Rapid recognition and cooling of classic and exertional heat stroke, and ICU management of its multi-organ complications.
At the bedside
Timed steps- 1
Measure core temperature
0 minRectal (or oesophageal/bladder) temperature. Oral, axillary and tympanic readings underestimate.
- 2
Start cooling within 30 minutes
< 30 minBest: cold/ice-water immersion (whole body to neck) for exertional heat stroke, cooling ≥ 0.15 °C/min. If immersion not feasible: strip, spray with water and fan continuously (evaporative), ice packs to neck, axillae and groin, cold wet sheets ('tarp-assisted cooling'). Air conditioning alone is inadequate.
- 3
Cool to target and stop
Aim to reach 39 °C quickly (within 30 min) and stop active cooling at 38.5-39 °C to avoid overshoot hypothermia; monitor temperature continuously.
- 4
ABC and supportive care
Airway protection if GCS ≤ 8 or seizures; oxygen; IV access; cautious isotonic fluids (e.g. 1-2 L, guided by perfusion/POCUS; classic heat stroke in elderly is often not very volume depleted). Benzodiazepines for shivering or seizures.
- 5
Labs and monitoring
Glucose (hypoglycaemia common), electrolytes (Na, K, Ca, PO4), CK, LFT, coagulation (DIC), renal function, ABG/lactate, urine myoglobin, ECG, troponin.
- 6
Treat complications
Rhabdomyolysis: fluids to urine 1-2 mL/kg/h; AKI: RRT as needed; acute liver injury (transaminases peak at 24-72 h); DIC: blood products if bleeding; ARDS; seizures.
- 7
Avoid ineffective or harmful treatments
Antipyretics (paracetamol, NSAIDs) do not work in heat stroke and may harm liver/kidneys. Dantrolene is not recommended.
Shivering or seizures during cooling
Benzodiazepine (diazepam / midazolam)
- Dose
- Midazolam 1-2 mg IV repeated, or diazepam 5-10 mg IV
Cooling methods (approximate rates)
| Method | Cooling rate | Use |
|---|---|---|
| Cold-water / ice-water immersion | ~0.15-0.35 °C/min | Gold standard for exertional heat stroke |
| Evaporative (spray + fan) | ~0.05-0.1 °C/min | When immersion not feasible; classic heat stroke |
| Ice packs to neck, axillae, groin | Low alone | Adjunct |
| Air-conditioned room only | 0.03-0.06 °C/min | Unacceptable as sole method |
Heat stroke
Step 1 of ~5
Rectal temperature; ABC; glucose
Based on National Centre for Disease Control (NPCCHH), MoHFW, Government of India; Epstein Y, Yanovich R. Educational use; follow local protocol.
Pathophysiology
Hyperthermia overwhelms thermoregulation, causing direct cellular injury, gut barrier leak with endotoxaemia, a systemic inflammatory response similar to sepsis, endothelial injury and DIC. Mortality relates to the duration of hyperthermia (degree-minutes), hence 'cool first'.
Evidence
- Cold-water immersion achieves the fastest cooling and near-zero mortality in exertional heat stroke when started immediately [Epstein 2019; WMS 2019].
- The NCDC 2024 guideline sets a target to start cooling within 30 minutes and defines acceptable cooling rates [NCDC 2024].
Controversies
- Immersion in elderly classic heat stroke patients (monitoring, access) versus evaporative methods; any rapid method is better than slow.
- Invasive cooling (cold IV fluids, intravascular devices) as adjuncts.
🇮🇳 India notes
- India's summer heat waves (April-June) cause many heat stroke deaths in outdoor workers, elderly and the homeless. Heat Stroke Management Units are being set up under NPCCHH since 2024.
- Report heat-related illness and deaths on the IHIP surveillance platform as per NCDC guidance.
References
Test yourself
Module quiz · score 70% to complete the module
Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.