emergency & critical caredecision rule

PECARN Pediatric Head Injury Rule

PECARN identifies children with minor head trauma at very low risk of clinically important traumatic brain injury (ciTBI), enabling safe reduction of CT imaging and associated radiation exposure. Uses age-stratified algorithms for children <2 years and ≥2 years.

inputs

<24 months uses under-2 algorithm; ≥24 months uses the ≥2 algorithm
months

✓ when to use

Apply to children <18 years presenting to the ED with head trauma and GCS 14–15. The rule stratifies into three risk tiers: CT recommended, observation vs CT (shared decision), and CT not recommended. The primary goal is reducing unnecessary CT scans and radiation exposure in children while maintaining safety.

✗ when not to use

Not applicable for GCS ≤13 (CT indicated regardless), penetrating trauma, known bleeding disorders, ventricular shunts, or trivial mechanism with no signs/symptoms. The intermediate-risk group requires clinical judgement — PECARN provides a framework for shared decision-making, not a rigid mandate.

clinical pearls

  • PECARN is age-stratified because the predictors of ciTBI differ between infants and older children. <2 years: palpable skull fracture and 'not acting normally per parent' are key. ≥2 years: headache, vomiting, and signs of basilar skull fracture are used instead.
  • The intermediate-risk group is where clinical skill matters most. Factors favouring observation over CT include: isolated finding, improving symptoms, experienced clinician, reliable parents who can monitor, and proximity to hospital for return.
  • Parental assessment ('not acting normally') is a validated predictor in children <2 years. Parents know their child — if they say the child is not behaving normally, take it seriously even if your clinical exam is unremarkable.
  • PECARN addresses clinically important TBI (ciTBI), defined as death, neurosurgery, intubation >24h, or hospitalisation ≥2 nights for TBI. It does NOT address all CT-identified abnormalities — some children in the 'low-risk' group will have minor CT findings that don't change management.
  • The radiation dose from a paediatric head CT is roughly 2–4 mSv. While individual risk is small, the lifetime cancer risk from radiation is higher in children. PECARN enables evidence-based reduction in unnecessary scanning.

related tools

gcsConsciousness assessmentcanadian-ct-headAdult head injury imaging rule