Case report: Death in the emergency department: an unrecognized awake malignant hyperthermia-like reaction in a six-year-old.

A healthy 6-year-old boy developed lower extremity rigidity, trismus, and fever after playing in a splash pool. On arrival in the emergency department, he appeared to be seizing. An endotracheal tube was emergently placed using succinylcholine. Cardiac arrest followed. He could not be resuscitated. Postmortem genetic analysis found a novel RYR1 variant. Family testing revealed the same variant in his father who also had muscle contracture testing diagnostic for susceptibility to malignant hyperthermia and central core disease diagnosed histologically. Because there was no exposure to volatile anesthetics before the onset of symptoms, this is a case of "awake" malignant hyperthermia worsened by succinylcholine.