphamide provided favorable clinical and biochemical outcomes. She remained well on azathioprine 50 mg daily as maintenance therapy and clinically euthyroid with carbimazole 2.5 mg daily. The effective treatment for drug-induced ANCA vasculitis remains controversial, but rapid withdrawal of the offending medication should be the mainstay of treatment. In severe drug-induced ANCA vasculitis with pulmonary hemorrhage and/or life-threatening organ involvement such as kidney failure requiring dialysis, therapeutic plasma exchange with immunosuppressants is often required. In this case, we have shown that patient achieved remission after therapeutic plasma exchange with cyclophosphamide in the acute stage of treatment and remained symptom-free with azathioprine in the maintenance phase of treatment for 24 months.