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Risk-stratifies children with minor blunt head trauma for clinically important traumatic brain injury (ciTBI) using the age-specific PECARN decision rule (Kuppermann 2009). Two separate rules apply for children under 2 years and children 2 years and older; the risk of ciTBI is < 0.02–0.05% when none of the rule's predictors are present.
Under 2 years: 0 of 6 predictors present (altered mental status, palpable skull fracture, non-frontal scalp hematoma, LOC ≥ 5 s, not acting normally, dangerous mechanism) → very low risk (< 0.02%). Age ≥ 2 years: 0 of 6 predictors present (altered mental status, basilar skull fracture signs, vomiting, severe headache, LOC, dangerous mechanism) → very low risk (< 0.05%).
A child with NONE of the rule's predictors for their age group has a < 0.02% (under 2 years) or < 0.05% (2 years and older) risk of clinically important traumatic brain injury and does not require CT.
The PECARN (Pediatric Emergency Care Applied Research Network) rule (Kuppermann 2009) was derived and validated on 42,412 children with minor blunt head trauma (GCS 14–15). For children under 2 years, the six predictors are altered mental status (including GCS < 15), palpable skull fracture, non-frontal scalp hematoma, loss of consciousness ≥ 5 seconds, not acting normally per the parent, and a dangerous mechanism. For children 2 years and older the predictors are altered mental status, signs of basilar skull fracture, vomiting, severe headache, any loss of consciousness, and a dangerous mechanism. Children with none of the predictors have a ciTBI risk below 0.05% and can be managed without CT. A dangerous mechanism is a motor-vehicle crash with ejection, death of another passenger, or rollover; a pedestrian or cyclist (without a helmet) struck by a motorized vehicle; a fall from > 3 feet (under 2 years) or > 5 feet (2 years and older); or a head struck by a high-impact object.
Specialty
PediatricsCategory
PediatricsDifficulty
Basic
Estimated Time
30 seconds
Version
1.0
Last Updated
2026-08-16
Formula
Keywords
Normal Range
A child with NONE of the rule's predictors for their age group has a < 0.02% (under 2 years) or < 0.05% (2 years and older) risk of clinically important traumatic brain injury and does not require CT.
| Classification | Range |
|---|---|
Very low risk ciTBI < 0.02% (under 2 y) / < 0.05% (≥ 2 y); CT not indicated | 0 predictors |
Not very low risk ciTBI ≈ 0.9%; observation preferred over CT when isolated | 1 predictor |
Higher risk ciTBI risk substantially increased; CT indicated | ≥ 2 predictors |
Identifies children with minor blunt head trauma at very low risk of clinically important traumatic brain injury (ciTBI) using the age-specific PECARN decision rule (Kuppermann 2009) — separate predictor sets for children under 2 years and children 2 years and older.
If NONE of the predictors are present, the risk of ciTBI is < 0.02% (under 2 years) or < 0.05% (2 years and older) and CT is not indicated. If one predictor is present the risk is approximately 0.9% and observation is generally preferred over CT. If two or more predictors are present, the risk is substantially higher and CT is indicated.
The PECARN rule is one of the most extensively validated decision rules in pediatric emergency medicine, allowing clinicians to safely avoid head CT in a large proportion of children with minor head trauma while identifying those who need imaging.
A 14-month-old fell from a changing table (~2.5 feet) onto carpet. GCS 15, acting normally, no scalp hematoma, no LOC, no palpable fracture, no concerning mechanism.
Inputs:
PECARN (under 2 years) — very low risk; risk of clinically important TBI < 0.02%; CT not indicated; provide return precautions.
Death, the need for neurosurgery, intubation for more than 24 hours, or traumatic brain injury with a hospital stay of 2 or more nights.
In general, CT is recommended for children with two or more PECARN predictors, any high-risk predictor with substantial clinical concern, or deterioration during observation. Children under 3 months with any scalp hematoma are also generally scanned.
Disclaimer: This calculator is intended for educational and clinical decision support purposes only. The PECARN rule supports, but does not replace, clinical judgment; any child with clinical deterioration warrants CT regardless of the calculated risk.
Scoring consciousness impairment
Multi-system injury severity