Diffuse alveolar hemorrhage associated with antineutrophil cytoplasmic antibody levels in a pregnant woman taking propylthiouracil.

Propylthiouracil (PTU) is known to be a potential cause of antineutrophil cytoplasmic antibody (ANCA) positive small vessel vasculitis, resulting in glomerulonephritis and diffuse alveolar hemorrhage (DAH). Herein, we describe a 25-year-old pregnant woman who developed a perinulcear ANCA (p-ANCA) and myeloperoxidase ANCA (MPO-ANCA) positive DAH during PTU therapy. The patient improved after corticosteroid therapy and discontinuation of the PTU. Methimazole was prescribed in spite of the risk of recurrence of DAH because of the pregnancy. The patient is currently free from pulmonary problems. Our case shows that the alternative agent, methimazole, can be used to treat hyperthyroidism in a pregnant patient with PTU associated DAH.