Malignant hyperthermia: A runaway thermogenic futile cycle at the sodium channel level

Abstract

Malignant Hyperthermia (“MH”)—the rapid onset of extremely high fever with muscle rigidity—is caused by a runaway heat production futile cycle mediated via the sodium channels at the myoneural receptor sites. MH is not triggered by non-depolarizing muscle relaxants; however, depolarizing muscle relaxants may trigger it [1]. Here we present a de novo hypothesis of how MH is triggered and develops. We believe that the acetylcholine receptor/sodium channels in the muscles of MH susceptible pigs initiate MH by allowing an increased flux of sodium ions when it is depolarized by acetylcholine or other depolarizing agents, such as succinylcholine and Halothane. Our theory is consistent with our observations of the effects of general anesthetics over twenty years. Succinylcholine is a depolarizing agent that is a potent MH trigger.