Heat exhaustion

Background

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