Heatstroke, First Aid

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Heatstroke, also known as sunstroke, is a form of heat illness. Heat illness occurs when a person's core body temperature rises above a safe level of the body's internal temperature range. Heat cramps are the earliest sign of heat illness. If precautions to cool off and rehydrate at this point are not made, the more severe stage of heat illness, heat exhaustion, can occur in a rapid progression, resulting in a potentially life-threatening situation. The most severe form of heat illness is heatstroke, which may result in shock, brain damage, or death.

See the Heat Cramps or Heat Exhaustion texts via the Disease List for information specific to the earlier stages of heat illness.

First Aid Guide
When heatstroke is suspected, seek emergency medical care immediately. While awaiting emergency medical services, try to cool the person as described below.

Use a combination of the following measures depending on the circumstances and means available:

  • Have the person rest, legs slightly elevated, in a shaded area or cool or air-conditioned building, room, or car.
  • Remove or loosen the person's clothes.
  • Give the person an electrolyte drink, such as Gatorade® or Pedialyte®, or water if not available. Note: You can make a salted drink by adding 1 teaspoon of salt to one quart of water. Do not give beverages that contain caffeine or alcohol.
  • Wrap the person in wet cloth, and position a fan toward him/her. Evaporation of water on the skin aids in cooling.
  • Apply cold compresses (eg, to neck, armpits, groin).

Who's at risk?

People most susceptible to heatstroke are those who are outdoors on a hot, humid day or inside in a poorly ventilated area, particularly children, the elderly, or the obese. Children and the elderly show the fastest progression of symptoms and can collapse suddenly.

Those on certain medications can suffer from heat illness, as well, as medications can alter the way the body handles heat and sun. Those who drink alcohol before, during, or after vigorous activity are more susceptible to heat illness, as are people who do heavy work with inadequate fluid intake.

Even those in excellent health can have heat illness if early symptoms are ignored.

Signs and Symptoms

A person with heatstroke may have:

  • A high body temperature (above 102° F)
  • Skin that is red and hot with lack of sweating (sweating that has stopped)
  • Small pupils
  • A rapid, weak pulse
  • Rapid, shallow breathing
  • Extreme confusion or irritability
  • Weakness
  • Seizures
  • Unconsciousness
You can differentiate the most severe form of heat illness, heatstroke, from less-severe forms by comparing the person's symptoms to those above. Less-severe forms of heat illness can be identified as follows:
  • Heat cramps – Painful muscle cramps (eg, in the legs, arms, abdomen, or back), heavy perspiration, and general weakness/lightheadedness.
  • Heat exhaustion – Feelings of nausea, light-headedness, or thirst, and the person may act irrationally, have dilated pupils (pupils are larger than normal), be very sweaty, or have cool and moist skin that is either reddened or pale.

When to Seek Medical Care

If you suspect heatstroke or there is associated shock, seizures, or unconsciousness, seek emergency medical care.

Treatments Your Physician May Prescribe

The physician will aim to cool the patient down in a controlled fashion, while ensuring he/she stays hydrated and has normal blood flow.

To reduce the patient's temperature as quickly and safely as possible, the physician may use different cooling techniques that involve immersion, evaporation, or invasive means. Medication may be given to control shivering, and urine output will be monitored. The patient's temperature will be monitored for days, as a person who has experienced heatstroke may have an unstable temperature for quite some time.

Trusted Links

MedlinePlus: Heat Illness