<prompt> In malignant hypehermia, excess heat production is due to:Increased muscle metabolism by excess of calcium ionsThermic effect of foodIncreased sympathetic dischargeMitochondrial thermogenesis  <response>: Malignant hypehermia is an autosomal-dominant disease in which the defect is in RyR1 gene. When such individuals are administered inhalation anaesthetics halothane or ether or muscle relaxant succinylcholine , there is excess release of Ca in the sarcoplasm. This increases muscle metabolism. 