PECARN
Assess pediatric head trauma risk using the validated PECARN clinical decision rule. Select age group, check clinical findings, and get CT imaging recommendations with risk percentages.
GCS ≤ 14, altered mental status, or signs of skull fracture
Additional predictors associated with ~0.9% risk of ciTBI each
About This Calculator
The PECARN Pediatric Head Injury Risk Calculator helps emergency clinicians assess the risk of clinically important traumatic brain injury (ciTBI) in children presenting with blunt head trauma and Glasgow Coma Scale (GCS) scores of 14–15. Developed by the Pediatric Emergency Care Applied Research Network and validated in a landmark prospective cohort study of over 42,000 children (Kuppermann et al., The Lancet, 2009), this clinical decision rule helps determine when CT imaging is necessary while avoiding unnecessary radiation exposure.
The calculator uses a two-tiered risk stratification system. Category A (high-risk indicators) includes GCS ≤ 14, altered mental status, and signs of skull fracture — any one present indicates approximately 4.3% risk of ciTBI, and CT imaging is recommended. Category B (intermediate-risk predictors) includes scalp hematoma, loss of consciousness, vomiting, severe headache, severe mechanism of injury, or not acting normally per parent — each predictor adds approximately 0.9% risk, and the decision for CT vs observation depends on clinical judgment. When no predictors are present, the risk is extremely low (<0.02–0.05%), and CT is not indicated.
Why PECARN Matters
Pediatric head trauma is a common emergency department presentation, but ciTBI is rare (approximately 0.9% of cases). CT scans expose children to significant radiation — one head CT equals about 200 chest X-rays, and studies show childhood CT exposure increases lifetime cancer risk by up to 47%. The PECARN rule was specifically developed to identify the vast majority of children who do not need imaging, reducing unnecessary radiation while maintaining excellent sensitivity for clinically significant injuries.
Regional Application
United States: The PECARN rule was developed by a US-based network and is widely implemented in American emergency departments. It is endorsed by the American Academy of Pediatrics for minor head trauma evaluation.
United Kingdom: NICE guidelines for head injury (CG176) incorporate PECARN-derived principles for pediatric assessment, though specific referral pathways may use CHALICE or NICE criteria. The rule complements clinical judgment in UK emergency settings.
India: While PECARN was validated in North American EDs, its principles are applicable globally. Indian emergency physicians increasingly use PECARN alongside local protocols. The risk of radiation from unnecessary CTs is equally relevant in Indian practice.
Frequently Asked Questions
What does PECARN stand for?
PECARN stands for the Pediatric Emergency Care Applied Research Network, a US federally-funded multi-institutional research network that developed validated clinical decision rules for pediatric head trauma to determine when CT imaging is necessary.
How does the PECARN pediatric head injury calculator work?
Select the patient's age group (under 2 years or 2 years and older), then check all applicable clinical findings from two categories. Category A includes high-risk indicators (GCS ≤ 14, altered mental status, signs of skull fracture) where any one present suggests ~4.3% risk of ciTBI and CT is recommended. Category B includes intermediate-risk predictors (scalp hematoma, LOC, vomiting, severe mechanism, severe headache, not acting normally) where each adds ~0.9% risk and CT vs observation is considered.
When should I use the PECARN rule?
The PECARN rule should be used in children with blunt head trauma presenting with Glasgow Coma Scale (GCS) scores of 14 or 15. It is designed for emergency department settings to help clinicians decide whether CT imaging is needed to rule out clinically important traumatic brain injury.
What is the risk of ciTBI in the low-risk PECARN category?
In the very low-risk category (no predictors present), the risk of clinically important traumatic brain injury is less than 0.02% for children under 2 years and less than 0.05% for children aged 2 years and older. CT imaging is not indicated in these patients.
What are the high-risk PECARN criteria for children under 2 years?
For children under 2 years, the high-risk PECARN criteria are: Glasgow Coma Scale (GCS) score of 14 or less, altered mental status (agitation, somnolence, slow response, repetitive questioning), or palpable skull fracture. Any one of these findings indicates a ~4.3% risk of ciTBI and CT is recommended.
What are the high-risk PECARN criteria for children 2 years and older?
For children 2 years and older, the high-risk PECARN criteria are: Glasgow Coma Scale (GCS) score of 14 or less, altered mental status, or signs of basilar skull fracture (Battle sign, raccoon eyes, CSF otorrhea or rhinorrhea). Any one of these findings indicates a ~4.3% risk of ciTBI and CT is recommended.
Can this PECARN calculator replace clinical judgment?
No, this calculator is a clinical decision support tool and cannot replace professional medical judgment. The PECARN rule should be used in conjunction with thorough clinical assessment, and decisions about CT imaging should consider multiple factors including clinical experience, number of findings, symptom progression, patient age, and parental preference.
What is the risk of cancer from pediatric CT scans?
A major Dutch study published in the Journal of the National Cancer Institute found that exposure to CT scans in early childhood increases the risk of developing cancer by up to 47%. One CT scan is equivalent to approximately 200 chest X-rays. This underscores why the PECARN rule is valuable for avoiding unnecessary radiation exposure in children.