Heat injuries can range from minor heat rash to deadly heat stroke.  Knowing how to identify and treat these conditions is essential for all prehospital providers.  In this

• A wide spectrum of illness which includes:
  • Heat Rash (prickly heat)
  • Heat Syncope
  • Heat Cramps
  • Heat Exhaustion
  • Heat Stroke

Heat Exhaustion

Heat exhaustion is a usually not life-threatening condition which results from exposure to heat.  The thermoregulatory mechanisms of the body are still intact, but heat exhaustion may progress to heat stroke if not managed appropriately.

Signs/Symptoms

• Malaise
• Weakness
• Dizziness
• Headache
• Nausea
• Diaphoresis
• Tachycardia
• CBT usually < 40 °C (104 °F)
• Normal Mental Status
• May lead to heat stroke if not  managed properly

Heat Stroke

• Loss of the body’s normal thermoregulatory controls
• Generally categorized into two groups
  • Exertional Heat Stroke
  • Classic Heat Stroke (AKA Non-Exertional Heat Stroke)

Classic Heat Stroke

• Typically affects the extremes of age (Elderly and Infants)
• Often develops over several days
• Risk factors include:
  • Heat waves
  • Lack of air conditioning
  • Poor fluid intake
  • Children left in vehicles

Exertional Heat Stroke

• Primarily affects athletes, military personnel, persons not acclimatized to local conditions
• Onset is acute (usually hours)
• Risk factors include
  • Poor fluid intake
  • Exercise during extreme weather
  • Football players (American Football)

Patient History

• Obtaining a patient history is extremely important in cases of suspected heat stroke.  A patient experiencing heat stroke will probably not be able to give an accurate history on their own, and bystanders may be your best source of information.
  • Specific history to obtain includes:
    • Activity prior to symptoms
    • Hydration status
    • Length of exposure
    • Treatments/First Aid PTA
    • Prescription Medications
      • TCAs
      • Phenothiazines
      • Anticholinergics
      • Salicylates
    • Other drugs
      • Alcohol
      • Cocaine
      • Amphetamines

Read more  Atrial Fibrillation (AFib) and Clot-Provoked Stroke

Signs/Symptoms

• CBT >40°C (104°F)
• Altered Mental Status
• Tachycardia
• Hypotension
• Tachypnea
• Skin may be dry OR diaphoretic
• Coma
• Flaccid limbs (usually)

Managing Heatstroke in the Prehospital Environment

• Assess and manage Airway, Breathing & Circulation
• Remove patient from hot environment
• Assess vital signs to include a rectal temperature
• Remove clothing and begin active cooling
  • Ice water immersion (Preferred)
  • Evaporative Cooling (Mist & Fan)
  • Strategic ice packing
    • Groin
    • Axilla
    • Neck
      • Use caution due to risk of local cold injury
  • Continue to cool until CBT is < 39°C (102°F)
• Continuous cardiac monitoring should be used
• Obtain IV access and administer normal saline while monitoring closely
• Benzodiazepines may be used to manage seizures, agitation or shivering secondary to active cooling.
• DO NOT administer antipyretic medications such as acetaminophen, aspirin, or ibuprofen.  They may worsen the patient’s condition.

Complications

• Hypoglycemia
• Seizures
• Cardiac arrhythmias
• DIC
• ARDS
• MODS

Differential Diagnosis

• Neuroleptic Malignant Syndrome
• Malignant Hyperthermia
  • Dantrolene is Tx for these
• Anticholinergic Toxicity
  • Check pupils for dilation
• Sepsis
  • Evaluate history
• Thyroid Storm
  • Evaluate history
  • Enlarged thyroid is an indicator

Key Points

• Heatstroke is deadly, but survivable if managed aggressively.
• Ice water immersion is the most effective way to cool these patients, but if not available, use other methods such as evaporative cooling.
• Cool the patient first, then transport.
• Obtain a detailed history, and consider all differentials.
• Prevention is the best way to manage heat injuries, educate the public whenever you can.

Thanks for checking out episode 2 of the podcast!  Please let me know what you think of the show by leaving me an honest review in iTunes.  Also, take a moment to subscribe to the site and ensure you don’t miss any new content.  You can also follow me on Facebook and Twitter.  I look forward to connecting with you in the very near future!  Until next time, stay safe, and treat aggressively!

Read more  Endovascular Intervention in Acute Ischemic Stroke: History and Evolution

-Owen

References

Helman RS. Heat Stroke. Background, Pathophysiology, Epidemiology. 2017 May 18 [accessed 2017 May]. http://emedicine.medscape.com/article/166320-overview

Overview of Heat Illness – Injuries; Poisoning. Merck Manuals Professional Edition. [accessed 2017 May]. https://www.merckmanuals.com/professional/injuries-poisoning/heat-illness/overview-of-heat-illness

Stone CK, Humphries RL, editors. Current Diagnosis & Treatment – Emergency Medicine. 6th ed. New York, NY: McGraw Hill; 2008.

Zaremski J. ACSM | ACSM Blog. American College of Sports Medicine. [accessed 2017 May]. http://www.acsm.org/public-information/acsm-blog/2016/08/11/preventing-heat-injury