Severe nonexertional hyperthermia (classic heat stroke) in adults
- C Crawford Mechem, MD, FACEP
C Crawford Mechem, MD, FACEP
- Professor of Emergency Medicine
- Perelman School of Medicine, University of Pennsylvania
Hyperthermia is defined as elevation of core body temperature above the normal diurnal range of 36 to 37.5ºC due to failure of thermoregulation. Hyperthermia is not synonymous with the more common sign of fever, which is induced by cytokine activation during inflammation and regulated at the level of the hypothalamus. A temperature above 40ºC (or 104ºF) is generally considered to be consistent with severe hyperthermia.
The evaluation of severe hyperthermia in adults and the management of nonexertional heat stroke will be reviewed here. Exertional heat illness (including exertional heat stroke), fever in adults, malignant hyperthermia, and neuroleptic malignant syndrome are discussed in detail separately. (See "Exertional heat illness in adolescents and adults: Epidemiology, thermoregulation, risk factors, and diagnosis" and "Exertional heat illness in adolescents and adults: Management and prevention" and "Pathophysiology and treatment of fever in adults" and "Malignant hyperthermia: Clinical diagnosis and management of acute crisis" and "Neuroleptic malignant syndrome".)
Body temperature is maintained within a narrow range by balancing heat load with heat dissipation [1,2]. The body's heat load results from both metabolic processes and absorption of heat from the environment. As core temperature rises, the preoptic nucleus of the anterior hypothalamus stimulates efferent fibers of the autonomic nervous system to produce sweating and cutaneous vasodilation.
Evaporation is the principal mechanism of heat loss in a hot environment, but this becomes ineffective above a relative humidity of 75 percent . The other major methods of heat dissipation—radiation (emission of infrared electromagnetic energy), conduction (direct transfer of heat to an adjacent, cooler object), and convection (direct transfer of heat to convective air currents)—cannot efficiently transfer heat when environmental temperature exceeds skin temperature. The normal regulation of body temperature is discussed separately. (See "Exertional heat illness in adolescents and adults: Epidemiology, thermoregulation, risk factors, and diagnosis", section on 'Thermoregulation in the heat'.)
Temperature elevation is accompanied by an increase in oxygen consumption and metabolic rate, resulting in hyperpnea and tachycardia. Above 42ºC (108ºF), oxidative phosphorylation becomes uncoupled, and a variety of enzymes cease to function. A cytokine-mediated systemic inflammatory response develops, and production of heat-shock proteins is increased. Blood is shunted from the splanchnic circulation to the skin and muscles, resulting in gastrointestinal ischemia and increased permeability of the intestinal mucosa. Hepatocytes, vascular endothelium, and neural tissue are most sensitive to increased core temperatures, but all organs may ultimately be involved. In severe cases, patients develop multi-organ system failure and disseminated intravascular coagulation (DIC) [2,4,5].
- Khosla R, Guntupalli KK. Heat-related illnesses. Crit Care Clin 1999; 15:251.
- Bouchama A, Knochel JP. Heat stroke. N Engl J Med 2002; 346:1978.
- Bross MH, Nash BT Jr, Carlton FB Jr. Heat emergencies. Am Fam Physician 1994; 50:389.
- Bouchama A, Dehbi M, Chaves-Carballo E. Cooling and hemodynamic management in heatstroke: practical recommendations. Crit Care 2007; 11:R54.
- Leon LR, Helwig BG. Heat stroke: role of the systemic inflammatory response. J Appl Physiol (1985) 2010; 109:1980.
- Centers for Disease Control and Prevention (CDC). Heat-related deaths--Chicago, Illinois, 1996-2001, and United States, 1979-1999. MMWR Morb Mortal Wkly Rep 2003; 52:610.
- Klenk J, Becker C, Rapp K. Heat-related mortality in residents of nursing homes. Age Ageing 2010; 39:245.
- Brody GM. Hyperthermia and hypothermia in the elderly. Clin Geriatr Med 1994; 10:213.
- Dann EJ, Berkman N. Chronic idiopathic anhydrosis--a rare cause of heat stroke. Postgrad Med J 1992; 68:750.
- Flynn A, McGreevy C, Mulkerrin EC. Why do older patients die in a heatwave? QJM 2005; 98:227.
- Bendahan D, Kozak-Ribbens G, Confort-Gouny S, et al. A noninvasive investigation of muscle energetics supports similarities between exertional heat stroke and malignant hyperthermia. Anesth Analg 2001; 93:683.
- Hirshey Dirksen SJ, Larach MG, Rosenberg H, et al. Special article: Future directions in malignant hyperthermia research and patient care. Anesth Analg 2011; 113:1108.
- Tek D, Olshaker JS. Heat illness. Emerg Med Clin North Am 1992; 10:299.
- Druyan A, Janovich R, Heled Y. Misdiagnosis of exertional heat stroke and improper medical treatment. Mil Med 2011; 176:1278.
- Seraj MA, Channa AB, al Harthi SS, et al. Are heat stroke patients fluid depleted? Importance of monitoring central venous pressure as a simple guideline for fluid therapy. Resuscitation 1991; 21:33.
- Dematte JE, O'Mara K, Buescher J, et al. Near-fatal heat stroke during the 1995 heat wave in Chicago. Ann Intern Med 1998; 129:173.
- Argaud L, Ferry T, Le QH, et al. Short- and long-term outcomes of heatstroke following the 2003 heat wave in Lyon, France. Arch Intern Med 2007; 167:2177.
- Misset B, De Jonghe B, Bastuji-Garin S, et al. Mortality of patients with heatstroke admitted to intensive care units during the 2003 heat wave in France: a national multiple-center risk-factor study. Crit Care Med 2006; 34:1087.
- Pease S, Bouadma L, Kermarrec N, et al. Early organ dysfunction course, cooling time and outcome in classic heatstroke. Intensive Care Med 2009; 35:1454.
- Bouchama A, Dehbi M, Mohamed G, et al. Prognostic factors in heat wave related deaths: a meta-analysis. Arch Intern Med 2007; 167:2170.
- Naughton MP, Henderson A, Mirabelli MC, et al. Heat-related mortality during a 1999 heat wave in Chicago. Am J Prev Med 2002; 22:221.
- Semenza JC, Rubin CH, Falter KH, et al. Heat-related deaths during the July 1995 heat wave in Chicago. N Engl J Med 1996; 335:84.
- al-Harthi SS, Nouh MS, al-Arfaj H, et al. Non-invasive evaluation of cardiac abnormalities in heat stroke pilgrims. Int J Cardiol 1992; 37:151.
- Akhtar MJ, al-Nozha M, al-Harthi S, Nouh MS. Electrocardiographic abnormalities in patients with heat stroke. Chest 1993; 104:411.
- García-Rubira JC, Aguilar J, Romero D. Acute myocardial infarction in a young man after heat exhaustion. Int J Cardiol 1995; 47:297.
- Garcin JM, Bronstein JA, Cremades S, et al. Acute liver failure is frequent during heat stroke. World J Gastroenterol 2008; 14:158.
- Varghese GM, John G, Thomas K, et al. Predictors of multi-organ dysfunction in heatstroke. Emerg Med J 2005; 22:185.
- Kew M, Bersohn I, Seftel H, Kent G. Liver damage in heatstroke. Am J Med 1970; 49:192.
- al-Mashhadani SA, Gader AG, al Harthi SS, et al. The coagulopathy of heat stroke: alterations in coagulation and fibrinolysis in heat stroke patients during the pilgrimage (Haj) to Makkah. Blood Coagul Fibrinolysis 1994; 5:731.
- Bouchama A, De Vol EB. Acid-base alterations in heatstroke. Intensive Care Med 2001; 27:680.
- Becker BN, Ismail N. The neuroleptic malignant syndrome and acute renal failure. J Am Soc Nephrol 1994; 4:1406.
- Yeo TP. Heat stroke: a comprehensive review. AACN Clin Issues 2004; 15:280.
- Klein Klouwenberg PM, Ong DS, Bonten MJ, Cremer OL. Classification of sepsis, severe sepsis and septic shock: the impact of minor variations in data capture and definition of SIRS criteria. Intensive Care Med 2012; 38:811.
- Lipman GS, Eifling KP, Ellis MA, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness. Wilderness Environ Med 2013; 24:351.
- Hostler D, Northington WE, Callaway CW. High-dose diazepam facilitates core cooling during cold saline infusion in healthy volunteers. Appl Physiol Nutr Metab 2009; 34:582.
- Smith JE. Cooling methods used in the treatment of exertional heat illness. Br J Sports Med 2005; 39:503.
- McDermott BP, Casa DJ, O'Connor FG, et al. Cold-water dousing with ice massage to treat exertional heat stroke: a case series. Aviat Space Environ Med 2009; 80:720.
- Lissoway JB, Lipman GS, Grahn DA, et al. Novel application of chemical cold packs for treatment of exercise-induced hyperthermia: a randomized controlled trial. Wilderness Environ Med 2015; 26:173.
- Zuckerman GB, Singer LP, Rubin DH, Conway EE Jr. Effects of dantrolene on cooling times and cardiovascular parameters in an immature porcine model of heatstroke. Crit Care Med 1997; 25:135.
- Bouchama A, Cafege A, Devol EB, et al. Ineffectiveness of dantrolene sodium in the treatment of heatstroke. Crit Care Med 1991; 19:176.
- Wakino S, Hori S, Mimura T, et al. Heat stroke with multiple organ failure treated with cold hemodialysis and cold continuous hemodiafiltration: a case report. Ther Apher Dial 2005; 9:423.
- Chen WT, Lin CH, Hsieh MH, et al. Stress-induced cardiomyopathy caused by heat stroke. Ann Emerg Med 2012; 60:63.
- Lacunza J, San Román I, Moreno S, et al. Heat stroke, an unusual trigger of Brugada electrocardiogram. Am J Emerg Med 2009; 27:634.e1.
- Erarslan E, Yüksel I, Haznedaroglu S. Acute liver failure due to non-exertional heatstroke after sauna. Ann Hepatol 2012; 11:138.
- DEFINITIONS AND CLINICAL FINDINGS
- RISK FACTORS FOR INCREASED MORTALITY
- DIAGNOSTIC EVALUATION
- DIFFERENTIAL DIAGNOSIS
- Initial treatment and monitoring
- Cooling measures
- Pharmacologic therapy
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS