Skip to Main Content


  • • Occurs when body core temperature exceeds 40 °C and produces severe CNS dysfunction

    • Result of imbalance between heat production and dissipation

    • Humans dissipate heat via skin by radiation, conduction, convection, and evaporation




  • • Kills approximately 4000 persons each year in the United States

    • Most often affects young people who are exercising in hot environment (military, athletes, laborers, etc.)

    • Sedentary heat stroke is disease of the elderly and can be predicted when ambient temperature > 32.2 °C and relative humidity reaches 50-76%

    • Predisposing factors include:

    • -Dermatitis

      -Use of phenothiazines, β-blockers, diuretics, and anticholinergics

      -Unrelated fever



      -Heavy clothing


Symptoms and Signs


  • • Sudden coma in hot environment

    • Patient temperature > 40 °C is diagnostic

    • Prodrome of dizziness, headache, nausea, chills, and gooseflesh of arms and chest rarely seen

    • Confusion, belligerence, or stupor may precede coma

    • Skin is pink or ashen and sometimes, paradoxically, dry and hot

    • Profuse sweating also common

    • Heart rate ranges from 140 to 170 bpm

    • Hyperventilation may reach 60 breaths a minute with respiratory alkalosis

    • Pulmonary edema and bloody sputum may develop in severe cases

    • Jaundice is common in first few days after onset


Laboratory Findings


  • • No characteristic laboratory abnormalities

    • Hypocalcemia is common

    • Hypophosphatemia may occur

    • Aspartate aminotransferase (AST), lactic dehydrogenase (LDH), and creatine kinase (CK) may be elevated in first few days

    • Acidosis can result from renal failure or lactic acidosis

    • Proteinuria and granular and RBC casts are seen in initial urine specimens

    • Disseminated intravascular coagulation (DIC) pattern not uncommon


  • • Temperature must be taken rectally


  • • Physical exam including rectal temperature

    • Serum electrolytes


  • • Patient should be cooled rapidly

    • -Spraying patient with water that is 15 °C and fanning with warm air is most efficient

      -Immersion in ice water bath also effective

    • Monitor the rectal temperature often

    • Stop cooling when patient's temperature reaches 38.9 °C

    • Shivering controlled with phenothiazines

    • Oxygen should be administered, intubate as needed for Pao2 < 65 mm Hg

    • Fluid, electrolyte management guided by frequent laboratory measurements

    • IV mannitol early if myoglobinuria present

    • DIC may require heparin

    • Acute renal failure may require hemodialysis

    • Inotropes for cardiac insufficiency






  • • Bad prognostic indicators:

    • -Temperature > 42.2 °C

      -Coma > 2 hours



      -AST > 1000 U/L in first 24 hours

    • 10% mortality in those treated promptly

    • Deaths in first few days due to cerebral damage, late deaths from bleeding or organ failure (kidney, liver, heart)




  • • Adherence to graduated schedule of increasing performance that allow acclimatization over 2-3 weeks

    • Unrestricted access to drinking water

    • Clothing and equipment should be lightened



Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessSurgery Full Site: One-Year Subscription

Connect to the full suite of AccessSurgery content and resources including more than 160 instructional videos, 16,000+ high-quality images, interactive board review, 20+ textbooks, and more.

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessSurgery

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.