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Related to heat hyperpyrexia: heat exhaustion


profound disturbance of the heat-regulating mechanism of the body, also known as sunstroke. It is characterized by extremely high body temperatures and sometimes by convulsions and coma. The skin is usually hot and dry because the body-cooling process of sweating has ceased. In some cases, however, the skin may feel relatively cool because blood vessels just below the skin have constricted and the overheated blood is not being carried to the surface; an actively exercising person with heatstroke may be sweating freely. Heatstroke is a rare disorder and is more common among elderly and obese people and those with debilitating diseases. Heatstroke, unlike heat exhaustionheat exhaustion,
condition caused by overexposure to sunlight or another heat source and resulting in dehydration and salt depletion, also known as heat prostration. The symptoms are severe headaches, weakness, dizziness, blurred vision, and sometimes unconsciousness.
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, is considered a serious threat to life; treatment must be swift to prevent death or serious brain damage from high body temperature. The body should be cooled as quickly as possible by removing the patient to a cool shady place and applying cold water or ice water to the skin. See first aidfirst aid,
immediate and temporary treatment of a victim of sudden illness or injury while awaiting the arrival of medical aid. Proper early measures may be instrumental in saving life and ensuring a better and more rapid recovery.
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an acute illness of man and animals caused by impaired thermoregulation after prolonged exposure to high environmental temperatures.

In man, heatstroke may develop during work in a hot factory such as a foundry or steel mill, during outdoor work in regions with a hot climate, or during long marches in the heat of the day. Heatstroke may also arise from impaired heat balance in cardiovascular and thyroid diseases, obesity, and dehydration through diarrhea or vomiting. It readily develops in children under one year of age because the thermoregulatory mechanisms are still incomplete.

Heatstroke may be mild, moderate, or severe. The mild form is marked by weakness, headache, nausea, and rapid pulse. Considerable weakness, stupor, fainting, vomiting, and elevation of the body temperature to 39°–40°C are indicative of moderate heatstroke. The severe form sets in abruptly upon prolonged exposure to excessive heat, with loss of consciousness, convulsions, rapid and shallow breathing, slowing of the blood circulation, and elevation of the body temperature to 41°–42°C. This form may be fatal.

First aid consists in removing the victim from the heat, applying cold compresses, and giving him cold water to drink if he is conscious. A victim of severe heatstroke should lie on his side to avoid swallowing vomit. Closed cardiac massage and mouth-to-mouth or mouth-to-nose artificial respiration are used when necessary. Reanimation (resuscitation) in a hospital includes general hypothermia and prevention of such complications as brain or lung edema. Heatstroke may be prevented by regular medical examinations of persons whose work involves exposure to high temperatures and by complying with health regulations regarding clothing, long marches in hot weather, and conditions in hot places of work:


Rukovodslvopo gigiene truda, vol. 1. Moscow, 1965.
Rukovodstvopo tropicheskim bolezniam, 3rd ed. Moscow, 1974.
In animals, heatstroke develops when animals are kept for a long time in hot, crowded, and poorly ventilated places, during transportation or overland drives, or during work in the heat of the day. It is manifested by exhaustion (sometimes preceded by excitation), sweating, labored breathing, rapid pulse, elevated body temperature, unsteady movements, and occasionally convulsions.
Treatment involves keeping the animals in a cool or shady place, applying a cold medium to the head, injecting cardiac stimulants, and bloodletting if symptoms of lung edema are present. Heatstroke may be prevented by observing the rules for maintaining, transporting, and using animals.


A heat-exposure syndrome characterized by hyperpyrexia and prostration due to diminution or cessation of sweating, occurring most commonly in persons with underlying disease.


a condition resulting from prolonged exposure to intense heat, characterized by high fever and in severe cases convulsions and coma