This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine, Subject name: Pathology
In malignant hyperthermia the increased heat production is due to : 
Select and explain. 
A. Increased muscle metabolism by excess of calcium ions, B. Thermic effect of food, C. Increased sympathetic discharge, D. Mitochondrial thermogenesis
A: Increased muscle metabolism by excess of calcium ions
Answer: A: Increased muscle metabolism by excess of calcium ions 
Explanation: Ans. is 'a' i.e. increased muscle metabolism by excess of calcium ionsRef Harrison 16th/e p 105 (15th/e page 92)Malignant hyperthermiais caused by inherited abnormality in sarcoplasmic reticulum of skeletal muscleDue to this there is rapid increase in intracellular calcium levels in response to certain drugs.This leads toIncreased muscle metabolismElevated temperatureRhabdomyolysisRigidityAcidosisCardiovascular instabilityIt is often fatalDrugs which cause malignant hyperthermia areHalothane*Succinyl choline*Phenothiazines Haloperidol*