Malignant hyperpyrexia: Investigation of a family after a fatal case.

The relatives of a patient who died from malignant hyperpyrexia were examined clinically and biochemically. One fo the deceased's children, an identical twin, undergoing an anesthetic, was found to develop malignant hyperpyrexia on exposure to nitrous oxide. The creatine phosphokinase concentrations in this family were unhelpful as a method of identifying susceptible individuals.