A major cause of myxedema coma is which of the following?

• A. Acute infection
• B. Adverse drug reaction
• C. Untreated hypothyroidism
• D. Pituitary failure

Answer: (C)

Myxedema coma happens when a person’s thyroid hormone levels are severely low, so the body's metabolic rate is down and multiple organ systems begin to fail. The situation most often arises in people with longstanding, untreated hypothyroidism; without treatment, the body's reserves to handle stress are exhausted, and a trigger such as infection, cold, or a drug can push them into crisis. The role of the trigger is to precipitate the decompensation, but the fundamental issue is the prolonged lack of thyroid hormone from untreated hypothyroidism. Acute infection or adverse drug reactions can provoke the crisis in someone with thyroid depletion, but they are triggers rather than the primary cause. Pituitary failure can cause low thyroid hormone as well, but the major, most common cause of myxedema coma remains untreated hypothyroidism.