Heat stroke: Difference between revisions
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==Background==
==Background==
*often fatal, if survive probable brain damage
#Universally fatal if left untreated
*usually v young or elderly, poor or socially isolated, no access to air conditioning
#Types
*heat stroke has microvasc thrombosis and endothelial cell damage- like  DIC
##Classic (nonexertional)
###Seen in children and elderly
##Exertional
###Seen in otherwise young, healthy individuals


==Diagnosis==
==Diagnosis==
*Heat Stroke- temp >40 and CNS dz
#Heat exposure + elevated temperature >40C (>104F) + neurologic abnormalities:
*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)
##Inappropriate behavior
##Confusion
##Delirium
##Ataxia
##Coma
##Seizures
#Anhidrosis is frequently present its absence does NOT rule out heat stroke
##Symptoms seen in [[Heat Exhaustion]] may also be present


==Signs & Symptoms==
==DDX==
#heat stroke- hot and altered
#Infectious
#tachy and hyperventilation
##Sepsis
#may have hypotn
##Meningitis
#nonexertional heat stroke- have resp alk
##Encephalitis
#exertional- resp alk and lactic acidosis, also rhabdo and electrolyte abnormalities
##Malaria
#may have muscular rigidity
##Typhoid
#hypoglycemia rare
##Tetanus
#can progress to multiorgan faillure
#Endocrine
##Thyroid storm
##Pheochromocytoma
##DKA
#Neurologic
##Hypothalamic bleeding or infarct
##CVA
##Status epilepticus
#Toxicologic
##Anticholinergic toxidrome
##Sympathomimetic overdose
##Salicylate overdose
##Serotonin syndrome
##Malignant hyperthermia
##Neuroleptic malignant syndrome
##Withdrawal (ETOH, benzo)
 
 
==Work-Up==
#Blood sugar
#CBC
#Chemistry
#VBG
##PaCO2 is often <20 2/2 hyperventiltaion
##Exertional heat stroke often results in lactic acidosis
#Coags
#CK
#UA
#ECG
#CXR
#?CT/LP


==Treatment==
==Treatment==
===General===
===General===
Rapid Cooling
#IVF
#by conduction, evaporaton, convection
##Initiate at a rate that ensures adequate (start w/ NS 250cc/hr)
#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)
===Cooling===
#Goal is to reduce temp to 39C (102.2F) and then stop to avoid overshoot hypothermia
#Antipyretics (ASA and acetaminophen) and dantrolene have no role
#Cooling blankets work too slowly to be employed as sole treatment
#Ice packs to neck, axillae, groin are useful as adjunct only
#Cold IVF is not effective
#Techniques
##Evaporative
###Method of choice
###Spray cool water (15C (59F)) on most of pt's body surface; turn on fan
###Complications
####Shivering (occurs when skin temp is <30C (86F): tx w/ short-acting benzos
####Electrodes not sticking: place on pt's back instead
##Ice-water immersion
###Consider especially in young, healthy pts
###Complications
####Shivering
####Inability to perform defibrillation or resuscitative procedures
##Invasive
###Consider if evaporative cooling / immersion is insufficient
###Cold water gastric lavage, bladder lavage, rectal lavage


===Specific Co-Symptom===
==Complications==
# Shivering: Treat with chlorpromazine, benzodiazepines, or thiopental
#Hypotension
# Seizure: Treated with diazepam or thiopental (dilantin is ineffective)
##BP will usually respond to small fluid bolus (500cc) and body cooling
###If ineffective consider pressors (dopamine or dobutamine)
#Electrolyte abnormalities
##Variable: hypokalemia and hyper or hyponatremia may be seen
#Hematologic
##DIC or abnormal bleeding
#Renal failure
#ARDS
#Seizure
##Tx w/ benzos


==Prognosis==
*cns recovery is a favorable sign- but 20% will have resid damage


==See Also==
==See Also==
Line 42: Line 103:


==Source ==
==Source ==
Mistry, KajiQuestions, Donaldson
Tintinali


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

Revision as of 20:16, 27 August 2011

Background

  1. Universally fatal if left untreated
  2. Types
    1. Classic (nonexertional)
      1. Seen in children and elderly
    2. Exertional
      1. Seen in otherwise young, healthy individuals

Diagnosis

  1. Heat exposure + elevated temperature >40C (>104F) + neurologic abnormalities:
    1. Inappropriate behavior
    2. Confusion
    3. Delirium
    4. Ataxia
    5. Coma
    6. Seizures
  2. Anhidrosis is frequently present its absence does NOT rule out heat stroke
    1. Symptoms seen in Heat Exhaustion may also be present

DDX

  1. Infectious
    1. Sepsis
    2. Meningitis
    3. Encephalitis
    4. Malaria
    5. Typhoid
    6. Tetanus
  2. Endocrine
    1. Thyroid storm
    2. Pheochromocytoma
    3. DKA
  3. Neurologic
    1. Hypothalamic bleeding or infarct
    2. CVA
    3. Status epilepticus
  4. Toxicologic
    1. Anticholinergic toxidrome
    2. Sympathomimetic overdose
    3. Salicylate overdose
    4. Serotonin syndrome
    5. Malignant hyperthermia
    6. Neuroleptic malignant syndrome
    7. Withdrawal (ETOH, benzo)


Work-Up

  1. Blood sugar
  2. CBC
  3. Chemistry
  4. VBG
    1. PaCO2 is often <20 2/2 hyperventiltaion
    2. Exertional heat stroke often results in lactic acidosis
  5. Coags
  6. CK
  7. UA
  8. ECG
  9. CXR
  10. ?CT/LP

Treatment

General

  1. IVF
    1. Initiate at a rate that ensures adequate (start w/ NS 250cc/hr)

Cooling

  1. Goal is to reduce temp to 39C (102.2F) and then stop to avoid overshoot hypothermia
  2. Antipyretics (ASA and acetaminophen) and dantrolene have no role
  3. Cooling blankets work too slowly to be employed as sole treatment
  4. Ice packs to neck, axillae, groin are useful as adjunct only
  5. Cold IVF is not effective
  6. Techniques
    1. Evaporative
      1. Method of choice
      2. Spray cool water (15C (59F)) on most of pt's body surface; turn on fan
      3. Complications
        1. Shivering (occurs when skin temp is <30C (86F): tx w/ short-acting benzos
        2. Electrodes not sticking: place on pt's back instead
    2. Ice-water immersion
      1. Consider especially in young, healthy pts
      2. Complications
        1. Shivering
        2. Inability to perform defibrillation or resuscitative procedures
    3. Invasive
      1. Consider if evaporative cooling / immersion is insufficient
      2. Cold water gastric lavage, bladder lavage, rectal lavage

Complications

  1. Hypotension
    1. BP will usually respond to small fluid bolus (500cc) and body cooling
      1. If ineffective consider pressors (dopamine or dobutamine)
  2. Electrolyte abnormalities
    1. Variable: hypokalemia and hyper or hyponatremia may be seen
  3. Hematologic
    1. DIC or abnormal bleeding
  4. Renal failure
  5. ARDS
  6. Seizure
    1. Tx w/ benzos


See Also

Heat Exhaustion

Source

Tintinali

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