Diffuse alveolar hemorrhage and pulmonary capillaritis due to propylthiouracil

Propylthiouracil (PTU) has recently been observed to be associated with ant ineutrophil cytoplasmic antibody (ANCA)-positive small vessel vasculitis, r esulting in crescentic glomerulonephritis and, infrequently, diffuse alveol ar hemorrhage (DAH). We describe a case of a 23-year-old pregnant woman who developed a perinuclear ANCA and antimyeloperoxidase-positive small vessel vasculitis manifesting as DAH and crescentic glomerulonephritis after she began taking PTU. An open lung biopsy was consistent with pulmonary capilla ritis. She responded to corticosteroid therapy and discontinuation of PTU. DAH can be caused by pulmonary capillaritis, bland hemorrhage, or diffuse a lveolar damage. To our knowledge, this represents the first documentation o f an underlying pulmonary capillaritis in a case of PTU-induced DAH.