Answer:
Due to an inherited myopathy, there may be abnormality in calcium re-uptake. Increased contraction and oxygen consumption lead to a shift to anaerobic metabolism, lactic acidosis, and heat production. Signs include masseter stiffness, increased end-tidal CO2, erythematous flush, mottled cyanosis, labile blood pressure, and tachypnea. Treatment is: hyperventilate, dantrolene, cooling measures, etc (see PRS 1988; 82: 878). Patients with a family history or history of malignant hyperthermia (MH) themselves can be safely treated using standard MH protocols. Muscle biopsy or preoperative dantrolene is not considered necessary.