From hyperthyroidism to neutropenia
Thionamide-induced agranulocytosis
Abstract
Introduction: methimazole-induced agranulocytosis is a rare but potentially fatal complication that requires immediate suspension of the drug and prompt treatment measures to control thyroid function.
Case presentation: a 24-year-old man with Graves disease developed febrile neutropenia after 20 days of treatment with methimazole. Plasmapheresis was performed, since continued thionamide treatment was contraindicated, reducing free thyroxine (free T4) and producing clinical improvement. This allowed early total thyroidectomy without complications.
Discussion: although rare, thionamide-induced agranulocytosis is associated with high morbidity and mortality. It is essential to identify warning signs early and suspend the drug. In severe thyrotoxicosis with a contraindication for conventional treatment, plasmapheresis is an effective option for presurgical stabilization.
Conclusion: methimazole-induced agranulocytosis must be recognized early. Plasmapheresis can be a safe therapeutic bridge toward definitive treatment
Copyright (c) 2026 Ericarolina Ospino Lopez, Erik Monroy Sanchez , Oscar Osma Ardila
This work is licensed under a Creative Commons Attribution 4.0 International License.
Acta Medica Colombiana uses the CC-BY 4.0 license. Authors retain all rights over their work.
