What are the PECARN (Pediatric Emergency Care Applied Research Network) criteria for determining the need for a computed tomography (CT) scan in children with minor head trauma?

PECARN Criteria for CT Imaging in Pediatric Head Trauma

The PECARN criteria stratify children with minor head trauma into three risk categories based on age-specific clinical features, with very low-risk children safely avoiding CT, intermediate-risk children managed by observation versus selective CT, and high-risk children requiring immediate CT imaging. 1, 2

Risk Stratification by Age Group

Children ≥2 Years of Age

Very Low Risk (CT NOT indicated):

• GCS = 15 with normal mental status
• No signs of basilar skull fracture
• No history of loss of consciousness
• No vomiting
• No severe mechanism of injury
• No severe headache
• Risk of clinically important TBI: <0.02% 1, 2

Intermediate Risk (CT may be considered vs. observation):

• GCS = 15 with normal mental status
• No basilar skull fracture signs
• BUT one or more of: loss of consciousness, vomiting, severe mechanism of injury, or severe headache
• Risk of clinically important TBI: ~0.8% 1

High Risk (CT strongly recommended):

• GCS = 14 or other signs of altered mental status, OR
• Signs of basilar skull fracture
• Risk of clinically important TBI: ~4.3% 1, 2

Children <2 Years of Age

Very Low Risk (CT NOT indicated):

• GCS = 15 with normal mental status
• No palpable skull fracture
• No nonfrontal scalp hematoma
• Loss of consciousness ≤5 seconds
• No severe mechanism of injury
• Acting normally per parents
• Risk of clinically important TBI: <0.02% with 100% sensitivity and 100% NPV validated in >4,000 children 1

Intermediate Risk (CT may be considered vs. observation):

• GCS = 15 with normal mental status
• No palpable skull fracture
• BUT one or more of: loss of consciousness >5 seconds, severe mechanism of injury, or not acting normally per parent
• Risk of clinically important TBI: ~0.9% 1

High Risk (CT strongly recommended):

• GCS = 14 or other signs of altered mental status, OR
• Any palpable skull fracture
• Risk of clinically important TBI: ~4.4% 1, 2

Clinical Decision Algorithm

For Very Low-Risk Patients:

• Safely discharge without CT imaging 1, 2
• Provide written discharge instructions including warning signs: persistent vomiting, increasing drowsiness, seizures, worsening headache, behavioral changes, unsteady gait, unequal pupils 3, 4

For Intermediate-Risk Patients:

• Consider clinical observation as preferred strategy over immediate CT 1
• CT may be obtained instead of observation when: parental preference for imaging, multiple risk factors present, worsening symptoms during observation, or young infants where observational assessment is challenging 1
• Planned observation reduces CT utilization by 80% without missing clinically important injuries 5

For High-Risk Patients:

• Obtain immediate non-contrast head CT 1, 2
• CT provides rapid acquisition, excellent sensitivity for acute hemorrhage and fractures, and requires no sedation 2, 3

Important Clinical Considerations

Special Population - Infants <3 Months:

• Maintain lower threshold for neuroimaging as these infants have increased risk of significant injury with subtle findings 4, 6
• Even low-risk infants <3 months remain at 5.1% risk for TBI on CT and 4.6% risk for skull fractures, despite only 0.2% risk of clinically important TBI 6

Imaging Modality Selection:

• CT is the first-line modality due to rapid acquisition, no sedation requirement, and excellent sensitivity for acute hemorrhage 2, 3
• Skull radiographs are inadequate as they miss up to 50% of intracranial injuries 1
• MRI is more sensitive but impractical acutely due to length of examination and frequent need for sedation in young children 1

Common Pitfalls to Avoid:

• Do not obtain CT in very low-risk patients meeting all PECARN criteria - this exposes them to unnecessary radiation with <0.02% risk of injury 1, 2
• Do not rely on skull radiographs - they have only 63% sensitivity for fractures and cannot detect intracranial injuries 4
• Consider non-accidental trauma in infants <1 year with unexplained injuries, inconsistent history, or multiple fractures 3, 4
• Weekend presentation, older age, and any loss of consciousness are associated with higher CT utilization rates in intermediate-risk patients 7