Introduction Large release of thyroid hormone causing systemic effect Associated with Graves' patients undergoing surgery stress (trauma, infection, pregnancy) Presentation Symptoms vomitting hyperpyrexia tachyarrhythmia coma Treatment Medical β-blockers controls tachycardia and other sympathetic symptoms propylthiouracil block de novo thyroid hormone synthesis effective within 1-2 hours post-administration iodine Temporarily inhibits organification and blocks the release of T4 and T3 from the gland known as the Wolff-Chaikoff effect effective within 1-2 hours post-administration hydrocortisone reduces T4 to T3 conversion control underlying autoimmune condition (i.e. Grave's) Non-medical maintain temperature with cooling blanket