All EMS presentations
EnvironmentalClinical presentation

Heat / cold exposure

A streamlined, differential-led presentation for rapid clinical review.

Clinical snapshot

Twenty-second review

  • Heat illness ranges from dehydration and heat exhaustion to heat stroke with thermoregulatory failure and organ injury; cold exposure slows metabolism and can cause dysrhythmia and coagulopathy.
  • Altered CNS function with hyperthermia, severe hypothermia, shock, dysrhythmia, seizure, or ongoing exposure is time-sensitive.
  • Keep sepsis, endocrine disease, or intoxication in the differential; overlapping or concurrent illness remains possible.
  • For heat / cold exposure, trends and combinations of findings are more informative than one isolated vital sign.
Differentials

Compare the clinical patterns

The repeated material is grouped inside each possibility. Open only the condition you need.

Serious2 conditions
Heat strokeTime-sensitive high-risk possibility

HPI

Clarify type/duration of exposure; environment; core temp if available.

Signs & symptoms

CNS dysfunction, extreme temperature, shock, or dysrhythmia.

Focused exam

Expose appropriately, assess core temperature when available, inspect skin, and look for trauma or multisystem involvement; Reassess after decontamination, warming, cooling, or oxygen support.

Brief pathophysiology

Heat stroke may cause heat / cold exposure through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Stroke is a clinical diagnosis supported by time course and neurologic findings. Blood pressure and glucose affect eligibility and mimics; normal vitals do not exclude stroke.

Blood pressure (mmHg)

Often elevated

Hypertension is common in acute stroke; hypotension suggests another cause or poor perfusion.

Blood glucose (mmol/L)

Check every patient

Hypoglycemia can mimic focal deficit; hyperglycemia may accompany stress or diabetes.

Heart rate (bpm)

Assess rate / rhythm

An irregular rhythm may suggest atrial fibrillation but is not required.

Oxygen saturation (SpO₂)

Usually preserved

Hypoxemia requires correction and may indicate aspiration or another process.

Front-load in the triage report

  • Heat stroke: CNS dysfunction, extreme temperature, shock, or dysrhythmia.
  • Type/duration of exposure.
  • Environment.
Severe hypothermiaTime-sensitive high-risk possibility

HPI

Clarify environment; core temp if available; gcs.

Signs & symptoms

CNS dysfunction, extreme temperature, shock, or dysrhythmia.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Measure temperature reliably when available; assess skin, hydration, neurologic status, rhythm, frostbite or burns, and environmental history.

Brief pathophysiology

Severe hypothermia may cause heat / cold exposure through a time-sensitive process capable of rapid physiological deterioration.

Vital-sign pattern

What the trend may show

Possible pattern

Hypothermia slows cardiac and respiratory activity as severity increases. Handle gently and confirm pulse and breathing for an appropriately prolonged interval when profoundly cold.

Temperature (°C)

Below 35 °C

Core temperature below 35 °C defines hypothermia; measurement method matters.

Heart rate (bpm)

May fall

Bradycardia is expected as cooling becomes moderate or severe.

Respiratory rate (breaths/min)

May fall

Respirations can become slow and difficult to detect.

Blood pressure (mmHg)

May fall

Hypotension may occur with severe hypothermia and impaired cardiac output.

Front-load in the triage report

  • Severe hypothermia: CNS dysfunction, extreme temperature, shock, or dysrhythmia.
  • Environment.
  • Core temp if available.
Common2 conditions
Heat exhaustionCommon presentation pattern

HPI

Clarify type/duration of exposure; environment; core temp if available.

Signs & symptoms

Exposure-related symptoms with preserved mentation may improve after removal and supportive care.

Focused exam

Expose appropriately, assess core temperature when available, inspect skin, and look for trauma or multisystem involvement; Reassess after decontamination, warming, cooling, or oxygen support.

Brief pathophysiology

Heat exhaustion may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.

Vital-sign pattern

What the trend may show

Possible pattern

Heat stroke requires central nervous system dysfunction with severe hyperthermia; skin feel and peripheral measurements may be misleading. Treat rapidly when the clinical picture supports it.

Temperature (°C)

Markedly elevated

Use the most reliable temperature method available; heat stroke is a clinical emergency.

Heart rate (bpm)

Usually elevated

Tachycardia supports increased heat load and circulatory stress.

Blood pressure (mmHg)

May fall

Vasodilation and dehydration can produce hypotension.

Respiratory rate (breaths/min)

Often elevated

Tachypnea is common with heat stress and metabolic demand.

Front-load in the triage report

  • Exposure-related symptoms with preserved mentation may improve after removal and supportive care.
  • Type/duration of exposure.
  • Environment.
Mild hypothermiaCommon presentation pattern

HPI

Clarify environment; core temp if available; gcs.

Signs & symptoms

Exposure-related symptoms with preserved mentation may improve after removal and supportive care.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Measure temperature reliably when available; assess skin, hydration, neurologic status, rhythm, frostbite or burns, and environmental history.

Brief pathophysiology

Mild hypothermia may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.

Vital-sign pattern

What the trend may show

Possible pattern

Hypothermia slows cardiac and respiratory activity as severity increases. Handle gently and confirm pulse and breathing for an appropriately prolonged interval when profoundly cold.

Temperature (°C)

Below 35 °C

Core temperature below 35 °C defines hypothermia; measurement method matters.

Heart rate (bpm)

May fall

Bradycardia is expected as cooling becomes moderate or severe.

Respiratory rate (breaths/min)

May fall

Respirations can become slow and difficult to detect.

Blood pressure (mmHg)

May fall

Hypotension may occur with severe hypothermia and impaired cardiac output.

Front-load in the triage report

  • Exposure-related symptoms with preserved mentation may improve after removal and supportive care.
  • Environment.
  • Core temp if available.
Mimics3 conditions
SepsisImportant alternative presentation

HPI

Clarify type/duration of exposure; environment; core temp if available.

Signs & symptoms

Temperature and behaviour changes may have non-environmental causes.

Focused exam

Expose appropriately, assess core temperature when available, inspect skin, and look for trauma or multisystem involvement; Reassess after decontamination, warming, cooling, or oxygen support.

Brief pathophysiology

Sepsis can resemble heat / cold exposure through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

No single vital sign diagnoses sepsis. New tachypnea, abnormal temperature, tachycardia, or falling pressure—especially with altered mentation or poor perfusion—supports organ dysfunction and urgency.

Respiratory rate (breaths/min)

May rise early

Tachypnea is included in NEWS2 and can precede overt hypotension.

Temperature (°C)

High or low

Absence of fever does not exclude sepsis; hypothermia is concerning.

Heart rate (bpm)

Often rises

Tachycardia is common but may be blunted by age or medication.

Blood pressure (mmHg)

May fall

Relative hypotension and trend matter; profound hypotension can be late.

Front-load in the triage report

  • Temperature and behaviour changes may have non-environmental causes.
  • Type/duration of exposure.
  • Environment.
Endocrine diseaseImportant alternative presentation

HPI

Clarify environment; core temp if available; gcs.

Signs & symptoms

Temperature and behaviour changes may have non-environmental causes.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Measure temperature reliably when available; assess skin, hydration, neurologic status, rhythm, frostbite or burns, and environmental history.

Brief pathophysiology

Endocrine disease can resemble heat / cold exposure through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Hypothermia slows cardiac and respiratory activity as severity increases. Handle gently and confirm pulse and breathing for an appropriately prolonged interval when profoundly cold.

Temperature (°C)

Below 35 °C

Core temperature below 35 °C defines hypothermia; measurement method matters.

Heart rate (bpm)

May fall

Bradycardia is expected as cooling becomes moderate or severe.

Respiratory rate (breaths/min)

May fall

Respirations can become slow and difficult to detect.

Blood pressure (mmHg)

May fall

Hypotension may occur with severe hypothermia and impaired cardiac output.

Front-load in the triage report

  • Temperature and behaviour changes may have non-environmental causes.
  • Environment.
  • Core temp if available.
IntoxicationImportant alternative presentation

HPI

Clarify core temp if available; gcs; shivering or cessation.

Signs & symptoms

Temperature and behaviour changes may have non-environmental causes.

Focused exam

Reassess after decontamination, warming, cooling, or oxygen support; Measure temperature reliably when available; assess skin, hydration, neurologic status, rhythm, frostbite or burns, and environmental history.

Brief pathophysiology

Intoxication can resemble heat / cold exposure through overlapping symptoms or referred physiology despite a different primary mechanism.

Vital-sign pattern

What the trend may show

Possible pattern

Hypothermia slows cardiac and respiratory activity as severity increases. Handle gently and confirm pulse and breathing for an appropriately prolonged interval when profoundly cold.

Temperature (°C)

Below 35 °C

Core temperature below 35 °C defines hypothermia; measurement method matters.

Heart rate (bpm)

May fall

Bradycardia is expected as cooling becomes moderate or severe.

Respiratory rate (breaths/min)

May fall

Respirations can become slow and difficult to detect.

Blood pressure (mmHg)

May fall

Hypotension may occur with severe hypothermia and impaired cardiac output.

Front-load in the triage report

  • Temperature and behaviour changes may have non-environmental causes.
  • Core temp if available.
  • GCS.
Red flags

Findings that should escalate concern

  • Altered CNS function with hyperthermia, severe hypothermia, shock, dysrhythmia, seizure, or ongoing exposure is time-sensitive.
  • Heat stroke or severe hypothermia: CNS dysfunction, extreme temperature, shock, or dysrhythmia.
Related EMS presentations

Continue the clinical pathway

NeurologicAltered LOC / confusionToxicologyPoisoning / toxic exposureTraumaBurnsEnvironmentalSubmersion / drowningEnvironmentalCarbon monoxide exposure
References

Clinical and academic sources

Curated clinical guidance and peer-reviewed evidence supporting this presentation. Current BCEHS guidance, medical direction, and local policy remain authoritative for practice.

BCEHS Handbook — specific CPGs

  1. I01: HypothermiaBC Emergency Health Services Handbook

    Official BCEHS clinical practice guidance for hypothermia.

  2. I02: HyperthermiaBC Emergency Health Services Handbook

    Official BCEHS clinical practice guidance for hyperthermia.

Supporting clinical and academic evidence

  1. CEDIS Presenting Complaint List updateCanadian Association of Emergency Physicians

    Presenting-complaint terminology and categorization context. It does not establish a prehospital “top 100” ranking.

  2. Clinical Practice Guideline SummariesWilderness Medical Society

    Evidence-based guidance for environmental and wilderness emergencies, including heat, cold, altitude, and drowning.

  3. Society of Critical Care Medicine Guidelines for the Treatment of Heat StrokeCritical Care Medicine · 2025

    Rapid recognition, immediate cooling, temperature monitoring, and organ-support priorities in heat stroke.