PECARN Pediatric Head CT Calculator

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PECARN uses separate criteria for children under 2 and children aged 2 and older. Select the group that matches the patient.
Altered mental status includes agitation, somnolence, repetitive questioning, or a GCS score of exactly 14. A GCS of 13 or lower is an exclusion criterion - those patients require CT regardless.
A palpable bony step-off, depression, or diastasis on examination of the skull.
Scalp hematomas away from the frontal region (parietal, temporal, or occipital) carry more risk than frontal hematomas in children under 2.
For children under 2, only loss of consciousness lasting 5 seconds or more is counted as an intermediate risk factor.
Severe mechanisms include: fall from more than 0.9 m (about 3 feet), struck by a high-speed or high-impact object, motor vehicle collision with ejection, rollover, or a fatality in the vehicle, or an unhelmeted cyclist or pedestrian struck by a motor vehicle.
Parental or caregiver concern that the child is not behaving normally, beyond what can be directly observed in the ED.
Risk categoryVery low risk - CT not recommended
Very low risk

PECARN-derived risk stratum for clinically important TBI

Estimated ciTBI risk<0.02%
CT recommendationCT not recommended - discharge with head injury advice
High-risk factors present0
Intermediate-risk factors present0
0 high-risk factors
Very low / Intermediate<1High risk1+

Very low risk: CT is not recommended. Estimated ciTBI risk is <0.02%.

  • No high-risk or intermediate-risk PECARN factors are present. The ciTBI rate in this group was <0.02% for children under 2 - the risk of CT radiation may outweigh any benefit from imaging.
  • The PECARN authors recommend discharge with written head injury advice and clear return precautions rather than CT scanning in this group.
  • This tool applies only to children with GCS 14-15 presenting within 24 hours of blunt head trauma. Children with GCS 13 or lower, penetrating trauma, VP shunts, bleeding disorders, or presentation over 24 hours after injury require CT regardless of PECARN score.

Next stepDischarge with head injury instructions. Advise the family to return if the child develops worsening headache, repeated vomiting, unusual sleepiness, seizure, or any behavioral change.

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