Heat stroke: Difference between revisions
 
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==Background==
==Background==
*Universally fatal if left untreated
*Severe end of heat-related illness spectrum characterized by severe hyperthermia and neurologic dysfunction
*Types
*True emergency - universally fatal if left untreated
**Classic (nonexertional)
**Mortality approaches 30% even with treatment<ref name="Gaudio">Gaudio FG, Grissom CK. Cooling Methods in Heat Stroke. J Emerg Med. 2015 Oct 31.</ref>, and is directly associated with the duration of elevated core temperature
***Seen in children and elderly
*Hallmark is multisystem organ dysfunction from heat-induced damage resulting in systemic inflammatory response
**Exertional
 
***Seen in otherwise young, healthy individuals
===Types===
*Classic (nonexertional) - insidious development over days
**Seen in children and elderly
**During the time of [[heat wave]]
*Exertional - rapid onset during exercise or other exertion
**Seen in otherwise young, healthy individuals


==Clinical Features==
==Clinical Features==
*Heat exposure + elevated temperature >40C (>104F) + neurologic abnormalities:
*Symptoms<ref name="Becker">Becker JA, Stewart LK. Heat-related illness. Am Fam Physician. 2011 Jun 1;83(11):1325-30.</ref>
**Inappropriate behavior
**Elevated temperature >40°C (104°F) '''PLUS'''
**[[Confusion]]
**CNS neurologic abnormalities (e.g. inappropriate behavior, [[Confusion]], [[dysarthria|slurred speech]], [[Delirium]], [[Ataxia]], [[Coma]], [[Seizures]])
**[[Delirium]]
**[[Ataxia]]
**[[Coma]]
**[[Seizures]]
*Anhidrosis is frequently present; however, its absence does NOT rule out heat stroke
*Anhidrosis is frequently present; however, its absence does NOT rule out heat stroke
**Symptoms seen in [[Heat Exhaustion]] may also be present
*May have massive [[rectal bleeding|hematochezia]] secondary to decreased intestinal perfusion and ischemia<ref>Lambert GP. Intestinal barrier dysfunction, endotoxemia, and gastrointestinal  symptoms: the 'canary in the coal mine' during exercise-heat stress? Med Sport Sci. 2008;53:61-73.</ref>


==Differential Diagnosis==
==Differential Diagnosis==
===Environmental===
{{Template:Heat Emergencies}}
{{Template:Heat Emergencies}}


===Non-Environmental===
===Non-Environmental===
*Infectious  
*Infectious  
**[[Sepsis]]
**[[Sepsis (Main)|Sepsis]]
**[[Meningitis]]
**[[Meningitis]]
**[[Encephalitis]]
**[[Encephalitis]]
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**[[Tetanus]]
**[[Tetanus]]
*Endocrine  
*Endocrine  
**[[Thyroid Storm]]
**[[Thyroid storm]]
**[[Pheochromocytoma]]
**[[Pheochromocytoma]]
**[[DKA]]
**[[Diabetic ketoacidosis|DKA]]
*Neurologic  
*Neurologic  
**Hypothalamic bleeding or infarct
**Hypothalamic [[ICH|bleeding]] or [[stroke|infarct]]
**[[CVA]]
**[[Stroke (main)|CVA]]
**[[Status epilepticus]]
**[[Status epilepticus]]
*Toxicologic  
*Toxicologic  
**Anticholinergic toxidrome
**[[Anticholinergic toxicity|Anticholinergic toxidrome]]
**[[Sympathomimetic overdose]]
**[[Sympathomimetic toxicity]]
**[[Salicylate overdose]]
**[[Salicylate toxicity]]
**[[Serotonin syndrome]]
**[[Serotonin syndrome]]
**[[Malignant hyperthermia]]
**[[Malignant hyperthermia]]
**[[Neuroleptic Malignant Syndrome]]
**[[Neuroleptic malignant syndrome]]
**Withdrawal (ETOH, benzo)
**Withdrawal (e.g. [[ETOH withdrawal|ETOH]], [[benzodiazepine withdrawal|benzodiazepines]])


{{AMS and fever DDX}}
{{AMS and fever DDX}}


==Diagnosis==
==Evaluation==
*Diagnosis is made by history and physical exam and exclusion of other diseases
===Workup===
*[[ECG]]<ref>Mimish L. Electrocardiographic findings in heat stroke and exhaustion: A study on Makkah pilgrims. J Saudi Heart Assoc. 2012 Jan; 24(1): 35–39.</ref>
**Most often sinus tachycardia, self-limited
**Less frequently ischemic changes including ST depressions, TWIs
*Core temperature (continuous monitoring is ideal, e.g. with bladder temperature monitor)
*Blood glucose
*Blood glucose
*CBC
*CBC
*Chemistry
*Metabolic panel
*Arterial blood gas or Venous blood gas
*[[LFTs]]
**PaCO2 is often <20 2/2 hyperventilation
*Blood gas
*Lactate
*[[Lactate]]
**Often elevated in exertional heat stroke
*Coagulation studies ([[DIC (Disseminated Intravascular Coagulation)|DIC]])
*Coagulation studies
*Creatine phosphokinase and myoglobin ([[Rhabdomyolysis]])
*Creatine phosphokinase
*[[Urinalysis]]
*Urinanalysis
*[[CXR]]
*[[ECG]]
*[[CT brain]] (± [[LP]]), if indicated (Cerebral Edema)
*Chest x-ray
 
*CT brain and/or[[LP]] as needed
===Evaluation===
*Clinical diagnosis
*Exposure to hot environment and high index of suspicion.


==Treatment==
==Management==
===General===
*Address ABCs
#Remove from environment
*Rapid cooling (see below) - mainstay of treatment
#Address airway, breathing and circulation
**Reduces morbidity/mortality, should be started in prehospital setting if no other life-threats exist<ref name="Becker" />
#IV normal saline
*Remove from environment
#*Bolus if hypotensive
*[[IVF]] (for renal protection and avoiding rhabdomyolysis)
#*Titrate to urine output, start at 250mL/hour
**Bolus if hypotensive
#*Avoid aggressive IV fluid resuscitation unless severely dehydrated
**Infusion titrated to UOP (goal 2-3ml/kg/hr)


===Cooling===
===Rapid Cooling===
*Mainstay of treatment
*Cooling end point should be ~39°C (102.2°F) - no good data for this goal<ref name="Gaudio" />
*Goal is to reduce temp to 39C (102.2F) and then stop to avoid overshoot hypothermia
*No role for: antipyretics or dantrolene
*Antipyretics (ASA and acetaminophen) and dantrolene have no role
*Combination of methods, or adjuncts such as cool IVF may increase efficacy of individual methods
*Cooling blankets work too slowly to be employed as sole treatment
====Techniques====
*Ice packs to neck, axillae, groin are useful as adjunct only
*Cool water immersion - treatment of choice<ref name="Becker" /><ref name="Pryor" />
*Cold IVF is not effective
**Immersion of body to level of torso or neck in cool or ice-water
*Techniques
**Best for exertional heat stroke in young/healthy patients, but benefit shown in elderly patients as well
**Evaporative
**Diffuse application of ice or cold packs to entire body may provide similar benefit (but less data)
***Method of choice
***Applying ice packs only to neck, axillae, groin provides only minimal cooling<ref name="Gaudio" />
***Spray cool water (15C (59F)) on most of pt's body surface; turn on fan
**Benefits: most rapid decrease in temperature, some studies have shown 100% survival (esp when started within 30 minutes of collapse)<ref name="Gaudio" /><ref name="Becker" /><ref name="Pryor">Pryor RR, Roth RN, Suyama J, Hostler D. Exertional heat illness: emerging concepts and advances in prehospital care. Prehosp Disaster Med. 2015 Jun;30(3):297-305.</ref>
***Complications
**Disadvantages: requires special equipment (may not be immediately available), poorly tolerated, unable to provide defibrillation or many other resuscitative measures
****Shivering (occurs when skin temp is <30C (86F): treat with short-acting benzodiazepines
*Evaporative/Convective Cooling
****Electrodes not sticking: place on pt's back instead
**Spray cool water (15°C / 59°F) on patient while directing fans at patient
**Ice-water immersion
**Benefits: Easier to apply in ED and while performing other interventions
***Consider especially in young, healthy pts
**Disadvantages: Slower cooling (than immersion) with slightly higher morbidity/mortality
***Complications
*Invasive Techniques (limited data <ref name="Gaudio" />)
****Shivering
**Bladder Lavage
****Inability to perform defibrillation or resuscitative procedures
**Gastric Lavage
**Invasive
**Thoracic Lavage with chest tubes
***Consider if evaporative cooling or immersion is insufficient
**Cardiopulmonary bypass/ECMO
***Cardiopulmonary bypass
***Cold water gastric, bladder or rectal lavage


==Complications==
==Complications==
*[[Hypotension]]
*[[Hypotension]]
**BP will usually respond to small fluid bolus (500cc) and body cooling
**Usually responds to small fluid bolus (500cc) and body cooling
***If ineffective consider vasopressors (dopamine or dobutamine)
**If no response to fluids → consider [[vasopressors]] (dopamine or dobutamine)
***Avoid peripheral vasoconstriction (norepinephrine)
***Avoid peripheral vasoconstriction (e.g. norepinephrine), which may redirect blood flow away from skin and diminish cooling
****May redirect blood flow away from skin
*[[Electrolyte abnormalities]]
*[[Electrolyte abnormalities]]
**Variable: hypokalemia and hyper or hyponatremia may be seen
**Variable: [[hypokalemia]] and [[hypernatremia|hyper]] or [[hyponatremia]] may be seen
*Hematologic
*Hematologic - [[DIC]] or abnormal bleeding
**[[DIC]] or abnormal bleeding
*[[hepatic failure|Hepatic injury]] - almost always reversible
*Hepatic injury
*[[Renal failure]]
**Almost always reversible
*Renal failure
*[[ARDS]]
*[[ARDS]]
*[[Seizure]]
*[[Seizure]] - treat with [[Benzodiazepines]]
**Treat with [[Benzodiazepines]]
*[[focal neuro deficits|Neurologic deficit]]
*Neurologic deficit
**Persistent in 20%, associated with high mortality
**Persistent in 20%, associated with high mortality


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==References==
==References==
Waters T. Heat Emergencies In: Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw Hill Medical. 2011: 1339
<references/>


[[Category:Environ]]
[[Category:Environmental]]

Latest revision as of 17:01, 5 May 2022

Background

  • Severe end of heat-related illness spectrum characterized by severe hyperthermia and neurologic dysfunction
  • True emergency - universally fatal if left untreated
    • Mortality approaches 30% even with treatment[1], and is directly associated with the duration of elevated core temperature
  • Hallmark is multisystem organ dysfunction from heat-induced damage resulting in systemic inflammatory response

Types

  • Classic (nonexertional) - insidious development over days
    • Seen in children and elderly
    • During the time of heat wave
  • Exertional - rapid onset during exercise or other exertion
    • Seen in otherwise young, healthy individuals

Clinical Features

  • Symptoms[2]
  • Anhidrosis is frequently present; however, its absence does NOT rule out heat stroke
  • May have massive hematochezia secondary to decreased intestinal perfusion and ischemia[3]

Differential Diagnosis

Environmental heat diagnoses

Non-Environmental

Altered mental status and fever

Evaluation

Workup

  • ECG[4]
    • Most often sinus tachycardia, self-limited
    • Less frequently ischemic changes including ST depressions, TWIs
  • Core temperature (continuous monitoring is ideal, e.g. with bladder temperature monitor)
  • Blood glucose
  • CBC
  • Metabolic panel
  • LFTs
  • Blood gas
  • Lactate
  • Coagulation studies (DIC)
  • Creatine phosphokinase and myoglobin (Rhabdomyolysis)
  • Urinalysis
  • CXR
  • CT brain (± LP), if indicated (Cerebral Edema)

Evaluation

  • Clinical diagnosis
  • Exposure to hot environment and high index of suspicion.

Management

  • Address ABCs
  • Rapid cooling (see below) - mainstay of treatment
    • Reduces morbidity/mortality, should be started in prehospital setting if no other life-threats exist[2]
  • Remove from environment
  • IVF (for renal protection and avoiding rhabdomyolysis)
    • Bolus if hypotensive
    • Infusion titrated to UOP (goal 2-3ml/kg/hr)

Rapid Cooling

  • Cooling end point should be ~39°C (102.2°F) - no good data for this goal[1]
  • No role for: antipyretics or dantrolene
  • Combination of methods, or adjuncts such as cool IVF may increase efficacy of individual methods

Techniques

  • Cool water immersion - treatment of choice[2][5]
    • Immersion of body to level of torso or neck in cool or ice-water
    • Best for exertional heat stroke in young/healthy patients, but benefit shown in elderly patients as well
    • Diffuse application of ice or cold packs to entire body may provide similar benefit (but less data)
      • Applying ice packs only to neck, axillae, groin provides only minimal cooling[1]
    • Benefits: most rapid decrease in temperature, some studies have shown 100% survival (esp when started within 30 minutes of collapse)[1][2][5]
    • Disadvantages: requires special equipment (may not be immediately available), poorly tolerated, unable to provide defibrillation or many other resuscitative measures
  • Evaporative/Convective Cooling
    • Spray cool water (15°C / 59°F) on patient while directing fans at patient
    • Benefits: Easier to apply in ED and while performing other interventions
    • Disadvantages: Slower cooling (than immersion) with slightly higher morbidity/mortality
  • Invasive Techniques (limited data [1])
    • Bladder Lavage
    • Gastric Lavage
    • Thoracic Lavage with chest tubes
    • Cardiopulmonary bypass/ECMO

Complications

Disposition

  • All patients require admission

See Also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Gaudio FG, Grissom CK. Cooling Methods in Heat Stroke. J Emerg Med. 2015 Oct 31.
  2. ↑ 2.0 2.1 2.2 2.3 Becker JA, Stewart LK. Heat-related illness. Am Fam Physician. 2011 Jun 1;83(11):1325-30.
  3. ↑ Lambert GP. Intestinal barrier dysfunction, endotoxemia, and gastrointestinal symptoms: the 'canary in the coal mine' during exercise-heat stress? Med Sport Sci. 2008;53:61-73.
  4. ↑ Mimish L. Electrocardiographic findings in heat stroke and exhaustion: A study on Makkah pilgrims. J Saudi Heart Assoc. 2012 Jan; 24(1): 35–39.
  5. ↑ 5.0 5.1 Pryor RR, Roth RN, Suyama J, Hostler D. Exertional heat illness: emerging concepts and advances in prehospital care. Prehosp Disaster Med. 2015 Jun;30(3):297-305.
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