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  • Updated 07.24.2023
  • Released 02.04.2003
  • Expires For CME 07.24.2026

Heat stroke



Heatstroke is a heat-related illness marked by a sudden rise in core body temperature above 40 °C along with central nervous system dysfunction. There are two primary types: exertional heatstroke, which develops during vigorous physical activity, and classic heatstroke, which happens as a result of passive exposure to extremely hot environmental conditions. Classic heatstroke occurs during extreme environmental heatwaves and contributes to a significant portion of heat-related fatalities. Exertional heatstroke primarily affects young and healthy individuals engaging in strenuous exercise. Mortality rates are 26.5% and 63.2% for exertional and classic heatstroke, respectively. Pathological studies reveal organ damage, inflammation, and thrombosis. Survivors may experience long-term neurologic and cardiovascular complications. Rapid cooling is the primary treatment option. Understanding individual susceptibility, genetic factors, and biomarkers are crucial for precision-based public health interventions. This article describes the pathophysiology, prevention, and management of heat stroke.

Key points

• Neurologic manifestations such as seizures and impairment of consciousness are the most prominent features of heat stroke when core body temperature exceeds 41°C.

• Apart from exposure to excessive heat, several diseases and drugs predispose to heat stroke.

• Rapid cooling by various measures is the most important part of management if temperature goes above 40°C.

Historical note and terminology

Heat stroke, also termed "sun stroke," is characterized by hyperpyrexia with core body temperature greater than 40°C (104°F) and neurologic dysfunction. Heat stroke is the only condition that is a true heat illness as there is clear evidence for a pathological elevation of the core body temperature, and it is recommended that terms such as “heat fatigue”, “heat exhaustion,” and “heat syncope” should be removed from the modern lexicon (34). As an environmental hyperthermia, heat stroke is distinct from fever due to disease. Heat stroke is a total breakdown of thermoregulation, and two classical forms have been described: (1) nonexertional, which occurs during heat waves without physical exertion, and (2) exertional heat stroke, which typically follows strenuous sports.

Heat stroke has been mentioned in the older medical literature under one name or another. Most of the studies of thermoregulation were conducted following introduction into the clinical practice of thermometry in the 19th century. Historical perspectives on thermoregulation have been reviewed elsewhere (08).

A notable victim of this condition was Sir Victor Horsley, the British pioneer of neurologic surgery, who met an untimely death during World War I from heat stroke at the age of 59 years (40).

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