Successful treatment of thyroid storm with plasmapheresis in a patient with methimazole-induced agranulocytosis.

To report a case of a patient with Graves disease presenting with agranulocytosis induced by methimazole, with subsequent thyroid storm and successful therapeutic use of plasmapheresis. The clinical features and laboratory findings in a patient with agranulocytosis and thyroid storm are presented, and the available literature on utilization of plasmapheresis in the setting of thyrotoxicosis is reviewed. A 40-year-old Vietnamese woman with Graves disease was admitted with methimazole-induced agranulocytosis. Treatment with methimazole was discontinued, and therapy with antibiotics, granulocyte colony-stimulating factor, and ibuprofen was initiated. During hospitalization of the patient, her clinical status deteriorated, with development of pericarditis, thrombocytopenia, and thyroid storm. Treatment with plasmapheresis yielded near-euthyroidism in 3 days. Subsequently, she underwent successful total thyroidectomy. Our case highlights the effectiveness of plasmapheresis when clinical situations prohibit the use of traditional treatment methods for thyrotoxicosis or thyroid storm (or both).