Heat Emergencies

Overview

  •  Spectrum
    • Cramps
    • Syncope
    • Exhaustion
    • Stroke
  • Physiology of cooling
    • Radiation: body warmer than environment, heat radiates away
    • Evaporation: environment warmer than body, sweat promotes heat exchange, affected by ambient humidity

Heat cramps

  • Mechanism: fluid/electrolyte depletion resulting in muscle cramps
  • Management: IVF, electrolyte repletion, cooling

Heat syncope

  • Mechanism: vasodilation resulting in hypotension
  • Management: IVF, cooling, rule out alternative etiologies

Heat exhaustion

  • Mechanism: similar to heat cramps
  • Symptoms: influenza-like, headache, fatigue, dizziness, nausea, normal mental status distinguishes from heat stroke
  • Findings: temperature <40°C
  • Management: IVF, cooling

Heat stroke

  • Mechanism: similar to heat cramps
  • Symptoms: prodrome of heat exhaustion
  • Signs: AMS, ataxia, seizure
  • Findings: temperature >40°C
  • Mortality: 30-80%
  • Labs: AST/ALT, coagulopathy, DIC, rhabdomyolysis, ATN/AKI
  • CXR: pulmonary edema
  • Types
    • Classical: elderly, dry skin, mild dehydration, increased mortality
    • Exertional: young athlete, diaphoretic, increased morbidity (organ failure)
  • Management
    • Evaporative cooling
    • Ice packs to large vessels
    • GI lavage
    • Liberal intubation
    • Benzodiazepines or thorazine for inappropriate thermogenesis (shivering)
    • Halt cooling at 40°C