RESUMO
Diffuse alveolar hemorrhage (DAH) is a life-threatening condition associated with many disorders. Here, we report a case of 59-year-old female who had diffuse alveolar hemorrhage associated with methimazole. She had been treated with methimazole for two weeks due to the recurrence of Grave's disease, before visiting the emergency room. She had to be intubated on the 3rd day of hospitalization because of unabated massive hemoptysis and rapid progression of diffuse alveolar infiltration on chest radiographs. Since her clinical condition improved substantially after cessation of methimazole and steroid pulse therapy, she was extubated on the 9th day of hospitalization and then discharged. After discharge, DAH did not recur with cessation of steroid and she had radioactive iodine therapy for her Grave's disease. This was a rare and interesting case of life-threatening DAH associated with cytoplasmic-antineutrophil cytoplasmic antibody and methimazole.