The clinical spectrum of hyperthyroidism varies from asymptomatic,subclinical hyperthyroidism to the life-threatening "thyroid storm". Hyperthyroidism is a common form of thyroid disease that mimics many of the common complaints in the emergency department. The diagnosis of hyperthyroidism is often challenging due to the multitude of physical and even psychiatric complaints. Recognition and treatment by emergency physicians of severe hyperthyroidism is critical and can be life saving.