Medicine. Clinical Sign. Abnormally high body temperature, especially that induced for therapeutic purposes. Origin: Gr. Therm = heat This entry appears with permission from the Dictionary of Cell and Molecular Biology. Hyperthermia is elevated body temperature due to failed thermoregulation that occurs when a body produces or absorbs more heat than it dissipates. Extreme temperature elevation then becomes a medical emergency requiring immediate treatment to prevent disability or death. The most common causes include heat stroke and adverse reactions to drugs. The former is an acute temperature elevation caused by exposure to excessive heat, or combination of heat and humidity, that overwhelms the heat-regulating mechanisms. The latter is a relatively rare side effect of many drugs, particularly those that affect the central nervous system. Malignant hyperthermia is a rare complication of some types of general anesthesia. Hyperthermia can also be deliberately induced using drugs or medical devices and may be used in the treatment of some kinds of cancer and other conditions, most commonly in conjunction with radiotherapy. Hyperthermia differs from fever in that the body's temperature set point remains unchanged. The opposite is hypothermia, which occurs when the temperature drops below that required to maintain normal metabolism. An OSH glossary used in safety and health at work which is, adopted by ILO {102}. The term definition has been obtained from the secondary source.