Myxedema coma is a rare condition requiring emergency care that can occur in a person who has untreated, severe hypothyroidism. It usually occurs in older adults who have other illnesses, such as a serious infection or heart attack, along with their hypothyroidism.
The following life-threatening symptoms may occur:
Death can occur if myxedema coma is not treated. Emergency treatment may include thyroid hormone replacement given in a vein (intravenously) and steroid therapy.
WebMD Medical Reference from Healthwise