Sweating is not seen in

1 heat stroke

2 heat cramps

3 heat fatigue

4 heat syncope



Ans: 1


Classic NEHS is characterized by hyperthermia, anhidrosis, and an altered sensorium, which develop suddenly after a period of prolonged elevations in ambient temperatures (ie, heat waves). Core body temperatures greater than 41°C are diagnostic, although heatstroke may occur with lower core body temperatures.

EHS is characterized by hyperthermia, diaphoresis, and an altered sensorium, which may manifest suddenly during extreme physical exertion in a hot environment.

Two forms of heatstroke exist.
Exertional heatstroke (EHS) generally occurs in young individuals who engage in strenuous physical activity for a prolonged period of time in a hot environment.

Classic nonexertional heatstroke (NEHS) more commonly affects sedentary elderly individuals, persons who are chronically ill, and very young persons.

Classic NEHS occurs during environmental heat waves and is more common in areas that have not experienced a heat wave in many years. Both types of heatstroke are associated with a high morbidity and mortality, especially when therapy is delayed.

When heat gain overwhelms the body's mechanisms of heat loss, the body temperature rises, and a major heat illness ensues. Excessive heat denatures proteins, destabilizes phospholipids and lipoproteins, and liquefies membrane lipids, leading to cardiovascular collapse, multiorgan failure, and, ultimately, death.

Temperatures exceeding 106°F or 41.1°C generally are catastrophic and require immediate aggressive therapy.

Factors that interfere with heat dissipation include an inadequate intravascular volume, cardiovascular dysfunction, and abnormal skin. Additionally, high ambient temperatures, high ambient humidity, and many drugs can interfere with heat dissipation, resulting in a major heat illness. Similarly, hypothalamic dysfunction may alter temperature regulation and may result in an unchecked rise in temperature and heat illness.