Diagnosis

Healthcare professionals can often diagnose heatstroke without testing. However, laboratory tests can confirm the diagnosis, rule out other causes for symptoms and find out if there is any organ damage. These tests include:

  • Rectal temperature to check core body temperature. A rectal temperature is the most accurate way of determining core body temperature and is more accurate than mouth or forehead temperatures.
  • A blood test to check blood sodium and potassium and the content of gases in blood to see if there's been damage to the central nervous system.
  • A urine test to check the color of urine because it's usually darker if someone has a heat-related condition. A urine test also checks kidney function, which can be affected by heatstroke.
  • Muscle damage tests to check for serious damage to the muscle tissue, known as rhabdomyolysis.
  • X-rays and other imaging tests to check for damage to the internal organs.

More Information

Lifestyle and home remedies

Home treatment isn't enough for heatstroke. If you have symptoms of heatstroke, seek emergency medical help. Others should take steps to cool you off while waiting for emergency help to arrive. Don't drink any fluids while waiting for medical assistance.

If you notice signs of heat-related illness, lower your body temperature and prevent your condition from progressing to heatstroke. In a lesser heat emergency, such as heat cramps or heat exhaustion, the following steps may lower your body temperature:

  • Get to a shady or air-conditioned place. If you don't have air conditioning at home, go someplace with air conditioning, such as a mall, store or public library.
  • Cool off with damp sheets and a fan. If you're with someone who's experiencing heat-related symptoms, cover the person with damp sheets or spray with cool water. Direct air onto the person with a fan.
  • Take a cool shower or bath. If you're outdoors and not near shelter, soaking in a cool pond or stream can help bring your temperature down.
  • Rehydrate. Drink plenty of fluids. Also, because you lose salt through sweating, you can replenish salt and water with some sports drinks. If your health professional has restricted your fluid or salt intake, check with your health professional to see how much you should drink and whether you should replace salt.
  • Don't drink sugary or alcoholic beverages to rehydrate. These drinks may interfere with your body's ability to control your temperature. Also, very cold drinks can cause stomach cramps.
Sept. 12, 2024
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  3. O'Connor FG, et al. Exertional heat illness in adolescents and adults: Epidemiology, thermoregulation, risk factors, and diagnosis. https://www.uptodate.com/contents/search. Accessed June 25, 2024.
  4. Extreme heat. Ready Campaign. https://www.ready.gov/heat. Accessed June 25, 2024.
  5. O'Connor FG, et al. Exertional heat illness in adolescents and adults: Management and prevention. https://www.uptodate.com/contents/search. Accessed June 25, 2024.
  6. Mechem CC. Severe nonexertional hyperthermia (classic heat stroke) in adults. https://www.uptodate.com/contents/search. Accessed June 25, 2024.
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