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ModifiedCurativePolicy CHP-IP-2026-164

Acute Heat Stroke Inpatient and Level-of-Care Coverage Policy

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Medical-necessity criteria for acute inpatient admission, observation, outpatient management, intensive care, intermediate care, medical-surgical care, continued stay, and discharge readiness for exertional and classic heat stroke in Curative commercial members of all ages.

Policy Summary

PayerCurative

PolicyAcute Heat Stroke Inpatient and Level-of-Care Coverage Policy

Policy CodePolicy CHP-IP-2026-164

Change TypeModified — coding labels clarified

Effective DateN/A

Next Review DateN/A

Key ActionDocument the highest core rectal temperature and temperatures over time.

SourceLink

POLICY UPDATE CHANGES

This version supersedes Version 5.4.1, approved November 2, 2026, and is identified as unchanged between versions.

The FY 2026 ICD-10-CM labels are clarified so that T67.01XA is heatstroke and sunstroke and T67.02XA is exertional heatstroke.

All agesApplicable population

24–48 hoursObservation duration

24–72 hoursOrgan injury window

Daily ICU / 48h non-ICUConcurrent review

>40°CUsual hyperthermia

39°CCooling-failure threshold

Medical Necessity and Level-of-Care Criteria

Initial acute inpatient admission

Acute inpatient admission for heat stroke is medically necessary when ALL of the following are met.

Inpatient admission

Clinical severity finding
- Neurologic heat-stroke finding: Central nervous system dysfunction with core temperature above 40°C at any time, or a history of heat exposure or exertion when field cooling lowered the temperature before measurement.GCS 14 or lower or confusion, delirium, seizure, or coma; usually temperature >40°C
- Persistent neurologic dysfunction: Central nervous system dysfunction persists after the core temperature is below 39°C.Core temperature <39°C

Policy Summary

PayerCurative

PolicyAcute Heat Stroke Inpatient and Level-of-Care Coverage Policy

Policy CodePolicy CHP-IP-2026-164

Change TypeModified — coding labels clarified

Effective DateN/A

Next Review DateN/A

Key ActionDocument the highest core rectal temperature and temperatures over time.

SourceLink

On This Page

Renal injury: Acute kidney injury or oliguria is present.Creatinine rise >=0.3 mg/dL or >=1.5 times baseline, or urine output <0.5 mL/kg/h for 6 hours

Muscle injury: CK is markedly elevated or myoglobinuria is present.CK >=5 times upper limit of normal or myoglobinuria

Hepatic or coagulation injury: Marked transaminase elevation, coagulopathy, thrombocytopenia, or other evidence of disseminated intravascular coagulation is present.AST/ALT >3 times upper limit of normal, INR >=1.5, platelets <100,000/µL, or other DIC evidence

Physiologic instability: Hemodynamic, respiratory, metabolic, or electrolyte instability is present.SBP <90 mm Hg after fluids, lactate >=4 mmol/L, SpO2 <90% on room air, potassium >=5.5 mmol/L, or glucose <60 mg/dL

Hospital-level service

Active cooling: Continued active cooling with continuous core-temperature monitoring is required.
IV fluids and serial testing: Intravenous fluids with serial CK, electrolytes, creatinine, liver tests, and coagulation studies are required.Testing at least every 12–24 hours
Enhanced monitoring: Continuous cardiac monitoring or frequent neurologic checks are required.Neurologic checks at least every 2 hours
Critical support: Seizure treatment, airway protection, or ventilatory support is required.
Advanced treatment: Blood products for coagulopathy or renal replacement therapy are required.

Observation or outpatient management

Observation, generally up to 24–48 hours, or outpatient management is appropriate when ANY of the following applies and no inpatient severity finding is present.

Lower-acuity management

Heat exhaustion or syncope: Heat exhaustion or heat syncope with normal mental status after cooling and normal kidney, liver, and coagulation tests.
Emergency department or outpatient care.
Rapidly recovered exertional heat stroke: Exertional heat stroke was cooled rapidly on site, mental status fully returned, initial laboratory tests are normal, and vital signs are stable.Repeat laboratory testing at about 24 hours
Observation; admit if organ injury appears.
Mild exertional CK elevation: CK elevation is mild and there is no kidney injury after exertion.CK <5 times normal
Outpatient follow-up with oral hydration.

Intensive care unit placement

Intensive care unit placement is appropriate when ANY of the following is present.

ICU criteria

Severe neurologic or airway impairment: GCS is 8 or lower, recurrent seizures occur, or intubation is needed.GCS <=8
Persistent hyperthermia: Core temperature remains at or above 39°C despite active cooling.>=39°C despite cooling
Hemodynamic or electrical instability: Hypotension requires vasopressors after fluid resuscitation or a ventricular arrhythmia is present.
Major organ failure: DIC, acute liver failure with encephalopathy, ARDS, or kidney injury requiring renal replacement therapy is present.Acute liver failure includes INR >=1.5 with encephalopathy

Step-down or intermediate care

Step-down or intermediate care is appropriate when ANY of the following is present and no ICU criterion is met.

Intermediate-care criteria

Residual encephalopathy is present with a protected airway.GCS 9–13
Renal or muscle injury monitoring: Rising CK or acute kidney injury requires hourly urine-output and frequent electrolyte monitoring.Hourly urine output
Coagulation or hepatic monitoring: Coagulopathy or rising transaminases requires frequent laboratory checks.Laboratory checks every 6–12 hours

Medical-surgical unit

Medical-surgical placement is appropriate when ANY of the following describes the patient and no higher-level criterion is met.

Medical-surgical criteria

Improving laboratory abnormalities: The patient is normothermic with mental status at baseline, abnormal CK, creatinine, or liver tests are improving, and intravenous fluids are still needed.
Stabilized classic heat stroke: An older adult with classic heat stroke has stabilized but requires treatment of a precipitating condition such as infection or dehydration.

Discharge readiness

Discharge from acute inpatient care is appropriate when ALL of the following are met.

Temperature and mental status: Temperature is below 38.0°C for at least 24 hours and mental status is at baseline.<38.0°C for >=24 hours
Laboratory recovery: CK, creatinine, liver tests, and coagulation studies are normal or clearly improving, with no renal replacement therapy.
Functional and oral intake recovery: The patient tolerates oral fluids and diet and ambulates at baseline.
Exertional heat stroke plan: For exertional heat stroke, a written graded return-to-activity plan, follow-up, and repeat laboratory testing are arranged.
Classic heat stroke safety plan: For classic heat stroke, a cool living environment, hydration plan, and review of medications that impair heat tolerance are documented.
Examples include diuretics and anticholinergics.

Continued acute inpatient stay

Continued acute inpatient stay is medically necessary when ANY of the following is documented at concurrent review.

Continued-stay criteria

Persistent neurologic injury: Persistent encephalopathy or seizures continue.
Renal or muscle deterioration: CK is rising, kidney injury is worsening, or renal replacement therapy is needed.
Worsening hepatic or coagulation injury: Liver injury or coagulopathy is worsening.May peak 24–72 hours after the event
Ongoing critical support: Ventilatory or vasopressor support remains necessary.
Acute complication: A complication requiring acute treatment, such as aspiration pneumonia or compartment syndrome, is present.

This policy addresses acute inpatient, observation, and level-of-care criteria for exertional and classic (nonexertional) heat stroke. Heat exhaustion and heat cramps without central nervous system dysfunction, malignant hyperthermia, neuroleptic malignant syndrome, and serotonin syndrome are outside the scope of this policy.

Heat exhaustion, heat cramps, or heat syncope with normal mental status and normal laboratory tests after treatment do not meet inpatient medical-necessity criteria. Emergency department or outpatient care is appropriate; an admission request in this circumstance is referred for physician review.

Continued acute inpatient days solely while awaiting placement after discharge readiness criteria are met do not meet acute inpatient criteria when no acute hospital-level service is being delivered. Active discharge planning is required, and days already authorized are not retroactively denied.

Days used for custodial care, family or provider convenience, or scheduling non-urgent tests or consultations that can safely be completed at a lower level of care or after discharge are not medically necessary at the acute inpatient level.

Diagnosis, DRG, Revenue, and Clinical Coding References

ICD-10-CM: heatstrokeICD-10

T67.01XA	Heatstroke and sunstroke
T67.02XA	Exertional heatstroke
T67.09XA	Other heatstroke

ICD-10-CM: common complications (secondary)ICD-10

M62.82	Rhabdomyolysis
N17.9	Acute kidney failure, unspecified
D65	Disseminated intravascular coagulation
K72.00	Acute and subacute hepatic failure without coma

MS-DRG (FY 2027 v44)MS-DRG

922	MS-DRG 922, FY 2027 v44
923	MS-DRG 923, FY 2027 v44

Revenue codesRevenue

0120	Revenue code
0200	Revenue code
0206	Revenue code
0250	Revenue code
0300	Revenue code
0762	Revenue code

FY 2026 ICD-10-CM Heat Stroke CodesICD-10

T67.01XA	Heatstroke and sunstroke
T67.02XA	Exertional heatstroke

Core temperature and neurologic dysfunction

TemperatureUsually above 40°C; core temperature above 40°C at any time supports the finding.

Neurologic thresholdGlasgow Coma Scale 14 or lower, or confusion, delirium, seizure, or coma.

History-based diagnosisA history of heat exposure or exertion may substitute when field cooling lowered the temperature before measurement.

Persistent dysfunctionCentral nervous system dysfunction that persists after the core temperature is below 39°C is a severity finding.

Acute kidney injury

Creatinine rise0.3 mg/dL or more above baseline, or 1.5 times baseline or more.

Urine outputBelow 0.5 mL/kg/h for 6 hours.

Clinical findingEither the creatinine or urine-output threshold supports acute kidney injury or oliguria.

Rhabdomyolysis

Creatine kinaseAt least 5 times the upper limit of normal.

MyoglobinuriaPresence of myoglobinuria supports rhabdomyolysis.

Qualifying findingEither marked CK elevation or myoglobinuria meets the listed muscle-injury threshold.

Hepatic, coagulation, and platelet injury

TransaminasesAST or ALT above 3 times the upper limit of normal.

CoagulationINR 1.5 or higher.

PlateletsBelow 100,000/µL.

DICOther evidence of disseminated intravascular coagulation also qualifies.

Physiologic instability

Blood pressureSystolic blood pressure below 90 mm Hg after initial fluids.

Lactate4 mmol/L or higher.

Oxygen saturationSpO2 below 90% on room air.

Potassium5.5 mmol/L or higher.

GlucoseBelow 60 mg/dL.

ICU temperature threshold

Core temperatureAt or above 39°C despite active cooling.

Recurrent riseA recurrent rise in core temperature is also a red flag requiring escalation.

ResponseIntensify cooling and escalate to ICU when the temperature remains at or above 39°C despite cooling.

Severe neurologic or airway impairment

Glasgow Coma Scale8 or lower.

SeizuresRecurrent seizures.

AirwayNeed for intubation or airway protection, including airway compromise.

Required responseRapid response or ICU transfer is indicated for seizure, GCS 8 or lower, or airway compromise.

Usual hyperthermia associated with exertional heat stroke

Temperature referenceUsually above 40°C.

MeasurementThe reference is a rectal temperature.

Clinical featuresExertional heat stroke is characterized by central nervous system disturbances with this degree of hyperthermia.

Cooling failure ICU criterion

Cooling targetReach about 39°C with active cooling.

Failure criterionFailure to reach about 39°C despite cooling is an ICU criterion.

Cooling methodRapid whole-body cooling, preferably ice-water immersion, is identified as the primary treatment.

Review, Documentation, and Adverse Determination Requirements

Denial Risk

Physician Review Required for Adverse Determinations

Automated systems and non-physician clinical reviewers may approve a request in full or in part but may not issue an adverse determination. Route requests that do not meet criteria to a licensed physician of the same or similar specialty, after offering the requesting provider a peer-to-peer discussion; the reviewing physician must also meet applicable licensure, specialty, and medical-director requirements for the plan's situs state.

Documentation Required

Continued-Stay Review

Apply concurrent review to each continued-stay period. Days already authorized are not retroactively denied, and the expected length of stay is a planning benchmark—not a limit on covered days.

Review each continued-stay period under the applicable criteria.
Do not retroactively deny previously authorized days.
Use the expected length of stay for planning, not as an automatic coverage limit.

Documentation Required

Document Heat Exposure and Cooling History

Document whether the presentation is exertional or classic, the duration of heat exposure, the time to cooling, and the cooling method used.

Documentation Required

Document the Temperature Record

Document the highest measured core rectal temperature and serial temperature measurements over time.

Documentation Required

Document Serial Neurologic Status

Document serial neurologic examinations and Glasgow Coma Scale measurements over time.

Documentation Required

Document Serial Laboratory Monitoring

Document serial laboratory monitoring, including CK, creatinine, electrolytes, liver tests, coagulation studies, platelets, lactate, and urinalysis.

Documentation Required

Document Level-of-Care and Discharge Rationale

Document the rationale for the level of care at each review and include the discharge plan, including return-to-activity or home-safety planning.

Documentation Required

Support the Requested Scope

The medical record must support the requested quantity, units, or duration. If the requested scope exceeds what the documentation supports, only the unsupported increment is subject to review.

Denial Risk

Lower-Acuity Heat Illness Submitted for Inpatient Admission

Heat exhaustion, heat cramps, or heat syncope with normal mental status and normal laboratory tests after treatment are appropriate for emergency department or outpatient care and do not meet inpatient criteria. Refer an admission request in this circumstance for physician review; it is not denied by an automated system or non-physician reviewer.

Denial Risk

Recovered Patient Kept as Inpatient

A patient with exertional heat stroke who has fully recovered after rapid on-site cooling and has normal laboratory tests at approximately 24 hours supports observation rather than continued inpatient care.

Denial Risk

Awaiting Post-Acute Placement

Continued acute inpatient days solely while awaiting placement in skilled nursing, rehabilitation, long-term acute care, behavioral health, or home services are not supported after discharge readiness criteria are met and no acute hospital-level service is being delivered. Refer for physician review and active discharge planning; days already authorized are not retroactively denied.

Denial Risk

Custodial or Convenience-Based Inpatient Days

Days used for custodial care, family or provider convenience, or scheduling non-urgent tests or consultations that could safely occur at a lower level of care or after discharge are not medically necessary at the acute inpatient level. Refer the request for physician review.

Denial Risk

Unsupported Quantity or Duration

When the service meets criteria but the requested quantity, units, or duration exceed what the documentation supports, approve the supported portion and subject only the unsupported increment to adverse determination review.

Clinical Background

Heat stroke is a medical emergency characterized by central nervous system dysfunction and marked hyperthermia, usually with a core rectal temperature above 40°C. Diagnosis may rely on the history and neurologic findings when field cooling lowered the temperature before arrival. Rapid whole-body cooling, preferably cold-water immersion, is the key intervention; rhabdomyolysis, acute kidney injury, hepatic injury, disseminated intravascular coagulation, respiratory failure, and electrolyte abnormalities may evolve over 24–72 hours.

Key Clinical Definitions and Planning Terms

Heat stroke

Core conditionCentral nervous system dysfunction with hyperthermia.

Neurologic manifestationsConfusion, delirium, seizure, or coma.

TemperatureUsually a rectal temperature above 40°C.

ContextOccurs during or after heat exposure or exertion.

Heat exhaustion

Primary featureInability to continue activity in the heat.

TemperatureGenerally below 40°C.

Neurologic statusNo significant central nervous system dysfunction.

Expected length of stay

PurposeA planning benchmark for an uncomplicated course.

Coverage effectIt is not a limit on covered days.

Review implicationContinued inpatient care is determined by ongoing acute conditions or hospital-level service needs.

Exertional heat stroke

SeverityA life-threatening condition.

Neurologic disturbanceCentral nervous system disturbances.

HyperthermiaUsually above 40°C rectal temperature.

Pre-hospital coolingA history-based diagnosis may be accepted when cooling lowered the temperature before measurement.