METHIMAZOLE-INDUCED AGRANULOCYTOSIS AND SEPSIS: WAS THYROID STORM PRESENT OR JUST BEING MIMICKED?

Agranulocytosis induced by thioamides is rare, occurring only in 0.2-0.5% of cases. We present the case of a 45-year-old woman previously diagnosed with Graves' disease that discontinued the use of methimazole on her own. She attended the Emergency Department presenting fever (40.5¯C), agitation and diaphoresis. A thyroid storm diagnosis was initially thought, but after laboratory results showing neutrophil count near 0.06x109/L, sepsis due to neutropenia seemed the most logical hypothesis. Cephepime was promptly initiated. For thyrotoxicosis management, cholestyramine and atenolol were prescribed. In her second day of hospitalization, subcutaneous granulocyte colony-stimulating factor was started for an earlier medullar response. The patient was discharged after 7 days with atenolol 50mg/day and instructed to have a definite treatment for Graves disease as soon as possible. Such case purpose is to remember clinicians that sepsis diagnosis can be challenged, especially when a thyroid storm is a possible diagnosis as well. In this particular case, both conditions should be treated, but life-threatening sepsis should have the focus for a quick therapeutic approach.