Pecarn Head Injury Calculator

Q: What is the PECARN pediatric head injury prediction rule?

The PECARN (Pediatric Emergency Care Applied Research Network) head injury prediction rule is an evidence-based clinical decision tool designed to identify children at very low risk of clinically important traumatic brain injury (ciTBI) after minor head trauma. Published by Kuppermann et al. in 2009 in The Lancet, it was developed from a large prospective cohort study of over 42,000 children acros

Q: Why are there separate PECARN criteria for children under 2 versus 2 and older?

Separate criteria exist because head injury presentation and risk factors differ significantly between these age groups. Children under 2 years are more difficult to assess clinically because they cannot articulate symptoms like headache. Their skulls are thinner and more pliable, making palpable skull fracture a meaningful finding. Non-occipital scalp hematomas are less concerning in older childr

Q: What is a clinically important traumatic brain injury as defined by PECARN?

PECARN defines clinically important traumatic brain injury (ciTBI) as any of the following outcomes: death from TBI, neurosurgical intervention for TBI (intracranial pressure monitoring, elevation of depressed skull fracture, ventriculostomy, hematoma evacuation, lobectomy, tissue debridement, or dural repair), intubation for more than 24 hours for TBI, or hospital admission for 2 or more nights f

Q: How does the PECARN rule reduce unnecessary CT scans in children?

The PECARN rule reduces unnecessary CT scans by providing a validated method to identify the approximately 95 percent of children with minor head trauma who are at very low risk for ciTBI. Before PECARN, CT utilization rates for pediatric head trauma varied widely between institutions, ranging from 15 to 53 percent. Implementation of the PECARN rule has been shown to reduce CT rates by 20 to 30 pe

Q: What should clinicians do with intermediate-risk patients on the PECARN algorithm?

Intermediate-risk patients present the most challenging clinical decision point in the PECARN algorithm. These children have approximately 0.8 to 0.9 percent risk of ciTBI, which is low but not negligible. The PECARN rule recommends that the decision to obtain CT versus observe should be based on several factors: physician experience and clinical gestalt, whether symptoms are worsening or improvin

Q: How reliable is parental assessment that a child is not acting normally after head injury?

Parental or caregiver assessment is a uniquely important criterion in the PECARN rule for children under 2, reflecting the clinical reality that parents often detect subtle behavioral changes that clinicians may miss during a brief emergency department evaluation. Studies validating the PECARN rule found that when parents reported their child was not acting normally, the risk of ciTBI was signific

Determine need for CT scan in pediatric minor head trauma using PECARN criteria. Enter values for instant results with step-by-step formulas.

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Formula

PECARN Algorithm: Age-specific criteria stratify into High Risk, Intermediate Risk, or Low Risk for ciTBI

Separate algorithms for children under 2 and 2+ years. High-risk criteria indicate CT recommendation. Intermediate-risk criteria suggest observation vs CT. Absence of all criteria indicates very low risk where CT is not recommended.

Worked Examples

Example 1: 18-Month-Old with Intermediate Risk

Problem: An 18-month-old fell from a 4-foot high changing table, has a large occipital scalp hematoma, but GCS is 15, no altered mental status, no palpable skull fracture, no loss of consciousness, and parents say the child is acting normally.

Solution: Age group: Under 2 years\nHigh-risk criteria: GCS < 15 (No), Altered mental status (No), Palpable skull fracture (No)\nIntermediate-risk criteria:\n- Scalp hematoma (occipital): YES\n- LOC >= 5 seconds: No\n- Severe mechanism (fall > 3 ft): YES\n- Not acting normally: No\nTwo intermediate criteria present = Intermediate Risk\nciTBI risk: ~0.9%

Result: PECARN: Intermediate Risk (ciTBI ~0.9%) - Observation vs CT based on clinical judgment. Consider CT given two intermediate criteria present.

Example 2: 5-Year-Old with Low Risk

Problem: A 5-year-old fell off a bicycle (no motor vehicle involvement) from standing height, briefly cried, has a small frontal bump, GCS 15, no altered mental status, no signs of basilar skull fracture, no LOC, no vomiting, no headache.

Solution: Age group: 2 years and older\nHigh-risk criteria: GCS < 15 (No), Altered mental status (No), Basilar skull fracture signs (No)\nIntermediate-risk criteria:\n- LOC: No\n- Vomiting: No\n- Severe mechanism: No (fall from standing, no MVC)\n- Severe headache: No\nNo high or intermediate criteria = Low Risk\nciTBI risk: < 0.05%

Result: PECARN: Low Risk (ciTBI < 0.05%) - CT NOT recommended. Discharge with head injury precautions.

Frequently Asked Questions

What is the PECARN pediatric head injury prediction rule?

The PECARN (Pediatric Emergency Care Applied Research Network) head injury prediction rule is an evidence-based clinical decision tool designed to identify children at very low risk of clinically important traumatic brain injury (ciTBI) after minor head trauma. Published by Kuppermann et al. in 2009 in The Lancet, it was developed from a large prospective cohort study of over 42,000 children across 25 emergency departments. The rule uses separate algorithms for children under 2 years and children 2 years and older, stratifying patients into high-risk, intermediate-risk, and low-risk categories. Its primary purpose is to safely reduce unnecessary CT scans while identifying children who need imaging.

Why are there separate PECARN criteria for children under 2 versus 2 and older?

Separate criteria exist because head injury presentation and risk factors differ significantly between these age groups. Children under 2 years are more difficult to assess clinically because they cannot articulate symptoms like headache. Their skulls are thinner and more pliable, making palpable skull fracture a meaningful finding. Non-occipital scalp hematomas are less concerning in older children but significant in infants. Conversely, children 2 and older can report headache and other symptoms. Signs of basilar skull fracture replace palpable skull fracture as a high-risk criterion in the older group. The fall height threshold also differs: greater than 3 feet for children under 2 versus greater than 5 feet for older children.

What is a clinically important traumatic brain injury as defined by PECARN?

PECARN defines clinically important traumatic brain injury (ciTBI) as any of the following outcomes: death from TBI, neurosurgical intervention for TBI (intracranial pressure monitoring, elevation of depressed skull fracture, ventriculostomy, hematoma evacuation, lobectomy, tissue debridement, or dural repair), intubation for more than 24 hours for TBI, or hospital admission for 2 or more nights for TBI with findings on CT. This definition deliberately excludes isolated non-depressed skull fractures and brief hospital admissions for observation alone, as these are not considered clinically important outcomes. The ciTBI definition ensures the rule focuses on injuries that truly require intervention rather than incidental CT findings.

How does the PECARN rule reduce unnecessary CT scans in children?

The PECARN rule reduces unnecessary CT scans by providing a validated method to identify the approximately 95 percent of children with minor head trauma who are at very low risk for ciTBI. Before PECARN, CT utilization rates for pediatric head trauma varied widely between institutions, ranging from 15 to 53 percent. Implementation of the PECARN rule has been shown to reduce CT rates by 20 to 30 percent without missing clinically important injuries. This is particularly important because CT scanning exposes children to ionizing radiation, which carries a small but real increased lifetime cancer risk, estimated at approximately 1 in 5,000 for a head CT in a young child. The negative predictive value of the PECARN rule exceeds 99.9 percent for the low-risk group.

What should clinicians do with intermediate-risk patients on the PECARN algorithm?

Intermediate-risk patients present the most challenging clinical decision point in the PECARN algorithm. These children have approximately 0.8 to 0.9 percent risk of ciTBI, which is low but not negligible. The PECARN rule recommends that the decision to obtain CT versus observe should be based on several factors: physician experience and clinical gestalt, whether symptoms are worsening or improving, the number of intermediate-risk criteria present (more criteria increases concern), patient age (younger children have lower CT threshold), and parental preference. Observation for 4 to 6 hours with serial neurological examinations is a reasonable alternative to immediate CT, with imaging obtained if symptoms worsen or fail to improve.

How reliable is parental assessment that a child is not acting normally after head injury?

Parental or caregiver assessment is a uniquely important criterion in the PECARN rule for children under 2, reflecting the clinical reality that parents often detect subtle behavioral changes that clinicians may miss during a brief emergency department evaluation. Studies validating the PECARN rule found that when parents reported their child was not acting normally, the risk of ciTBI was significantly elevated even when other criteria were absent. This criterion captures a broad range of concerning behaviors including unusual irritability, excessive sleepiness, decreased feeding, and changes in interaction patterns. While subjective, parental concern has been validated as a meaningful predictor and should be taken seriously in clinical decision-making.