PECARN Pediatric Head Injury Rule Calculator (CT Decision)
Apply the PECARN pediatric head trauma rule for children with GCS 14–15 — separate branches for under 2 and age 2+ — to see if CT, observation or no CT is advised, with ciTBI risk.
How it works
Under 2: GCS 14 / altered mental status or palpable skull fracture → CT (ciTBI 4.4%); else non-frontal scalp haematoma, LOC ≥ 5 s, severe mechanism or not acting normally → observation vs CT (0.9%); else no CT (< 0.02%). Age 2+: GCS 14 / altered mental status or signs of basilar skull fracture → CT (4.3%); else any LOC, vomiting, severe mechanism or severe headache → observation vs CT (0.9%); else no CT (< 0.05%).
The PECARN rules (Kuppermann et al., Lancet 2009) were derived and validated in more than 42,000 children with minor blunt head trauma presenting within 24 hours with a GCS of 14 or 15. They identify children at very low risk of clinically important traumatic brain injury (death, neurosurgery, intubation over 24 hours or hospital stay of 2 nights or more for the injury), in whom CT can be avoided, with a negative predictive value above 99.9%. For the middle group the choice between observation and CT depends on clinician experience, several versus isolated findings, worsening symptoms, age under 3 months and parental preference.
Worked example
A 6-year-old vomited once after falling off a playground swing (about 1 m), with GCS 15, no loss of consciousness, no headache and no signs of skull fracture. Vomiting puts the child in the middle group: Observation versus CT, with a ciTBI risk of about 0.9%.
Frequently asked questions
What is clinically important TBI in PECARN?
A brain injury leading to death, neurosurgery, intubation for more than 24 hours, or hospital admission for two nights or more because of the head injury.
What should I do in the observation-versus-CT group?
Observation for a few hours in the emergency department is often reasonable, especially with an isolated finding. CT is favoured with multiple findings, worsening symptoms, age under 3 months or a less experienced clinician.
Does PECARN apply to every child with a head injury?
It applies to children under 18 seen within 24 hours of blunt head trauma with a GCS of 14 or 15. It excludes trivial mechanisms, penetrating trauma, known brain tumours, bleeding disorders, shunts and prior neurological disease.
How accurate are the PECARN rules?
In validation the very-low-risk criteria missed almost no children with clinically important brain injury (sensitivity about 97–100%, negative predictive value above 99.9%), and later external validations confirmed this.
Related calculators
Clinical decision tool for education and for use by trained clinicians alongside clinical judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.