Pediatric head injury · Clinical score
The PECARN pediatric head-injury rule is the most-validated decision tool for deciding whether a child with minor head trauma needs a CT scan. It covers two age bands — under 2 years, and 2 years and older — and was derived from a prospective cohort of more than 40,000 children. The band breakdown below unifies both age groups into the same outcome table, and the tool beneath it applies the correct criteria once you pick the child’s age.
PECARN applies only to children with minor head trauma who present within 24 hours of injury and have a normal mental status on arrival (GCS 14–15). Two parallel decision rules share the same structural form — “any high-risk factor present → consider CT; none present → CT not required” — but the underlying criteria differ between age bands. Under 2 years, the rule checks altered mental status, loss of consciousness for 5 seconds or longer, severe mechanism of injury, non-frontal hematoma, palpable skull fracture, abnormal behaviour per parent, and vomiting (two or more episodes, or persistent for three hours or more).
For children aged 2 years and older, the rule checks altered mental status, any loss of consciousness, vomiting, severe mechanism of injury, signs of basilar skull fracture, severe headache, and behaviour change as reported by the parent. When every applicable criterion is negative, the residual risk of clinically important TBI is below 0.05% in both age bands — a level at which CT is not the default. When any criterion is positive, the decision shifts to CT versus observation, ideally with shared decision-making with the family.
Outcome by PECARN rule status. The rule applies once the child’s age is set; the criteria shown in the calculator swap automatically. Numbers below are population-level guidance, not a recommendation.
None present (very low risk)
Risk of clinically-important traumatic brain injury is below 0.05% in both age bands. CT is not required — observation is the appropriate next step for the under-2 and the 2+ groups alike.
Any high-risk factor present
Risk of clinically-important TBI is high enough that CT vs observation is a real decision. Discuss with the family, weigh shared decision-making, and per your institution’s pediatric head-injury pathway.
Open the calculator
Pick the child’s age band, then tick the criteria that apply. The decision — CT versus observation — updates live as you check each box, and you can copy or print a clean clinical summary for the chart.
Informational only. Not a substitute for clinical judgement. Not a patient record — PECARN results are not persisted; a refresh clears the result. PECARN applies only to children with minor head trauma (GCS 14–15) within 24 hours of injury; do not apply to moderate or severe TBI, anticoagulated children, or penetrating trauma. Always follow your institution’s pediatric head-injury pathway.