PECARN calculator for pediatric head injury
Use the PECARN calculator for pediatric head injury after blunt head trauma to review age-specific predictors, separate very low from higher-risk patients, and support observation versus CT decisions.
Last reviewed: February 26, 2026
Clinical disclaimer
PECARN calculator quick read
- Use the PECARN calculator for pediatric head injury after blunt head trauma when you need a fast CT-versus-observation decision aid.
- Start by selecting the correct age cohort because the PECARN predictors differ for children younger than 2 years and those 2 years and older.
- High-risk findings usually support CT. Intermediate-risk cases often need observation, serial exams, and shared decision-making rather than automatic imaging.
- Do not apply PECARN to penetrating trauma, suspected abuse, unstable patients, or children with bleeding disorders.
PECARN stratifies children younger than 2 years separately.
Any GCS below 15 at assessment.
Agitation, somnolence, repetitive questioning, or slow response.
Battle sign, raccoon eyes, CSF leak, hemotympanum.
Any vomiting episodes after injury.
High-speed MVC, ejection/rollover, fall >5 ft, or struck by high-impact object.
How the PECARN calculator works
PECARN identifies children at very low risk of clinically important traumatic brain injury (ciTBI). It uses separate criteria for children younger than 2 years and for those 2 years and older. The tool classifies patients as very low risk (CT not recommended), intermediate risk (observe vs CT), or high risk (CT usually recommended).
Rapid bedside workflow
- Confirm blunt head trauma eligibility and verify there are no exclusion criteria before applying PECARN.
- Select age cohort (<2 years or >=2 years) and complete predictor review with the current bedside exam.
- Classify risk tier and decide observation versus CT using trajectory, comorbidities, and family discussion.
- During observation, repeat neurologic and symptom assessments at defined intervals.
- Escalate immediately for any deterioration regardless of initial risk category.
High-risk predictors
- <2 years: GCS < 15, altered mental status, palpable skull fracture.
- >=2 years: GCS < 15, altered mental status, signs of basilar skull fracture.
High-risk features generally support CT and urgent neuro evaluation.
Intermediate-risk predictors
- <2 years: non-frontal scalp hematoma, loss of consciousness >= 5 seconds, severe mechanism, not acting normally per parent.
- >=2 years: history of loss of consciousness, vomiting, severe mechanism, severe headache.
Intermediate risk supports observation or CT based on clinical course, risk factors, and shared decision-making.
Exclusions and limitations
- Do not use for penetrating trauma, suspected abuse, or known bleeding disorders.
- Children with unstable vitals, focal neurologic deficits, or seizures need individualized evaluation.
- PECARN does not replace serial exams; worsening symptoms always warrant reassessment.
Reassessment cadence during observation
- Intermediate-risk observation: serial neurologic checks in the same care block and before disposition.
- Post-intervention or symptom change: immediate repeat exam and predictor reassessment.
- Persistent stability over observation window: finalize disposition with explicit return precautions.
Red flags and escalation
- Persistent altered mental status, new focal deficits, or seizures.
- Signs of basilar skull fracture or expanding scalp hematoma.
- Repeated vomiting, severe headache, or deteriorating level of consciousness.
- High-risk mechanisms with concerning clinical trajectory.
Shift handoff checklist
- Age cohort, predictors present/absent, and current risk tier.
- Observation timeline, symptom trend, and serial neuro findings.
- Shared decision details around CT versus observation.
- Escalation triggers and return-precaution thresholds provided to caregivers.
Related calculators
- Pediatric Glasgow Coma Scale (pGCS) calculator — for serial neurologic scoring during head injury observation.
- Pediatric vital signs chart by age — to check age-based heart rate, respiratory rate, and blood pressure during reassessment.
- ED & Acute Care Tools
- Pediatric ED calculators hub
References
Frequently asked questions
PECARN has separate decision rules for children younger than 2 years and for those 2 years and older. Enter age to select the correct cohort.
No. PECARN was designed for blunt head trauma in the emergency setting. Penetrating trauma, suspected abuse, or children with bleeding disorders require individualized evaluation.
Severe mechanism includes high-speed MVC with ejection/rollover, death of another passenger, pedestrian or bicyclist without helmet struck by a motor vehicle, fall >3 ft (<2 years) or >5 ft (>=2 years), or head struck by a high-impact object.
Not necessarily. PECARN recommends observation versus CT based on clinical course, risk factors, and shared decision-making. Many children can be safely observed if they remain stable.
Document serial neurologic exams, symptom trend, final risk interpretation, and explicit return precautions. Clear documentation is key when CT is deferred.