thyroid storm, a crisis of uncontrolled thyrotoxicosis caused by the release into the bloodstream of increased amounts of thyroid hormone. Thyroid storm may occur spontaneously or be precipitated by infection, stress, or a thyroidectomy performed on a patient who is inadequately prepared with antithyroid drugs. Characteristic signs are fever that may reach 106° F, a rapid pulse, acute respiratory distress, apprehension, restlessness, irritability, and prostration. The patient may become delirious, lapse into a coma, and die of heart failure. Also called thyroid crisis.