Heat stroke is a life-threatening rise in core temperature, usually above 40 °C (104 °F), with brain dysfunction such as confusion, seizures or coma. It appears as an exertional form in athletes and workers or a classic form in older adults during heat waves, and fast cooling saves lives.
Key symptoms
- Confusion, odd behavior, slurred speech or collapse
- Hot skin, which may be dry or still sweaty
- Headache, dizziness, nausea and vomiting
- Seizures
- Muscle cramps or weakness after exertion in the heat
What you find on exam
- Core temperature, ideally rectal
- Level of consciousness and GCS
- Fast heart rate, fast breathing, low blood pressure
- Hydration status and skin
- Clues to other causes: infection, stimulant drugs, medicines
Tests
- Glucose
- Electrolytes, kidney function and CK for muscle breakdown
- Liver tests and coagulation tests for organ injury
- ECG and urinalysis for myoglobin
Treatment basics
- Cool first, transport second: cold water immersion is the best method
- Without immersion: ice packs to neck, armpits and groin, plus wetting and fanning
- Stop active cooling at about 39 °C (102 °F) to avoid overshoot
- IV fluids for low blood pressure; benzodiazepines for seizures or shivering
- Fever medicines such as acetaminophen do not help in heat stroke
Red flags
- Altered mental status with a high temperature
- Seizures or coma
- Dark urine, bleeding or very low blood pressure
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Related guides
Sources: NASEMSO National Model EMS Clinical Guidelines; NREMT psychomotor skill sheets (EMT and Paramedic); National EMS Education Standards (2021). Written by Making Synapses. Making Synapses is not affiliated with these organizations.