Non-exertional heatstroke is a much greater danger: even the healthiest person, if left in a heatstroke-inducing environment without medical attention, will continue to deteriorate to the point of death, and 65% of the most severe cases are fatal even with treatment. Signs and symptoms
Heat stroke generally presents with a hyperthermia of greater than 40.6 °C (105.1 °F) in combination with disorientation. However, high body temperature does not necessarily indicate that heat stroke is present, such as with people in high-performance endurance sports or with people experiencing fevers. Exertional heat stroke is more accurately diagnosed based on a constellation of symptoms rather than just a specific temperature threshold. There is generally a lack of sweating in classic heatstroke, while sweating is generally present in exertional heatstroke.Early symptoms of heat stroke include behavioral changes, confusion, delirium, dizziness, weakness, agitation, combativeness, slurred speech, nausea, and vomiting. In some individuals with exertional heatstroke, seizures and sphincter incontinence have also been reported. Additionally, in exertional heat stroke, the affected person may sweat excessively. If treatment is delayed, patients could develop vital organ damage, unconsciousness and even organ failure. In the absence of prompt and adequate treatment, heatstroke can be fatal. Causes
Heat stroke occurs when thermoregulation is overwhelmed by a combination of excessive metabolic production of heat (exertion), excessive heat in the physical environment, and insufficient or impaired heat loss, resulting in an abnormally high body temperature.
Conductive cooling methods such as ice-water immersion should also be used, if possible. Evaporative and convective cooling by a combination of cool water spray or cold compresses with constant air flow over the body, such as with a fan or air-conditioning unit, is also an effective alternative. The person should not be wrapped in wet towels or clothing as this can act as insulation and increase the body temperature.Aggressive ice-water immersion remains the gold standard for life-threatening heat stroke. This method may require the effort of several people and the person should be monitored carefully during the treatment process. Immersion should be avoided for an unconscious person, but if there is no alternative, the persons head must be held above water. Immersion in very cold water was once thought to be counterproductive by reducing blood flow to the skin and thereby preventing heat from escaping the body core. However, research has shown that this mechanism does not play a dominant role in the decrease in core body temperature brought on by cold water. Dantrolene, a muscle relaxant used to treat other forms of hyperthermia, is not an effective treatment for heat stroke.Hydration is important in cooling the person. In mild cases of concomitant dehydration, this can be achieved by drinking water, or commercial isotonic sports drinks may be used as a substitute. In either exercise- or heat-induced dehydration, electrolyte imbalance can result, and can be worsened by excess consumption of water. Hyponatremia can be corrected by intake of hypertonic fluids.