Hyperthermia
Quick Hits

An approach to hyperthermia at music festivals

Authors: Drs. Frances Clayton & Ryan Kohler

Editors: Drs. Brendan Munn, Qadeem Salehmohamed & Megan Singh

© Allen McEachern

Background

Music festivals (MFs) are a high-risk environment for developing hyperthermia. From an exogenous standpoint, festivals often take place outside in hot summer weather, with limited access to shade and water. Large, dense crowds also increase ambient heat. Festival-goers may also have increased heat production through exertion (dancing, etc.) and impaired thermoregulation in the context of substance use (eg; MDMA, amphetamines). Other recreational substances may impair judgment and the ability to seek shade and water with prolonged or extreme heat exposure. Hyperthermia at music festivals is usually multifactorial.

Heat illness

These diagnoses exist on a spectrum with overlapping symptoms. See Table 1 for differentiators amongst heat illness diagnoses, as well as spectrum of severity. When in doubt, treat it as the most severe form! Note that heat illnesses may also coincide with important intoxicants, so ruling out Serotonin Syndrome (SS), Neuroleptic Malignant Syndrome (NMS), and sympathomimetic toxicity are key before treating as heat-related illness alone. Finally, when toxicologic contributors are present, it is important to observe patients to exclude deterioration over time.

History

  • Presenting symptoms and onset

    • Nausea/vomiting

    • Confusion, agitation, seizure etc.

  • Exposure history: 

    • Physical location(s) and duration(s)

    • Recreational substances (timing, dosage)

  • Medical history and medications

    • SSRIs, antipsychotics, ASA, anticholinergics, etc.

Physical Exam

  • Vitals: Temperature, HR, RR, BP, glucose

  • GCS 

  • Exam features for toxicologic-associated etiology

    • Clonus (check at ankle and for ocular clonus; note ketamine may confound) → indicative of 

    • SS. Brief (a few beats) of inducible clonus is common with SSRIs/serotonergic agents. Sustained or spontaneous clonus is concerning for SS. 

    • Rigidity (lift under knee, positive if ankle comes off bed) → indicative of SS or NMS

    • Dry axillae → Anticholinergic toxicity

Investigations

  • Finger stick glucose

  • iSTAT: CBC, lytes esp Na+, urea, creat, VBG

  • ECG: look for clues to a toxidrome (eg; long QT, wide QRS, dominant R wave in AVR)

  • Urine dip: look for blood/ketones, eg Rhabdo

Differential Diagnosis

Less likely culprits

  • CNS disease

    • Hypothalamic dysfunction (eg. CVA)

  • Endocrinopathy

    • Thyroid storm

    • Pheochromocytoma

  • Infection or sepsis

  • Toxicologic

    • ASA

More likely culprits

  • Exposure: Heat illness

  • Toxicologic

    • Serotonergic agents (esp MDMA) - SS

    • Sedative withdrawal (EtOH, benzos, GHB)

    • Sympathomimetics

    • Antipsychotics - NSM

    • Anticholinergic toxicity

Management

The priorities for hyperthermia at MFs are rapid cooling and benzodiazepine administration, followed by consideration of transport to hospital. This is especially for toxicological causes. See below for a summary of treatment and management priorities.

DO:

  • Rapidly cool those of 40C to < 38C

    Ice bath immersion is the quickest way to do this. The protocols used in endurance running literature suggest immediate immersion for 5 minutes, with a single repeat (for 10 mins total) if T<38C not achieved the first time. If possible, obtain intravenous access to manage sedation as well as the possibility of cardiac instability.

    Secure intravenous access and monitors while in water, and minimize electrical hazards to patients and providers where possible.

    Intubation is rarely needed, but if intubating, use rocuronium to paralyze as succinylcholine is theorized to worsen any potential hyperkalemia. 

    Other cooling options: cooled IV fluids plus evaporative cooling using misting, water, and fans. Ice packs to critical areas are secondary options if multiple patients and only one ice bath.

  • Sedate with Benzodiazepines

  • Transport to the closest hospital for ongoing management if unstable, persistent hyperthermia, other mitigating factors, or provider concern.

DON’T:

  • Don’t use antipyretics, as Acetaminophen and NSAIDs have no role in heat management/mitigation.

  • Don’t use antipsychotics for sedation as they can impair thermoregulation (and would worsen NMS).

RESOURCES // REFERENCES

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