A hypermetabolic response to potent inhalation agents (such as halothane, sevoflurane, desflurane), the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stresses such as vigorous exercise and heat
Almost all patients who are MH susceptible have no phenotypic changes without anesthesia, so it is impossible to diagnose susceptibility without either the exposure to the "trigger" anesthetics or by specific diagnostic testing
Key diagnostic features of MH
Unexplained elevation of expired carbon dioxide
Muscle rigidity
Rhabdomyolysis
Hyperthermia
Acidosis
Hyperkalemia
Diagnosis of MH
Based on clinical presentation or laboratory testing
Principal diagnostic features of MH
Unexplained elevation of end-tidal carbon dioxide (ETCO2) concentration
Muscle rigidity
Tachycardia
Acidosis
Hyperthermia
Hyperkalemia
The variability in the order and time of onset of signs often makes the clinical diagnosis rather difficult
