Malignant Hyperthermia: a case report

Malignant hyperthermia manifests clinically as a hypermetabolic crisis when a malignant hyperthermia-susceptible individual is exposed to a volatile anesthetic such as halothane, isoflurane, enflurane, sevoflurane, or desflurane or depolarizing muscular blockers such as succinylcholine. The condition shows autosomal dominant inheritance with reduced penetrance, and is mostly associated with mutations resulting in abnormal ryanodine receptor type 1 or, more rarely, dihydropyridine receptors. Exposure to triggering agents may lead to unregulated passage of calcium from the sarcoplasmic reticulum into the intracellular space, resulting in an acute malignant hyperthermia crisis. Mortality from malignant hyperthermia in the United States was 16,9% in 2001 and 6,5% in 2005, but it is characterized by high morbidity. Therapy is based on suspension of the triggering agent and administration of dantrolene. Diagnosis is possible by biopsy using in vitro contraction tests or DNA screening for malignant hyperthermia. The authors present a case of malignant hyperthermia during myocardial revascularization through off-pump coronary artery bypass graft.