A patient, Tina was anesthetized with halothane and nitrous oxide and tubocurarine was used for skeletal muscle relaxation. She became hypeensive along with marked muscle rigidity and hypehermia. Lab repos showed that she has developed hyperkalemia and acidosis. This complication was caused by:

(Ref: KDT 6/e p347, 372) The symptoms of the patient (muscle rigidity, hypeension, hypehermia, hyperkalemia and acidosis) suggests the diagnosis of malignant hypehermia. Halothane can precipitate malignant hypehermia is susceptible individuals. SCh increases this incidence. Malignant hypehermia is due to excessive release of Ca2+ from the sarcoplasmic reticulum. Drug of choice for malignant hypehermia is dantrolene that inhibits the release of Ca2+ (by blocking ryanodine receptors in the sarcoplasmic reticulum).