Hipertermia maligna

Abstract

Malignant hyperthermia (MH) is a hypermetabolic syndrome of skeletal muscle, characterized by cellular calcium increase and ATP depletion this syndrome is mediated by exposure to general anesthetic agents such as: halothane, enflurane, isoflurane, desflurane, sevoflurane and the neuromuscular blocking agent succinylcholine. Predisposition to MH is marked by a chromosome 19 mutation in the gen coding for sarcoplasmic reticulum ryanodine receptor, mediating excessive calcium release. Incidence of MH is 1:10.000 anesthetic procedures and is characterized by muscle rigidity as an outstanding sign, added to heart arrythmias and tachycardia. Blood pressure becomes unstable together with espiratory pCO2 increase. During acute crisis, bleeding can occur and is linked to thrombocytopenia, factor VIII and fibrinogen decrease. Blood pH decreases because of respiratory and lactic acidosis, plasmatic potassium increases through cell leakeage due to skeletal muscle destruction. Patients may die during acute MH crisis or during follow up days. All general anesthesia settings should have 36 dantrolene stand by vials ready for emergency administration at 2.5 mg/Kg initial dose, repeated after 45 min and then every 30 min up to a final 10 mg/kg dose.