Myxedema coma is a rare condition that needs emergency care. It 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.

These life-threatening symptoms may occur:

• Mental deterioration such as apathy, confusion, and psychosis
• Extremely low body temperature (hypothermia)
• Extremely slow heartbeat (fewer than 60 beats a minute)
• Heart failure
• Respiratory failure

Death can occur if myxedema coma is not treated. Emergency treatment may include thyroid hormone replacement given in a vein (intravenously) and steroid therapy.