Heat exhaustion

Background

Our environment is slowly getting warmer and the core temperature of the world is increasing. The urbanization and the deforestation causes increased exposure to the sun and hot temperatures. Working and living conditions contribute to the exposure and causes increased number of patients to show signs and symptoms of heat exposure. Heat waves are increasing in the urban areas and have shown significant rise in the number of people dying due to heat exposure.

Etiology[1]

  • Occurs via water depletion or sodium depletion or combination
  • Water depletion occurs in elderly and persons working in hot environments
  • Salt depletion occurs when fluid losses are replaced with hypotonic solutions

Clinical Features[2]

Known heat exposure with temperature 37-40C with:

  • Tachycardia
  • Sweating (especially when associated with exercise)
  • Nausea or vomiting
  • Headache
  • Fatigue, weakness
  • Dizziness
  • Orthostatic hypotension with normal mental status
  • Mentation is normal (in contrast to Heatstroke)

Differential Diagnosis

Environmental heat diagnoses

Evaluation

Labs

  • Evidence of hemoconcentration
  • May be hyponatremic, isotonic or hypernatremic
    • Depending on ratio of fluid and electrolyte loss to intake

Treatment[3]

  1. Removal from heat-stressed environment
  2. Volume and electrolyte replacement
    • Oral versus IV depending on severity
  3. Aggressive cooling to 39C if patient does not respond to 30min of fluid replacement

Disposition[4]

  • Majority of patients can be discharged
  • Consider admision in patients with CHF or severe electrolyte disturbances

Complications

See Also

References

  1. Waters T. Heat Emergencies In: Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw Hill Medical. 2011: 1339
  2. Waters T. Heat Emergencies In: Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw Hill Medical. 2011: 1339
  3. Waters T. Heat Emergencies In: Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw Hill Medical. 2011: 1339
  4. Waters T. Heat Emergencies In: Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw Hill Medical. 2011: 1339