Malignant Hyperthermia Information

This section of the website is designed to educate clinicians about malignant hyperthermia and its diagnosis, treatment and management.

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Malignant hyperthermia (MH) is a rare and potentially fatal disease that is triggered in susceptible individuals by the inhalation gas anesthetics such as isoflurane, desflurane, and sevoflurane as well as succinylcholine, a depolarizing muscle relaxant. MH is a genetic disease with an autosomal dominant pattern of inheritance.

Exposure of MH susceptible individuals to these anesthetic agents triggers a hypermetabolic crisis that reflects deregulation of excitation-contraction (EC) coupling and calcium homeostasis in skeletal muscles. An anesthetic-induced MH episode is manifested as a rapid and uncontrolled rise in myoplasmic Ca2+, leading to sustained skeletal muscle rigidity and hypermetabolism, accompanied by acidosis, hypercapnia, tachycardia and an abnormal rise in body temperature.

Dantrolene is a potent antidote to anesthetic-induced MH. Administration of dantrolene, prompt diagnosis, and treatment have reduced fatality from MH from over 80% to less than 10% in the 1990s. However, recent surveys on the occurrence of MH in North American clinical institutions show alarming statistics: a rise in MH–associated morbidity to 35% and a rise in MH mortality to 14% during the first decade of the 21st century, presumably because of the use of MH-triggering anesthetics outside of conventional hospital settings.

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