Paeds · acute-care-resuscitation-and-toxicology
Heat illness, hypothermia and environmental emergencies
Also known as Heat stroke · Heat exhaustion · Exertional heat illness · Accidental hypothermia · Environmental hypothermia · Acute mountain sickness · Altitude illness · Lightning injury · Electrical injury
Fellowship guide to heat illness, accidental environmental hypothermia and the principal environmental emergencies in children: the heat-illness spectrum and the cold-water-immersion cooling target, the Swiss hypothermia staging and the rewarming ladder with the hypothermic-arrest defibrillation rules, acute mountain illness with the Lake Louise score and the descent-first rule for high-altitude cerebral and pulmonary oedema, and the lightning reverse-triage and electrical-injury principles.
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Target exams
Red flags
- Collapsed child with a hot environment or exertion and altered mental state — heat stroke until proven otherwise; cool first and transport second
- Core temperature above forty degrees Celsius with confusion, seizure or coma — heat stroke; begin rapid cooling immediately, do not wait for investigations
- Athlete who collapses mid-exercise in heat with a hot, dry or sweaty skin and abnormal behaviour — exertional heat stroke; cold-water immersion to below thirty-nine degrees within thirty minutes
- Child found cold, pale and altered after outdoor exposure — accidental hypothermia; stage by Swiss I to IV, handle gently, use a low-reading thermometer
- Cold child in ventricular fibrillation below thirty degrees — give one shock, then withhold further shocks and adrenaline until the core is above thirty degrees
- Child with headache at altitude and new ataxia or altered consciousness — high-altitude cerebral oedema; immediate descent and dexamethasone
- Child at altitude with dyspnoea at rest, cough and falling saturations — high-altitude pulmonary oedema; descend, give oxygen, add nifedipine
- Child in arrest after a lightning strike — resuscitate first in reverse triage; lightning arrest is survivable with prolonged CPR
Life stages
Care settings
Clinical exam formats
Board mappings
- Recognition and cooling of heat illness from heat exhaustion to heat stroke
- Staging of accidental environmental hypothermia and the first rewarming steps
- Recognition of acute mountain sickness and the descent decision at altitude
- Rapid cooling of exertional heat stroke with cold-water immersion and multi-organ support
- Active internal and extracorporeal rewarming of severe and profound hypothermia
- Management of high-altitude cerebral and pulmonary oedema with descent, dexamethasone and nifedipine
- The heat-illness spectrum and the heat-stroke definition of core over forty degrees with central nervous system dysfunction
- Swiss hypothermia staging and the rewarming ladder
- The Lake Louise score, the altitude descent rule and the acetazolamide, dexamethasone and nifedipine doses
- Short case: the collapsed febrile athlete in a heatwave
- Communication: prevention of paediatric vehicular heatstroke and heat-wave public-health advice
- Acute care: cooling of heat stroke and rewarming of environmental hypothermia
- Public health: heatwave planning, hot-car safety and altitude advice for travelling families
- Safeguarding: unexplained or delayed presentation of environmental injury
- Heat-stroke pathophysiology and the cooling ladder
- Hypothermia staging and rewarming
- Altitude, lightning and electrical injury principles
- Resuscitation scenario: the hyperthermic collapsed child
- Communication: travel and altitude safety advice
- Heat-illness spectrum and rapid cooling of exertional heat stroke
- Environmental hypothermia staging and rewarming
- Acute altitude illness, lightning and electrical injury
- Patient Care: cooling of heat stroke and rewarming of hypothermia
- Medical Knowledge: thermoregulation and the environmental emergencies
- Systems-Based Practice: heatwave and hot-car prevention and retrieval of the cold child
- Medical Expert: management of heat illness, hypothermia and environmental emergencies
- Health Advocate: heatwave and hot-car prevention
- Collaborator: retrieval of the cold child and the high-altitude patient
Overview & Definition
A teenager collapses mid-race on a forty-degree summer afternoon and is carried in hot, confused and sweating; a toddler is found cold and limp on a mountainside after a lost day in the wet; a school group returns from a high-altitude trek and one child has a headache and cannot walk a straight line. These are the three faces of the environmental-thermal emergency, and the decisions in the first minutes decide survival and the brain. Heat illness is the spectrum that runs from heat cramps through heat exhaustion to heat stroke, and heat stroke is defined as a core temperature over forty degrees Celsius accompanied by central nervous system dysfunction — confusion, agitation, ataxia, seizure or coma. The central nervous system feature is the pivot, because a hot child who is alert has heat exhaustion and a hot child who is not has heat stroke. [1] [4]
The two heat-stroke subtypes behave very differently. Exertional heat stroke strikes the young, fit athlete or military recruit during intense exercise in heat, often with sweating still present and a rapid onset, and it carries an excellent prognosis if cooled fast. Classic, non-exertional heat stroke strikes the elderly, the very young and the chronically ill during a heatwave without exercise, often with hot dry skin from anhidrosis, and it carries a high mortality driven by comorbidity and delayed presentation. The same temperature threshold and the same cooling principle apply to both, but the patient and the system differ. [2] [3]
Accidental hypothermia is an unintended fall in core temperature below thirty-five degrees from environmental cold exposure, and it is staged by the Swiss I to IV classification, which pairs the core temperature with the clinical state so that a rescuer can stage a child in the field. This leaf owns non-submersion environmental hypothermia — the child lost in the cold, the neonate in a cold room, the altitude trekker; the drowned hypothermic child is managed with the rescue-breath-first sequence in the sibling submersion leaf, and the rewarming ladder and the hypothermic-arrest rules are shared across both. [5] [6]
Around these two thermal extremes sit the environmental emergencies: acute altitude illness and its life-threatening cerebral and pulmonary forms, lightning injury, and electrical injury. Each has a single dominant treatment — descent for altitude, resuscitation for lightning, source removal and monitoring for electricity — and each rewards the clinician who knows the underlying physiology rather than reaching for a drug. This topic covers all three pillars to the depth a fellowship candidate must defend at viva. [8] [11]
References12ShowHide
- [1]Bouchama A Heat stroke. N Engl J Med, 2002.PMID 12075060
- [2]Leon LR Heat stroke. Compr Physiol, 2015.PMID 25880507
- [3]Casa DJ National Athletic Trainers' Association Position Statement: Exertional Heat Illnesses. J Athl Train, 2015.PMID 26381473
- [4]Gauer RL Heat-Related Illnesses. Am Fam Physician, 2026.PMID 42101601
- [5]Brown DJ Accidental hypothermia. N Engl J Med, 2012.PMID 23150960
- [6]Darocha T Accidental hypothermia. Nat Rev Dis Primers, 2026.PMID 42393082
- [7]Lott C European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances. Resuscitation, 2021.PMID 33773826
- [8]Luks AM Wilderness Medical Society Clinical Practice Guidelines for the Prevention, Diagnosis, and Treatment of Acute Altitude Illness: 2024 Update. Wilderness Environ Med, 2024.PMID 37833187
- [9]Luks AM Medication and dosage considerations in the prophylaxis and treatment of high-altitude illness. Chest, 2008.PMID 18321903
- [10]Roach RC The 2018 Lake Louise Acute Mountain Sickness Score. High Alt Med Biol, 2018.PMID 29583031
- [11]Davis C Wilderness Medical Society practice guidelines for the prevention and treatment of lightning injuries: 2014 update. Wilderness Environ Med, 2014.PMID 25498265
- [12]Koumbourlis AC Electrical injuries. Crit Care Med, 2002.PMID 12528784