There is mutation of gene coding for the ryanodine receptors in malignant hyperthermia. Which of the following statements best explains the increased heat production in malignant hyperthemia?
Ans. is 'a' ie increased muscle metabolism by excess of calcium ions (Ref: Harrison, 16/e, p105, p390; Goodman and Gilman's Pharmacology, 10/e, p204)Malignant hyperthermia is a life threatening event triggered by the administration of certain anesthetics and neuromuscular blocking agents.Clinical featuresSevere hyperthymia due to heat production from the skeletal muscles Contracture, rigidity Metabolic acidosis.Tachycardia.Drugs which trigger malignant hyperthermia.Halogenated hydrocarbons anesthetics (halothane, isoflurane and sevoflurane)Succinyl chlorine.MechanismThe event is triggered by uncontrolled release of Ca++ ions from the sarcoplasmic reticulum.Association is seen with mutation in the gene Ry- R1 encoding for the skeletal muscle ryanodine receptors.Treatment.Malignant. hyprthermia should be treated immediately with cessation of anesthesia and intravenous administration of dantrolene. Procainamide should also be administered because of the possibility of ventricular fibrillation.Rapid cooling, inhalation of 100% oxygen and control of acidosis should be considered adjunct therapy.
Increased muscle metabolism by excess of calcium ions
Thermic effect of food
Increased sympathetic discharge
Mitochondrial thermogenesis
General