Malignant hyperthermia is caused by all except

(A) Thiopentone sodium # MALIGNANT HYPERTHERMIA is the clinical syndrome observed during GA associated with rapidly increasing temperature as great as 1degC/5 minute.> Etiology: It is due to abnormality of Ryanodine receptor which is a calcium releasing channel of sacroplasmic reticulum. Causative agents of malignant hyperthermia> Muscle relaxant: Succinylcholine> Inhalational agents: Halothane (most common); Isoflurane; Enflurane; Desflurane; Methoxyflurane> Local anaesthetics: Lignocaine> Tricyclic antidepressants MAO inhibitors; Phenothiazines> Clinical features of malignant hyperthermia: Hyperthermia (T > 1 09degF); Increased end tidal CO2; Tachycardia, hypertension; Severe metabolic acidosis; Hyperkalaemia, increased creatine phosphokinase; Renal failure; DIC.> Treatment of Malignant Hyperthermia: Stop all anaesthetics; Control temperature; Sodium bicarbonate IV 2-4 meq/kg; Dantrolene 2 mg/kg repeated at every 5 minutes.> There is a fall in intraocular pressure with isoflurane, and isoflurane may precipitate malignant hyperpyrexia.> Halothane classically produces malignant hyperpyrexia in susceptible individuals. There is a reduction in intraocular pressure.