Malignant hyperthermia is a thermoregulatory emergency because it is triggered by certain anesthetics and causes what?

• A. Hypothermia due to reduced metabolism
• B. Uncontrolled skeletal muscle calcium release leading to excessive heat
• C. Excess sweating with vasodilation
• D. Delayed cooling response

Answer: (B)

Uncontrolled release of calcium from skeletal muscle stores in response to triggering anesthetics is what drives malignant hyperthermia. When susceptible individuals are exposed to certain anesthetics (like volatile agents or succinylcholine), calcium floods out of the sarcoplasmic reticulum via the ryanodine receptor. This causes sustained, forceful muscle contractions and a dramatic upsurge in metabolic activity, so the muscles burn ATP at a furious rate. The result is excessive heat production that overwhelms the body's ability to dissipate it, leading to a dangerous rise in body temperature and metabolic disturbances such as acidosis and high carbon dioxide. This is why it’s a thermoregulatory emergency. The other options don’t fit because the problem isn’t excessive cooling or reduced metabolism; it’s an abrupt, massive heat generation from muscle.