Which agent is a known trigger for malignant hyperthermia?

Which agent is a known trigger for malignant hyperthermia?

• A. Etomidate
• B. N2O
• C. Halothane
• D. Ketamine

Answer: (C)

Malignant hyperthermia is a genetic tendency for skeletal muscles to release calcium uncontrollably when exposed to certain anesthesia drugs, leading to a hypermetabolic crisis with high fever, muscle rigidity, acidosis, and potential organ failure. The classic triggers are volatile inhaled anesthetics and the depolarizing muscle relaxant—agents that directly affect calcium handling in the muscle. Among the options, halothane is a volatile inhaled anesthetic and is a well-known trigger for malignant hyperthermia in susceptible individuals. The other agents listed do not trigger malignant hyperthermia in the same way: etomidate and ketamine are nonvolatile, nondepolarizing alternatives used for induction that do not provoke the abnormal calcium release in most MH-susceptible patients, and nitrous oxide is not considered a malignant hyperthermia trigger. Understanding this helps you anticipate risk, avoid triggering agents in susceptible patients, and recognize that if MH occurs, stopping triggers and giving dantrolene with supportive care is essential.

Malignant hyperthermia is a genetic tendency for skeletal muscles to release calcium uncontrollably when exposed to certain anesthesia drugs, leading to a hypermetabolic crisis with high fever, muscle rigidity, acidosis, and potential organ failure. The classic triggers are volatile inhaled anesthetics and the depolarizing muscle relaxant—agents that directly affect calcium handling in the muscle. Among the options, halothane is a volatile inhaled anesthetic and is a well-known trigger for malignant hyperthermia in susceptible individuals. The other agents listed do not trigger malignant hyperthermia in the same way: etomidate and ketamine are nonvolatile, nondepolarizing alternatives used for induction that do not provoke the abnormal calcium release in most MH-susceptible patients, and nitrous oxide is not considered a malignant hyperthermia trigger. Understanding this helps you anticipate risk, avoid triggering agents in susceptible patients, and recognize that if MH occurs, stopping triggers and giving dantrolene with supportive care is essential.