Thyroid Emergencies: A Narrative Review.

Abstract

Myxedema coma and thyroid storm are rare thyroid emergencies associated with considerable mortality and morbidity. Myxedema coma is a state of decompensated hypothyroidism with widespread multi-organ dysfunction, most notably impaired consciousness, mixed respiratory failure, and hypothermia. Thyroid storm is the extreme state of thyrotoxicosis occurring when a patient's metabolic, thermoregulatory, and cardiovascular compensatory mechanisms are surpassed. Common clinical features of thyroid storm include hyperthermia, neuropsychiatric symptoms, and tachyarrhythmias. Thyroid emergencies usually result from a precipitating event or trigger transforming a previously compensated hypothyroid or thyrotoxic state. The diagnosis of myxedema coma and thyroid storm is established from clinical features in the either already hypothyroid or thyrotoxic patient. In the case of thyroid storm, clinicians may augment their clinical reasoning with the Japanese Thyroid Association Diagnostic Criteria or the Burch-Wartofsky Point Scale. Supportive care for the cardiovascular, respiratory, and thermoregulatory manifestations, as well as possible intercurrent illness or adrenal insufficiency, play a lead role in the management. For myxedema coma, treatment typically includes high dose levothyroxine with the addition of liothyronine for critically ill patients. Management of thyroid storm is multi-pronged and stepwise, consisting of first-line thionamide and beta-adrenergic receptor antagonist therapy as first-line, inorganic iodine, as well as cholestyramine, plasmapheresis, or emergent thyroidectomy in appropriate severely ill patients.