hyperpyrexia /hī′pərpīrek″sē·ə/ [Gk, hyper + pyressein, to be feverish] , an extremely elevated temperature that sometimes occurs in acute infectious diseases, especially in young children. Malignant hyperpyrexia, characterized by a rapid rise in temperature, tachycardia, tachypnea, sweating, rigidity, and blotchy cyanosis, occasionally occurs in patients undergoing general anesthesia. A high temperature may be reduced by sponging the body with tepid water, by giving a tepid tub bath, or by administering antipyretic medication, such as aspirin or acetaminophen. See also fever. −hyperpyretic, adj.
