Heat exhaustion

Background

1. Definition
   1. Known heat exposure + temp 37-40 + some combination of:
      1. Tachycardia
      2. Sweating (especially when associated with exercise)
      3. N/V
      4. Headache
      5. Fatigue, weakness
      6. Dizziness
      7. Syncope with prompt return of normal mental status
      8. Severe thirst
      9. Normal mental status or mild confusion that responds rapidly (w/in 30min) to cooling
      10. Signs of mild to moderate dehydration
2. Etiology
   1. Occurs via water depletion or sodium depletion (or combination of both)
      1. Water depletion occurs in elderly and persons working in hit environments
      2. Salt depletion occurs when fluid losses replaced w/ hypotonic solutions

Differential Diagnosis

Environmental heat diagnoses

• Heat cramps
• Heat edema
• Heat exhaustion
• Heat tetany
• Heat stroke
• Heat syncope
• Miliaria
• Hyperthermia

Treatment

1. Removal from heat-stressed environment
2. Salt solution
   1. Oral or IV depending on severity
3. Active cooling
   1. Consider dropping temp to 39 if pt does not respond to 30min of fluid replacement

Disposition

• Majority of pts can be discharged
• Consider admision in pts w/ CHF or severe electrolyte disturbances

Complications

1. Heat stroke
2. Heat cramps
3. Rhabdomyolysis (rare)

See Also

• Heat Stroke
• Heat Emergencies

Source

Tintinalli