Thyrotoxic storm is a life-threatening condition that develops in cases of untreated thyrotoxicosis ( hyperthyroidism ). This is usually precipitated by an acute stress, such as trauma or infection. Onset is sudden with a pounding heart ( tachycardia ), fever , sweating , restlessness , and shaking (tremulous). Congestive heart failure and pulmonary edema can develop rapidly and lead to death. THIS IS AN EMERGENCY CONDITION. CALL 911 OR OTHER EMERGENCY NUMBER IF YOU HAVE HYPERTHYROIDISM AND EXPERIENCE THESE SYMPTOMS.