PECARN 2009

PECARN Pediatric Head Injury Rule Calculator

Age-stratified decision support for CT imaging after pediatric head trauma. Identifies children at very low risk of clinically important traumatic brain injury (ciTBI).

Patient Age

Select the age group to load the appropriate PECARN rule.

Step 1 High-Risk Predictors. any present → CT recommended

If any of these are checked, CT is recommended regardless of Step 2.

Step 2 Intermediate Predictors. any present (Step 1 negative) → observation vs CT

Applies only when all Step 1 predictors are absent.

Your data never leaves this device. No accounts. No servers. No tracking.

Frequently Asked Questions About PECARN & Pediatric Head Injury

The PECARN (Pediatric Emergency Care Applied Research Network) head injury rule is an evidence-based clinical decision tool published by Kuppermann et al. in The Lancet (2009) to identify children at very low risk of clinically important traumatic brain injury (ciTBI) after blunt head trauma.

The rule applies to children under 18 years of age who present within 24 hours of blunt head trauma with a GCS of 14–15. It uses two separate decision rules stratified by age: one for children under 2 years and one for children aged 2–18 years. It was derived from a prospective cohort of over 42,000 children across 25 emergency departments in the PECARN network.

ciTBI (clinically important traumatic brain injury) is defined in the PECARN study as death from TBI, neurosurgical intervention, intubation >24 hours for TBI, or hospital admission ≥2 nights for TBI on CT. This composite outcome captures injuries that actually require intervention, as opposed to incidental CT findings that may be managed conservatively.

ciTBI matters because CT scanning delivers ionizing radiation that is particularly harmful in children (lifetime cancer risk is higher). The PECARN rule identifies children with a ciTBI risk below 0.02% (age <2) or below 0.05% (age 2–18) in whom CT can be safely avoided, which translates to avoiding thousands of unnecessary scans annually.

For Tier 2 (intermediate-risk) patients with a ciTBI risk of approximately 0.9%, the PECARN authors recommend individualized decision-making based on clinical judgment. Factors favoring CT include: multiple intermediate-risk predictors present, worsening symptoms over the observation period, prior CT imaging (radiation budget already spent), or parental preference after informed discussion of risks and benefits.

Factors favoring observation include: isolated single intermediate-risk predictor, symptoms stable or improving, young age (radiation risk is higher), and parental willingness to monitor. Observation typically means 4–6 hours of serial neurological assessments in the ED before discharge or admission decision. If symptoms worsen during observation, CT is indicated.

The PECARN study defined severe mechanism of injury as: motor vehicle crash (MVC) with patient ejection, death of another passenger, or rollover; pedestrian or bicyclist without helmet struck by a motorized vehicle; fall from a height greater than 3 feet (0.9 m) for children under 2 or 5 feet (1.5 m) for children aged 2–18; or the head being struck by a high-impact object.

Note that for children under 2, the fall height threshold is lower (3 ft) reflecting their greater vulnerability. Low-impact falls such as falling from a standing position or falling from furniture at normal seat height typically do not qualify as severe mechanisms, though the full clinical context should always be considered.

The PECARN rule was validated for children with blunt head trauma and a GCS of 14 or 15 presenting within 24 hours of injury. It should not be applied to children with: penetrating trauma, known brain tumors, pre-existing neurological conditions that make assessment unreliable, coagulopathy or bleeding disorders, or cases requiring immediate CT for hemodynamic instability.

Children with a GCS of 13 or below already meet the high-risk criterion (GCS ≤14) and CT is recommended regardless of other predictors. The rule is also not intended to replace clinical judgment. It is a decision support tool. A child who appears clinically unwell or whose trajectory is worrying may warrant CT even if the rule score suggests low risk.

In the original Kuppermann 2009 derivation/validation cohort, the PECARN rule demonstrated sensitivity of 100% for age <2 years and 96.8% for age 2–18 years for ciTBI. The negative predictive value (NPV) exceeds 99% in both age groups when all predictors are absent (Tier 3).

For the intermediate-risk group (Tier 2), the ciTBI risk is approximately 0.9%, meaning that even in this group the large majority of children do not have ciTBI. The very high NPV in the no-predictor group provides strong evidence for safely forgoing CT in Tier 3 patients, which represents approximately 25% of all children presenting with head trauma.