Moffitt AM Pearls 5/31/17: Hyperthermia and Heat Stroke

Hello everyone!

Thank you Sam Dickman and Matt Schwede for sharing with us a case of a young man who suffered exertional collapse, and was found to be hyperthermic with multi-organ failure, most likely secondary to heat stroke! We had a great report discussing our approach to hyperthermia broadly, and focusing on multiorgan manifestations of heat stroke.

This was our last morning report of the 2017-2018 academic year! Thank you all for the amazing cases you shared with us and for your enthusiasm for medicine. Stay tuned for the first morning report led by your new incoming Moffitt chiefs – Katie Auriemma and Dave Anderson, this upcoming Friday!

With gratitude and love,

SamMy

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TOP PEARLS

  • We generally categorize heat stroke into 2 types: non-exertional vs exertional heat stroke.
  • Especially at extremes of temperatures (hypothermia or hyperthermia), peripheral thermometers have poor correlation with central temperatures (0.5- 2 C in discrepancy)! Always check central T.
  • Remember, heat stroke is a multisystem illness that can cause encephalopathy and various organ damage, including acute liver failure and DIC!


Quick Pearls on Measurement of Fever

  • Thanks Jen, for the following slide. KEY take-home point is that central thermometers (bladder, rectal, esophageal) should be used!
  • Peripheral thermometers have poor correlation with central temperatures; studies have shown a discrepancy of 0.5 – 2 C above or below, with discrepancy worsening at extremes of temperature!

fever.png

Heat Stroke

  • Defined as core body T in excess of 40 C with associated CNS dysfunction in the setting of a large environmental heat load that cannot be dissipated
  • 2 types of heat stroke:

    I. Classic (non-exertional) Heat Stroke – generally affects older patient population (> 70 yo) – affects individuals with underlying comorbidities that impair thermoregulation, prevent heat removal, or interfere with hydration (CV disease, neurologic or psychiatric diseases, beta-blocker use, etc)

    II. Exertional heat stroke – generally affects young, healthy individuals who engage in heavy exercise during periods of high ambient T and humidity – Always run through risk factors for exertional heat stroke (functional, acquired, and congenital) when a young adult presents with this

    • Functional: low physical fitness, reduced skin area to mass ratio (large muscle mass, obesity)
    • Acquired: alcohol prior to activity, meds/supplements, dehydration, infection, sweat gland dysfunction, burn/skin scars, X-ray radiation
    • Congenital: ectodermal dysplasia, chronic idiopathic anhidrosis
  • Hyperthermia causes multi-system organ involvement!
    • Cardiac: ST-segment changes, stress induced cardiomyopathy, sinus tachycardia, conduction abnormalities, Brugada pattern, etc! : usually resolve with rapid re-cooling
    • Hypotension: Due to peripheral vasodilation, cardiac dysfunction, and volume depletion!
    • Seizures
    • Rhabdomyolysis
    • AKI
    • There have been reported cases of acute liver failure secondary to heat-related injury!
    • DIC: usually during first 3 days of illness
  • Management
    • There are no definitive studies supporting any particular approach to cooling in classic heat stroke
    • Evaporative and convective cooling methods are better tolerated for classic heat stroke (spraying patient’s body in lukewarm water while fans are used to blow air over moist skin)
    • Immersion in ice water is rapid and effective in young patients with exertional heat stroke. However, it is associated with increased mortality in elderly patients with classic heat stroke.
    • Pharmacologic therapy (such as dantrolene) is not indicated.

 

 

 

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