Hyperthermia
Hyperthermia, also known simply as overheating, is a condition in which an individual's body temperature is elevated beyond normal due to failed thermoregulation. The person's body produces or absorbs more heat than it dissipates. When extreme temperature elevation occurs, it becomes a medical emergency requiring immediate treatment to prevent disability or death. Almost half a million deaths are recorded every year from hyperthermia.
| Hyperthermia | |
|---|---|
| Other names | Overheating |
| An analog medical thermometer showing a temperature of 38.7 °C (101.7 °F) | |
| Specialty | Critical care medicine |
| Symptoms | Lack of perspiration, confusion, delirium, decreased blood pressure, increased heart rate and respiration rate, symptoms of dehydration |
| Complications | Organ failure, unconsciousness |
| Causes | Heat stroke |
| Risk factors | Exposure to hot and/or humid environments, physical exertion, wearing personal protective equipment that covers the body, heatwaves |
| Diagnostic method | Based on symptoms or body temperature above 37.7 °C (99.9 °F) |
| Differential diagnosis | Fever |
| Prevention | Maintaining a moderate temperature, regular hydration, taking regular breaks |
| Treatment | Mild: Staying away from hot environments, rehydrating oneself, mechanical cooling, use of a dehumidifier Severe: intravenous hydration, gastric lavage with iced saline, hemodialysis, immersing in ice water |
The most common causes include heat stroke and adverse reactions to drugs. Heat stroke is an acute temperature elevation caused by exposure to excessive heat, or combination of heat and humidity, that overwhelms the heat-regulating mechanisms of the body. 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 caused by a traumatic brain injury.
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. The term is from Greek ὑπέρ, hyper, meaning "above", and θέρμος, thermos, meaning "heat".