Heat exhaustionMANAGEMENT

TRAUMA PRESENTATIONS · 12 SECTIONS

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548 items

☷ Legend

01Approach to the Critical Patient/attcp48

Triage and immediate risks

›Heat illness triage

›Core temperature usually <40 C

›If core temperature >=40 C, treat as heat stroke

›Mental status intact or mild fatigue only

›If altered mental status, treat as heat stroke until proven otherwise

›Vital sign pattern

›Tachycardia

›Orthostatic hypotension

›High-risk features

›Syncope

›Persistent vomiting

›Chest pain

›Dyspnea

›Oliguria

›Escalation triggers

›If altered mental status, immediate resuscitation bay escalation

›Airway protection if inability to protect airway

›Rapid active cooling strategy

›If SBP <90 mmHg after fluids, shock workup and critical care consult

›Alternate diagnosis evaluation

›Vasopressor support per shock protocol if refractory

›If suspected exertional heat stroke, activate rapid cooling logistics

›Ice water immersion if available and feasible

›Continuous rectal temperature monitoring

Core temperature and monitoring

›Temperature assessment

›Rectal temperature for accuracy when moderate to severe illness

›Oral and tympanic underestimation risk

›Repeat temperature trend

›Every 15-30 minutes during active cooling

›Monitoring bundle

›Cardiac monitor for tachyarrhythmia risk

›Electrolyte abnormality correlation

›Blood pressure trend including orthostatics

›Supine to standing change

›Urine output targets

›>=0.5 mL/kg/hour

Initial stabilization priorities

›Stabilization priorities

›Airway and breathing assessment for alternate diagnoses

›Hypoxia suggests pneumonia, PE, asthma, aspiration

›Circulation and perfusion

›Capillary refill and skin perfusion

›Rapid cooling initiation

›Remove from heat source

›Remove excess clothing and equipment

›Shade and airflow

›Fluids and electrolytes

›Oral rehydration if able

›IV isotonic fluids if unable to tolerate oral

02History/hx72

Exposure and context

›Heat exposure profile

›Ambient temperature and humidity

›Heat index context

›Duration of exposure

›Onset timing of symptoms

›Exertional vs passive exposure

›Athletic training or labor

›Non-exertional environmental exposure

›Protective equipment and clothing

›Impermeable gear

›Helmet and padding use

›Hydration and salt balance

›Fluid intake volume and type

›Water only intake pattern

›Electrolyte solution intake pattern

›Sweating history

›Profuse diaphoresis

›Reduced sweating

›Urine output and color

›Oliguria

›Dark urine

›Symptom pattern

›Weakness and fatigue

›Activity limitation

›Dizziness or presyncope

›Orthostatic symptoms

›Headache

›Thunderclap exclusion cues

›Nausea and vomiting

›Oral intolerance

›Muscle cramps

›Heat cramps association

›Syncope event details

›Exertional collapse timing

›Neurologic red flags

›Confusion

›Heat stroke concern

›Seizure

›Heat stroke concern

›Ataxia

›Heat stroke concern

›Risk factors and comorbidities

›Prior heat illness

›Recurrence risk

›Deconditioning or recent illness

›Viral gastroenteritis

›Cardiovascular disease

›Reduced heat tolerance

›Diabetes

›Dehydration vulnerability

›Chronic kidney disease

›Volume and electrolyte vulnerability

›Medications and substances

›Diuretics

›Volume depletion risk

›Anticholinergics

›Impaired sweating risk

›Antipsychotics

›Thermoregulation impairment risk

›SSRIs and SNRIs

›Hyponatremia risk

›Stimulants

›Heat production increase

›Alcohol

›Dehydration risk

›Occupational and athletic context

›Acclimatization status

›First week of heat exposure risk

›Rest breaks and cooling access

›Cooling station availability

›Team cluster cases

›Shared exposure event

03Physical Exam/exam63

General and vital signs

›Clinical severity snapshot

›Appearance

›Exhaustion

›Distress

›Temperature trend

›Afebrile after cooling suggests response

›Heart rate

›Tachycardia suggests dehydration

›Blood pressure

›Orthostatic hypotension

›Respiratory rate

›Hyperventilation suggests anxiety, metabolic acidosis, pulmonary disease

›Hydration status

›Mucous membranes

›Dryness

›Skin turgor

›Decreased turgor

›Capillary refill

›Delayed refill

›Jugular venous pressure estimate

›Low volume state clues

Skin and thermoregulation findings

›Skin findings

›Diaphoresis common in heat exhaustion

›Profuse sweating

›Hot skin

›Warm to touch

›Rash patterns

›Miliaria rubra

›Peripheral edema and heat

›Heat edema

›Dependent swelling in non-acclimatized

Neurologic and mental status

›Mental status

›Orientation

›Normal orientation supports heat exhaustion

›Attention and concentration

›Mild impairment suggests progression risk

›Gait and coordination

›Ataxia suggests heat stroke or alternate neuro cause

›Focal neurologic deficit screen

›Cranial nerve deficit

›Stroke mimic concern

›Unilateral weakness

›Stroke concern

Cardiopulmonary and abdominal

›Cardiac exam

›Rhythm regularity

›Arrhythmia clues

›Murmur and perfusion

›Structural disease clues

›Lung exam

›Wheeze or crackles

›Alternate diagnosis clues

›Work of breathing

›Heat stress vs pulmonary pathology

›Abdominal exam

›Tenderness pattern

›Alternate diagnosis clues

›Bowel sounds

›Gastroenteritis consideration

›Musculoskeletal

›Muscle tenderness

›Rhabdomyolysis concern

›Cramp distribution

›Heat cramps overlap

04Differential Diagnosis/ddx62

Heat illness spectrum

›Heat exhaustion

›ICD-10 T67.5

›SNOMED CT heat exhaustion concept mapping

›Heat stroke

›ICD-10 T67.0

›Core temperature >=40 C

›CNS dysfunction

›Heat syncope

›ICD-10 T67.1

›Orthostatic collapse after heat exposure

›Heat cramps

›ICD-10 T67.2

›Painful muscle spasms after sweating

Mimics and competing diagnoses

›Dehydration and volume depletion

›ICD-10 E86.0

›Orthostasis without heat as primary driver

›Hyponatremia including exercise-associated hyponatremia

›ICD-10 E87.1

›Headache

›Nausea

›Confusion or seizure

›Hypoglycemia

›ICD-10 E16.2

›Diaphoresis

›Tremor

›Confusion

›Sepsis

›ICD-10 A41.9

›Fever with infectious source

›Hypotension refractory to fluids

›Acute coronary syndrome

›ICD-10 I21.9

›Chest pain or equivalent

›Risk factors and ECG changes

›Pulmonary embolism

›ICD-10 I26.99

›Dyspnea

›Pleuritic pain

›Hypoxia

›Thyroid storm

›ICD-10 E05.91

›Hyperthermia

›Agitation

›Diarrhea

›Drug induced hyperthermia syndromes

›Serotonin syndrome

›ICD-10 T43.225A

›Clonus and hyperreflexia

›Neuroleptic malignant syndrome

›ICD-10 T43.3X5A

›Rigidity

›Anticholinergic toxicity

›ICD-10 T44.3X1A

›Dry skin

›Mydriasis

›CNS event

›Stroke

›ICD-10 I63.9

›Focal deficit

›Intracranial hemorrhage

›ICD-10 I61.9

›Sudden severe headache

05Laboratory Tests/lt44

Core labs and dehydration profile

›Initial lab set based on severity

›Basic metabolic panel

›Sodium and chloride for salt balance

›Hyponatremia threshold <135 mmol/L

›Severe threshold <120 mmol/L

›Potassium for cramping and renal risk

›Hyperkalemia concern with rhabdomyolysis

›Bicarbonate for acid base status

›Low bicarbonate suggests lactic acidosis

›Creatinine and urea for AKI

›Prerenal azotemia pattern

›Glucose point-of-care

›Hypoglycemia exclusion

›Complete blood count when infection or anemia concern

›Leukocytosis nonspecific with stress

›Hemoconcentration with dehydration

›Serum osmolality when hyponatremia suspected

›Hypotonic hyponatremia confirmation

›Serum osmolality <275 mOsm/kg

›Urinalysis when AKI or rhabdomyolysis concern

›Specific gravity for dehydration

›High specific gravity suggests volume depletion

›Blood positive with few RBCs

›Myoglobinuria suggestion

Rhabdomyolysis and organ injury screening

›Rhabdomyolysis screen when exertional illness or muscle pain

›Creatine kinase

›Rising trend supports exertional rhabdomyolysis

›Severe risk often with CK >5000 U/L

›AST and ALT

›Muscle contribution possible

›Phosphate and calcium

›Hyperphosphatemia with cell breakdown

›Early hypocalcemia possible

›Coagulation profile if severe systemic illness concern

›INR and aPTT

›DIC concern in heat stroke

›Lactate when shock physiology or severe symptoms

›Elevated lactate suggests hypoperfusion

›Not specific for heat illness

Pregnancy and toxin specific labs when indicated

›Pregnancy test when applicable

›Urine or serum hCG

›Drug screen only when clinical suspicion

›Amphetamines and sympathomimetics

›Cocaine

06Diagnostic Tests/dt50

Scoring Systems

›Heat illness severity framing

›Heat exhaustion criteria cluster

›Heat exposure history

›Weakness

›Dizziness

›Nausea or vomiting

›Preserved mental status

›Heat stroke criteria cluster

›Core temperature >=40 C

›CNS dysfunction

›Exertional heat illness staging concept

›Mild with cramps and fatigue

›Moderate with collapse or persistent vomiting

›Severe with CNS dysfunction or organ injury

›Orthostatic vital sign interpretation

›Standing HR increase >=30 beats/min suggests volume depletion

›Older adults may have blunted HR response

›SBP drop >=20 mmHg suggests orthostatic hypotension

›Consider medications and autonomic dysfunction

MRI

›MRI brain indications

›Persistent neurologic deficit after cooling and correction

›Stroke evaluation

›Unexplained seizure

›Structural lesion evaluation

›MRI heat illness role limitations

›Not routine for uncomplicated heat exhaustion

›Time and access limitations in acute care

›CT head indications

›Altered mental status not resolving with cooling and rehydration

›Intracranial hemorrhage exclusion

›Focal neurologic deficit

›Acute stroke evaluation

›CT abdomen and pelvis indications

›Severe abdominal pain

›Alternate diagnosis evaluation

›CT heat illness role limitations

›Not routine for uncomplicated heat exhaustion

›Radiation and contrast risk in AKI

Ultrasound

›Point-of-care ultrasound use cases

›IVC and volume status adjunct

›Collapsible IVC suggests hypovolemia

›Cardiac POCUS when shock or chest symptoms

›Pericardial effusion exclusion

›LV function estimation

›Lung POCUS when dyspnea

›B lines for pulmonary edema

›Consolidation for pneumonia

›Ultrasound limitations

›Operator dependent

›Volume status estimation imperfect

07Disposition/dispo30

Observation vs discharge criteria

›Disposition framework

›ED observation criteria

›Persistent symptoms after initial cooling and fluids

›Ongoing orthostatic hypotension

›Inability to tolerate oral intake

›Significant electrolyte abnormality requiring recheck

›Discharge criteria

›Symptom resolution

›Normal mental status

›Stable vital signs without orthostasis

›Tolerating oral fluids

›Reliable follow-up and safe environment

›Admission criteria

›Suspicion of heat stroke

›Any CNS dysfunction

›Acute kidney injury

›Rising creatinine or oliguria

›Rhabdomyolysis requiring IV fluids

›Markedly elevated CK with symptoms

›Severe electrolyte disturbance

›Sodium <125 mmol/L or symptomatic hyponatremia

›Potassium >=6.0 mmol/L or ECG changes

›Significant comorbidity

›Heart failure or severe CAD

›Advanced CKD

›Transfer criteria

›Need for intensive cooling resources not available

›Exertional heat stroke with immersion need

›Multi-organ dysfunction

›ICU level care need

08Treatment/t80

Cooling and environment

›Cooling strategy

›Immediate environment changes

›Shade or cooled space

›Remove excess clothing and equipment

›Evaporative cooling

›Tepid water mist

›Fan directed airflow

›Wet towels with airflow

›Re-wet frequently

›Ice pack placement

›Axillae

›Skin protection barrier

›Groin

›Skin protection barrier

›Neck

›Skin protection barrier

›Cooling targets

›Symptom improvement

›Reduced dizziness

›Temperature <38 C if elevated

›Avoid overshoot hypothermia

Fluids and electrolytes

›Oral rehydration preferred when safe

›Oral rehydration solution

›Sodium containing fluids for heavy sweating

›Small frequent sips

›Nausea mitigation

›Avoid water-only overcorrection in prolonged exertion

›Hyponatremia risk

›IV isotonic fluid resuscitation when needed

›0.9% saline IV bolus 10-20 mL/kg

›Reassess symptoms and vitals after each bolus

›Orthostasis improvement

›Additional bolus 10 mL/kg if ongoing hypovolemia

›Lung exam monitoring for overload

›Balanced crystalloid alternative per local practice

›Hyperchloremia mitigation rationale

›Electrolyte correction principles

›Hyponatremia evaluation before hypertonic therapy

›If seizure or severe neurologic symptoms, treat per hyponatremia emergency pathway

›Hypokalemia correction when present

›Oral potassium preferred if mild and tolerating PO

›Recheck potassium after replacement

›IV potassium if severe or unable to tolerate PO

›Cardiac monitoring for IV replacement

›Nausea and vomiting control

›Ondansetron ODT 4 mg

›Repeat 4 mg after 8 hours as needed

›QT prolongation risk review

›Ondansetron IV 4 mg

›Repeat 4 mg after 6-8 hours as needed

›QT prolongation risk review

Exertional cramps and pain

›Heat cramps management

›Oral electrolyte solution

›Sodium replacement emphasis

›Gentle stretching of affected muscle

›Stop exertion until resolved

›Magnesium only when deficiency suspected

›Routine magnesium not consistently beneficial

›Analgesia options

›Acetaminophen 650 mg PO

›Fever treatment not primary mechanism

›NSAID caution

›AKI risk in dehydration

Complications and escalation

›Rhabdomyolysis management when suspected

›Isotonic fluids titrated to urine output

›Urine output >=1 mL/kg/hour target in significant rhabdomyolysis

›Pulmonary edema monitoring in at-risk patients

›Hyperkalemia management pathway if present

›ECG monitoring

›Calcium therapy if ECG changes

›If heat stroke cannot be excluded, immediate heat stroke protocol

›Rapid active cooling to target 38-39 C

›Ice water immersion preferred for exertional heat stroke when feasible

›ICU consult

›Multi-organ dysfunction monitoring

›Evidence notes for heat illness management

›Rapid cooling is primary determinant of outcome in heat stroke

›Class I recommendation based on consensus in emergency and wilderness medicine

›Oral rehydration effective for mild heat illness with intact mental status

›ACEP Level C style recommendation based on consensus and small studies

09Special Populations/sp28

Pregnancy

›Pregnancy considerations

›Maternal hyperthermia risks

›Fetal distress concern with sustained high temperature

›Hydration strategy

›Lower threshold for IV fluids if vomiting

›Avoid hypotonic fluids in hyponatremia risk

›Fetal assessment triggers

›If viable gestation and significant symptoms, obstetric consult

›If abdominal pain or vaginal bleeding, urgent obstetric evaluation

Geriatric

›Older adult considerations

›Impaired thermoregulation

›Reduced sweating

›Medication drivers

›Diuretics and anticholinergics

›Volume assessment pitfalls

›Blunted tachycardia response

›Fluid resuscitation caution

›Heart failure risk

›Lung exam and oxygenation monitoring

Pediatrics

›Pediatric considerations

›Higher surface area to mass ratio

›Faster heat gain

›Weight-based fluids

›0.9% saline 10-20 mL/kg bolus

›Reassess perfusion and mental status

›Return to play guidance

›Same-day return avoidance after heat exhaustion episode

›Graduated acclimatization plan

10Background/b33

Epidemiology

›Epidemiology snapshot

›Heat exhaustion common in hot weather and exertional settings

›Peak incidence during heat waves

›Risk concentration

›Athletes early in season

›Outdoor workers

›Older adults and chronic disease patients

›Recurrence risk

›Prior heat illness increases future risk

Pathophysiology

›Heat exhaustion mechanisms

›Heat production exceeds heat dissipation

›High ambient temperature

›High humidity reduces evaporative cooling

›Dehydration and salt loss

›Reduced plasma volume

›Reduced cardiac output reserve

›Splanchnic vasoconstriction and gut ischemia contribution

›Nausea and vomiting

›Progression pathway

›Persistent heat stress leading to heat stroke if untreated

Therapeutic Considerations

›Cooling rationale

›Lower core temperature reduces physiologic strain

›Improved cardiovascular stability

›Evaporative cooling effectiveness

›Works best with airflow and low humidity

›Fluid therapy rationale

›Isotonic fluids restore intravascular volume

›Improved orthostatic tolerance

›Sodium replacement when heavy sweating

›Prevent exercise-associated hyponatremia

›Return to exertion rationale

›Heat acclimatization takes 7-14 days

›Graded exposure reduces recurrence risk

11Patient Discharge Instructions/pdi26

copy discharge instructions

›Heat exhaustion discharge instructions

›Rest in a cool place for 24 hours

›Avoid strenuous activity for at least 24 hours

›Hydration plan

›Drink fluids regularly

›Use electrolyte drinks if sweating heavily

›Heat avoidance plan

›Avoid midday heat

›Wear light breathable clothing

›Gradual return to activity

›Resume exercise slowly over several days

›Stop activity if symptoms recur

›Return to ED immediately for red flags

›Confusion

›Fainting

›Seizure

›Worsening headache

›Persistent vomiting

›Chest pain

›Trouble breathing

›Not peeing for 8 hours

›Dark tea-colored urine

›Fever or very high temperature

›Follow-up plan

›Primary care follow-up within 24-72 hours if symptoms not fully resolved

›Same-day follow-up if abnormal labs were present

12References/r12

Guidelines and evidence sources

›Heat illness references

›Wilderness Medical Society clinical practice guidelines for prevention and treatment of heat illness

›Cooling and rehydration recommendations

›CDC heat illness clinical guidance materials

›Heat exhaustion vs heat stroke differentiation

›American College of Sports Medicine position statements on exertional heat illness

›Return to play and acclimatization guidance

›Emergency medicine and critical care references

›ACEP clinical policy style principles for hyperthermia and related emergencies

›Consensus level recommendations for cooling and supportive care

›Review literature on exertional heat stroke cooling modalities

›Ice water immersion superiority for rapid cooling in exertional heat stroke

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Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

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