Heat stroke: Difference between revisions
 
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==Background==
==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<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
*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


- often fatal, if survive probable brain damage
==Clinical Features==
*Symptoms<ref name="Becker">Becker JA, Stewart LK. Heat-related illness. Am Fam Physician. 2011 Jun 1;83(11):1325-30.</ref>
**Elevated temperature >40°C (104°F) '''PLUS'''
**CNS neurologic abnormalities (e.g. inappropriate behavior, [[Confusion]], [[dysarthria|slurred speech]], [[Delirium]], [[Ataxia]], [[Coma]], [[Seizures]])
*Anhidrosis is frequently present; however, its absence does NOT rule out heat stroke
*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>


- usually v young or elderly, poor or socially isolated, no access to air conditioning
==Differential Diagnosis==
{{Template:Heat Emergencies}}


- heat stroke has microvasc thrombosis and endothelial cell damage- like  DIC
===Non-Environmental===
*Infectious
**[[Sepsis (Main)|Sepsis]]
**[[Meningitis]]
**[[Encephalitis]]
**[[Malaria]]
**[[Typhoid]]
**[[Tetanus]]
*Endocrine
**[[Thyroid storm]]
**[[Pheochromocytoma]]
**[[Diabetic ketoacidosis|DKA]]
*Neurologic
**Hypothalamic [[ICH|bleeding]] or [[stroke|infarct]]
**[[Stroke (main)|CVA]]
**[[Status epilepticus]]
*Toxicologic
**[[Anticholinergic toxicity|Anticholinergic toxidrome]]
**[[Sympathomimetic toxicity]]
**[[Salicylate toxicity]]
**[[Serotonin syndrome]]
**[[Malignant hyperthermia]]
**[[Neuroleptic malignant syndrome]]
**Withdrawal (e.g. [[ETOH withdrawal|ETOH]], [[benzodiazepine withdrawal|benzodiazepines]])


{{AMS and fever DDX}}


==Diagnosis==
==Evaluation==
===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
*CBC
*Metabolic panel
*[[LFTs]]
*Blood gas
*[[Lactate]]
*Coagulation studies ([[DIC (Disseminated Intravascular Coagulation)|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.


Heat Stroke- temp >40 and CNS dz
==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<ref name="Becker" />
*Remove from environment
*[[IVF]] (for renal protection and avoiding rhabdomyolysis)
**Bolus if hypotensive
**Infusion titrated to UOP (goal 2-3ml/kg/hr)


Heat Exhaustion- thirst, weakness, anxiety, dizzy, HA due to temp and water and salt depletion. Temp can be low, high or normal. (>37 but <40)
===Rapid Cooling===
*Cooling end point should be ~39°C (102.2°F) - no good data for this goal<ref name="Gaudio" />
*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<ref name="Becker" /><ref name="Pryor" />
**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<ref name="Gaudio" />
**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>
**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 <ref name="Gaudio" />)
**Bladder Lavage
**Gastric Lavage
**Thoracic Lavage with chest tubes
**Cardiopulmonary bypass/ECMO


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


==Signs & Symptoms==
==Disposition==
 
*All patients require admission
 
- heat stroke- hot and altered
 
- tachy and hyperventilation
 
- may have hypotn
 
- nonexertional heat stroke- have resp alk
 
- exertional- resp alk and lactic acidosis, also rhabdo and electrolyte abnormalities
 
- may have muscular rigidity
 
- hypoglycemia rare
 
- can progress to multiorgan faillure
 
 
==Treatment==
 
 
General
 
1) Rapid Cooling
 
*by conduction, evaporaton, convection
*continue only until the temperature drops to 38.5 or 39 C to avoid  overshoot hypothermia
*evaporative cooling and iced gastric lavage recommended
**e.g. luke-warm water or wet towels + blowing air with a fan
**ay consider peritoneal and thoracic lavage
*cooling blankets may be effective for mild  heatstroke
*immersing or covering the patient in ice NOT recommended  (causes vasoconstriction and shivering)
 
*no drugs helpful (dantrolene not effective; antipyretics not studied)
 
 
Specific Co-Symptom
 
# Shivering: Treat with chlorpromazine, benzodiazepines, or thiopental
# Seizure: Treated with diazepam or thiopental (dilantin is ineffective)
 
==Prognosis==
 
 
*cns recovery is a favorable sign- but 20% will have resid damage


==See Also==
==See Also==
*[[Heat emergencies]]
*[[Heat exhaustion]]
*[[Acute fever]]


==References==
<references/>


Environ: Heat Exhaustion
[[Category:Environmental]]
 
 
==Source ==
 
 
Mistry, KajiQuestions, Donaldson
 
 
 
 
[[Category:Environ]]

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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