Heat Exhaustion and Heatstroke

eMedicine Article by Amy Kunihiro, MD

Heat exhaustion—Symptoms often are nonspecific and may be insidious in onset; these symptoms often resemble a viral illness.

• Fatigue and weakness
• Nausea and vomiting
• Headache and myalgias
• Dizziness
• Muscle cramps and myalgias
• Irritability

Causes:

• Illnesses
• Behavior
  • Exercise in a hot environment
  • Lack of air conditioning or proper ventilation
  • Inappropriate clothing (eg, occlusive, heavy, vapor-impermeable)
  • Lack of acclimatization
  • Decreased fluid intake
  • Hot environments (eg, inside of tents or autos in the sun, hot tubs, saunas)
• Drugs/toxins
  • Beta-blockers
  • Anticholinergics
  • Diuretics
  • Ethanol
  • Antihistamines
  • Cyclic antidepressants
  • Sympathomimetics (eg, cocaine, amphetamines)
  • Phenothiazines
  • Lithium
  • Salicylates
• Other risk factors
  • Salt or water depletion
  • Obesity
  • Avoid using acetaminophen, which can worsen existing hepatic damage but cannot reduce body temperature.