PECARN head injury rule (< 2 years)
Need for CT after minor head trauma in children under 2 (GCS 14–15)
Sources last checked: 2026-10-13
PECARN head injury rule (< 2 years)
Need for CT after minor head trauma in children under 2 (GCS 14–15)
Risk of clinically important TBI < 0.02 % in the derivation cohort.
Only for children < 2 years presenting within 24 h of blunt head trauma with GCS 14–15. Not for penetrating trauma, known brain tumour, bleeding disorders, ventricular shunts, or suspected non-accidental injury — the rule does not cover these.
Interpretation
| No predictor — PECARN: CT not recommended | Risk of clinically important TBI < 0.02 % in the derivation cohort. |
|---|---|
| Intermediate — observation versus CT | Risk ≈ 0.9 %. PECARN leaves the choice between observation and CT to clinical factors: number of findings, worsening symptoms, age < 3 months, physician experience, parental preference. |
| High risk — PECARN: CT recommended | Risk of clinically important TBI ≈ 4.4 %. |
What is the PECARN head injury rule (< 2 years)?
The PECARN rules were derived and validated by Kuppermann and colleagues in 2009 in more than 42,000 children with minor blunt head trauma (GCS 14–15) across 25 North American emergency departments. The rule for children under 2 years identifies those at very low risk of clinically important traumatic brain injury in whom CT can be avoided; in validation it missed no case.
When to use it
- Children under 2 years within 24 h of blunt head trauma with GCS 14–15
- Deciding between CT, observation and discharge
- Explaining radiation-risk trade-offs to parents
When not to use it
- Penetrating trauma, known brain tumour, pre-existing neurological disorder, bleeding disorder or ventricular shunt
- Suspected non-accidental injury
- GCS ≤ 13 — these children are outside the low-risk population the rule addresses
How it is calculated
High risk (PECARN: CT recommended): GCS 14 or other altered mental status, OR palpable skull fracture. Intermediate (observation vs CT): occipital/parietal/temporal scalp haematoma, OR LOC ≥ 5 s, OR severe mechanism, OR not acting normally per parent. Severe mechanism: motor-vehicle crash with ejection, rollover or death of another passenger; pedestrian or unhelmeted cyclist struck by a motorised vehicle; fall > 0.9 m (3 ft); head struck by a high-impact object. No predictor: PECARN does not recommend CT.
Clinical pearls and limitations
- Only for children < 2 years presenting within 24 h of blunt head trauma with GCS 14–15. Not for penetrating trauma, known brain tumour, bleeding disorders, ventricular shunts, or suspected non-accidental injury — the rule does not cover these.
- A frontal scalp haematoma is not a predictor; occipital, parietal or temporal haematomas are.
- Kuppermann 2009 lists age < 3 months among the factors favouring CT in the intermediate group.
- A prospective Australian and New Zealand study (Babl 2017) found PECARN more sensitive than CATCH and CHALICE.
Frequently asked questions
When does a toddler need a CT after a fall?
Under PECARN, CT is recommended for GCS 14, other altered mental status or a palpable skull fracture. With intermediate findings PECARN leaves observation versus CT to clinical factors; with no predictor, CT is not recommended.
What counts as a severe mechanism in under-2s?
Vehicle crash with ejection, rollover or a fatality; pedestrian or unhelmeted cyclist hit by a vehicle; fall from more than 0.9 m; or a high-impact object to the head.
Is PECARN used in Europe?
Yes, it is widely used and has been validated outside North America, though national head-injury guidelines (e.g. NICE) use their own criteria.
Evidence and guidelines
- Primary source: Kuppermann N et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet 2009;374(9696):1160-1170.
- Babl FE et al. Accuracy of PECARN, CATCH, and CHALICE head injury decision rules in children: a prospective cohort study. Lancet 2017;389(10087):2393-2402.
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
Ask Medelix about the PECARN head injury rule (< 2 years)Related calculators
Embed this calculatorFree to use on your website, intranet or teaching page. Copy the code below.
<iframe src="https://medelix.ai/en/embed/pecarn-head-under-2" title="PECARN head injury rule (< 2 years) – Medelix" width="100%" height="620" style="border:0;max-width:720px" loading="lazy"></iframe>
<p><a href="https://medelix.ai/en/calculators/pecarn-head-injury-under-2">PECARN head injury rule (< 2 years) calculator by Medelix</a></p>For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.