Thyroid storm is a rare, life-threatening disorder of the thyroid characterized by sudden-onset thyrotoxicosis. It is often caused by an acute event such as thyroid surgery, trauma, infection, or iodine load. It may also be caused by oversecretion of thyroid hormone or sudden reduction in thyroid-suppression medication.

Common signs and symptoms include high fever, tachycardia, congestive heart failure, arrhythmia, altered mental status, agitation, tremor, diarrhea, confusion, and sweating.

Management consists of reducing fever, reducing thyroid-hormone release, and identifying and limiting causal factors.