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Heat Stroke & Hypothermia

Cool the hot brain; warm the cold dead — temperature is the treatment.

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Your objective: explain the approach, recognize important warning signs, then test your recall.

Abbreviations explained
ACS
Acute coronary syndrome
OMI
Occlusion myocardial infarction
ECG
Electrocardiogram
PE
Pulmonary embolism
POCUS
Point-of-care ultrasound
QTc
QT interval corrected for heart rate
LBBB
Left bundle branch block
RBBB
Right bundle branch block
hs-cTn
High-sensitivity cardiac troponin
CTA
Computed tomography angiography
ICU
Intensive care unit
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The jobCool the hot brain; warm the cold dead — temperature is the treatment.

  1. Measure a true core temperature (rectal/esophageal/bladder) — peripheral temps lie.
  2. Heat stroke: cool first (ice-water immersion when available), then support ABC and look for rhabdo, DIC, and liver injury.
  3. Hypothermia: handle gently, start rewarming and follow the local temperature-specific ALS shock/drug algorithm; discuss ECLS transfer early in arrest or instability.
  4. Submersion: oxygenate and ventilate; C-spine only if the mechanism suggests injury. Call poison centre for bites and stings.

Temperature extremes are treated while you diagnose.

Heat stroke is CNS dysfunction plus typically core temperature ≥40°C — evaporative or (better) ice-water immersion cooling starts immediately; do not wait for a laboratory gold standard. Hypothermia is not dead until warm and dead; afterdrop, arrhythmia, and delayed drugs are the traps. Submersion injury is a hypoxic emergency with optional C-spine when the mechanism fits. Envenomation is regional — antivenom and poison-centre support, not a delay for species certainty.

Classic or exertional heat stroke Critical

Key: Altered mentation + high core temperature — cool immediately to ~39°C. Ice-water immersion is first-line for exertional heat stroke (ACSM/NATA). Antipyretics do not work.

Heat exhaustion vs sepsis vs NMS / serotonin syndrome / sympathomimetic storm Critical

Key: Not every hot altered patient is environmental — toxidrome, rigidity, meds, and infection still apply. Cooling proceeds while you sort.

Accidental hypothermia with cardiac arrest Critical

Key: Prolonged CPR and extracorporeal rewarming when available; use a validated prognostic approach such as HOPE and specialist assessment; no single temperature determines when resuscitation stops. Gentle handling to avoid VF.

Submersion / drowning Critical

Key: Hypoxia is the disease. Rescue breaths, intubation as needed, delayed pulmonary edema. C-spine if diving or trauma mechanism.

Rhabdomyolysis / DIC / acute liver failure after heat stroke Critical

Key: The cooling is not the end — watch CK, coagulation, glucose, and mental status for 24 h.

Severe envenomation (region-specific) Emergent

Key: Snake, scorpion, marine — antivenom when indicated, pressure immobilization per local protocol, poison centre. Do not cut, suck, or tourniquet.

Heat exhaustion / mild hypothermia Common

Key: Normal mentation, milder temperature derangement — oral or passive rewarming/cooling, hydration, and a safe environment.

Tick what your patient has — the banner updates as you go.

Environment, exertion, clothing, drugs (anticholinergics, diuretics, stimulants, neuroleptics, SSRIs)

Last seen well, duration of exposure, submersion details

Heart disease, age, alcohol, homelessness

Bite or sting

species if known, time, first aid already given

Core temperature; GCS and sweating (may be absent in classic heat stroke)

Shivering vs rigid; pupils; frostbite; arrhythmia

Trauma and C-spine indications after submersion

Compartment and bite-site exam; fasciculations (elapid/crotalid patterns)

Bedside

  • Core temperature; ECG (Osborn J waves, VF risk); glucose; SpO₂
  • Strip and cool, or insulate and rewarm, while lines go in

Labs

  • CBC, coagulation, CK, electrolytes, creatinine, LFTs, lactate, ABG/VBG
  • DIC panel and glucose in heat stroke; potassium in hypothermia (rises with rewarming)

Imaging / extras

  • CXR after submersion; CT head if trauma or unexplained coma
  • Do not delay cooling or rewarming for a scanner
Medication safety reminder

Use this as a first-pass prompt; verify all medications, doses, concentrations, contraindications, weight, pregnancy status, and local protocols before administration.

Check indication, allergy, route, renal/hepatic risk, interactions, monitoring, and local formulary.

Discharge

  • Heat exhaustion or mild hypothermia with normal mentation, a safe warm/cool environment, and reliable observation.

Admit

  • Heat stroke after cooling (even if mentation improved), moderate hypothermia, submersion with any respiratory findings, envenomation needing observation.

ICU / ECMO / antivenom pathway

  • Heat stroke with organ failure, hypothermic arrest, severe submersion hypoxia, shock from envenomation.

Use objective reassessment and the local pathway.

Before the next decision · reassess and hand over

Use these learning prompts with the presentation’s pathway. They are not discharge criteria.

  1. Reassess: compare symptoms, observations and examination with the initial assessment and response to treatment.
  2. Warning signs for Heat Stroke & Hypothermia:
    • Any CNS change with a high core temperature
    • Core temperature <30°C or cardiac arrest in the cold
    • Submersion with apnea or foam
    • Rising CK, falling platelets, or hypoglycemia after heat exposure
    • Progressive swelling or paralysis after a bite
    • Anticholinergic or neuroleptic exposure in a heat wave
  3. Reconsider: check unresolved findings and alternative explanations, including the pitfalls below.
  4. Escalate: communicate deterioration, uncertainty or needs beyond the current setting.
  5. Plan the transition: identify outstanding results, responsibility for follow-up, patient understanding and specific return advice.
Review this presentation’s disposition pathway →Practice a handover →

Clinical Pearls

  • Hot and altered: cool now. Cold and lifeless: warm before you stop.
  • Ice-water immersion is the treatment of exertional heat stroke, not a last resort.
  • Antipyretics do not treat environmental hyperthermia.
  • Core temperature, not the forehead thermometer, decides the pathway.

Pitfalls

  • Waiting for a “diagnosis” before cooling a hot, altered patient.
  • Using paracetamol to treat heat stroke.
  • Declaring death in hypothermia before adequate rewarming.
  • Rough handling of the severely hypothermic patient (VF).
  • Skipping C-spine in a diver, or immobilizing every pool drowning.
  • Cutting and sucking snakebites — call the poison centre instead.
PRACTICE REFRESHER

Rapid recall

Test your first action and the dangerous diagnoses before revealing the answer.

01 · First move

Before you scroll, what needs to happen first?

02 · Immediate threats

Name at least two diagnoses that cannot wait.

PRIVATE TO THIS DEVICE

Your learning note

Capture a weak point, a teaching pearl, or a question to take to your next shift.

Review schedule starts when marked reviewed
Altered Mental StatusComa & Depressed LOCFever & SepsisPoisoning & OverdoseECG Guide

Selected guidance · source check 2026-09-07. These 1 source links support selected teaching points, not a complete review of this topic. Check population, setting and local protocol before applying a recommendation.

  • Rosen’s Emergency Medicine, 10th ed. (2023) — heat, cold, submersion, envenomation
  • Wilderness Medical Society & NATA/ACSM exertional heat-stroke statements
  • AHA hypothermia and drowning resuscitation guidance
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