Heat stroke

Disease Description (Causes and Symptoms)

• Definition and pathophysiology: An emergency condition in which damage to the thermoregulatory center causes an abnormally elevated core body temperature and dysfunction of the central nervous system. In general, the core body temperature (such as rectal temperature) rises to approximately 40°C or higher and is accompanied by altered consciousness.
• Causes: Prolonged exposure to a hot environment (direct sunlight, hot indoor spaces), strenuous exercise (endurance exercise, military training), high-temperature workplaces, inside vehicles, saunas, and other settings. Older adults, children, people with chronic diseases, and those with dehydration or taking medications (diuretics, anticholinergics, antipsychotics, etc.) are at increased risk.
• Main symptoms: High fever, confusion, coma, or abnormal behavior, headache, dizziness, nausea and vomiting, seizures, flushed skin, and skin that is usually hot and dry (non-exertional heat stroke)—however, sweating may continue in exertional heat stroke. Shortness of breath, low blood pressure, and abnormally rapid or slow breathing may also occur.

Treatment Methods

• First aid (at the scene/before transport)
  • Immediately move the person to a cool place and remove their clothing.
  • Evaporative cooling is the most effective: wet the skin with water and use a fan to blow air over it (use of a spray bottle is recommended; a water temperature of approximately 25°C is recommended).
  • Apply cold compresses to areas where major blood vessels pass (the neck, armpits, and groin).
  • If the person is unconscious, secure the airway and support breathing and circulation (provide artificial respiration or cardiopulmonary resuscitation if necessary).
  • Take safety measures during seizures and administer anticonvulsants if necessary.
  • Immediately transport the person to an emergency medical facility.
• Hospital treatment
  • Continuous monitoring of core body temperature (such as rectal temperature).
  • Active reduction of body temperature: depending on the case, whole-body cold-water immersion (especially recommended for exertional heat stroke), forced evaporative cooling, surface cold compresses, and other methods.
  • Airway and breathing support and oxygen administration; fluid therapy for shock and vasopressors if necessary.
  • Prevention and treatment of complications: fluids and alkalinization for muscle injury (rhabdomyolysis), monitoring and treatment of acute kidney injury, liver injury, and coagulation disorders, and correction of electrolyte abnormalities.
  • Tests: blood tests (CK, electrolytes, BUN/Cr, liver enzymes, coagulation tests), urinalysis, electrocardiography, and imaging or neurological tests if necessary.
  • Antipyretics (acetaminophen and NSAIDs) are not effective for lowering the thermoregulatory set point, so they are not the primary treatment.
• Lifestyle management and precautions
  • Because rapid cooling determines the prognosis, first aid is important.
  • After recovery, get sufficient rest and replenish fluids and electrolytes.
  • Neurological abnormalities (such as reduced concentration and memory impairment) may remain after heat stroke, so follow-up observation is necessary.
  • High-risk groups (older adults, people with chronic diseases, and people taking medications) need stricter prevention and caution.

Checklist Before an Outpatient Visit (Including Sample Questions)

• Items to prepare
  • A list of currently used medications (including prescription drugs, over-the-counter medications, herbal medicines, and supplements)
  • Medical history (heart disease, kidney disease, epilepsy, and chronic diseases) and any previous experience with heat stroke
  • The time of onset and course of recent symptoms (when they began and what activity was being performed)
  • Recent measurements such as body temperature, blood pressure, and heart rate (record them if possible)
  • Records of urine color and amount, muscle pain, fatigue, and changes in consciousness
  • Whether first aid was provided at the scene (how quickly cooling was initiated)
  • Recent test results (if available: CK, BUN/Cr, liver enzyme levels, etc.)
• Sample self-check questions before an outpatient visit
  • When did the symptoms begin? Did they occur immediately after a particular activity (exercise or work)?
  • Did you sweat? (This helps distinguish exertional from non-exertional heat stroke.)
  • Was there any change in consciousness, seizure, or disorientation?
  • Did the urine color change (become dark or red)? Is there muscle pain or weakness?

Examples of General Questions to Ask a Doctor

• Does this medication (the medication I am currently taking) increase the risk of heat stroke? Should I stop taking it?
• When and how should I return to daily activities and exercise after recovery?
• Are additional follow-up tests (such as kidney function, muscle enzymes, or neurological tests) needed?
• What lifestyle changes or adjustments to my work environment can help prevent recurrence?

Examples of Disease-Specific Questions

• I am taking a diuretic, anticholinergic, or beta blocker. Is it okay to continue taking the medication? What measures should I take to reduce the risk of heat stroke?
• After being treated for heat stroke, how likely are neurological (cognitive or motor) sequelae to remain, and what tests should be used for follow-up?