What is the indication for a computed tomography (CT) head scan to rule out significant intracranial injury in pediatric patients with suspected head injury, considering the site of impact and clinical presentation?

CT Head Indications in Pediatric Head Trauma

Use the validated PECARN criteria to stratify pediatric head trauma patients by age and risk factors, obtaining CT head without contrast for high-risk patients, considering CT versus observation for intermediate-risk patients, and safely avoiding CT in very low-risk patients. 1, 2

Risk Stratification Framework by Age

Children ≥2 Years of Age

High-Risk Criteria (CT Strongly Recommended):

• GCS of 14 or other signs of altered mental status 1, 2
• Signs of basilar skull fracture 1, 2
• Risk of clinically important traumatic brain injury: approximately 4.3% 1

Intermediate-Risk Criteria (CT May Be Considered vs. Observation):

• GCS of 15 with normal mental status AND no basilar skull fracture, but with:
  • History of loss of consciousness 2
  • Vomiting 2
  • Severe mechanism of injury 1
  • Severe headache 1, 2
• Risk of clinically important injury: approximately 0.8% 1

Very Low-Risk Criteria (CT Not Indicated):

• GCS of 15 1, 2
• Normal mental status 1, 2
• No basilar skull fracture 2
• No vomiting 2
• No severe mechanism of injury 2
• No severe headache 2
• Risk of clinically important traumatic brain injury: <0.02% 1

Children <2 Years of Age

High-Risk Criteria (CT Strongly Recommended):

• GCS of 14 or other signs of altered mental status 1, 3
• Palpable skull fracture 1, 3
• Risk of clinically important intracranial injury: approximately 4.4% 3

Intermediate-Risk Criteria (CT May Be Considered vs. Observation):

• GCS of 15 with normal mental status AND no palpable skull fracture, but with:
  • Loss of consciousness >5 seconds 1
  • Severe mechanism of injury 1
  • Not acting normally per parent 1
• Risk of significant injury: approximately 0.9% 1, 3

Very Low-Risk Criteria (CT Not Indicated):

• GCS of 15 1
• Normal mental status 1
• No palpable skull fracture 1
• No nonfrontal scalp hematoma 1
• Loss of consciousness ≤5 seconds 1
• No severe mechanism of injury 1
• Acting normally per parents 1
• Validated sensitivity: 100%, negative predictive value: 100% in over 4,000 children 1

Site of Impact Considerations

Scalp Hematoma Location (Children <2 Years):

• Nonfrontal scalp hematoma is a risk factor requiring consideration for CT 1
• Frontal scalp hematomas carry lower risk and do not automatically require imaging in otherwise low-risk patients 1

Skull Fracture Detection:

• Palpable skull fracture in children <2 years is a high-risk criterion 1, 3
• Signs of basilar skull fracture in children ≥2 years is a high-risk criterion 1, 2
• Up to 50% of intracranial injuries occur without skull fracture 1, 3
• Skull radiographs are insufficient and should not be used, as they miss up to 50% of intracranial injuries 1, 2

Clinical Decision-Making Algorithm

For Intermediate-Risk Patients:

• CT may be considered in lieu of observation when: 1
  • Parental preference for definitive imaging
  • Multiple risk factors present
  • Worsening clinical symptoms or signs during observation
  • Young infants where observational assessment is challenging

Observation Strategy:

• Every additional hour of emergency department observation is associated with decreased CT utilization without delay in diagnosis of significant traumatic brain injury 2
• Clinical deterioration during observation warrants immediate CT imaging 2

Imaging Technical Specifications

CT Protocol:

• Non-contrast CT head is the modality of choice 2, 4
• Use dedicated pediatric-specific, reduced-dose protocols following ALARA principle 2
• Multiplanar and 3D-reconstructed images increase sensitivity for fractures and small hemorrhages 2
• Rapid acquisition time with excellent sensitivity for acute intracranial hemorrhage and fractures 2, 4
• No sedation required, unlike MRI 2

Alternative Imaging (Not Recommended Acutely):

• MRI is impractical in acute setting due to longer examination times, safety screening requirements, and frequent need for sedation in younger children 1
• Skull radiographs miss up to 50% of intracranial injuries and provide no information about brain parenchyma 1, 2
• Ultrasound lacks sensitivity for small subdural hematomas, particularly in posterior fossa, even when fontanelle is open 3

Critical Pitfalls to Avoid

Do Not:

• Obtain CT in very low-risk patients meeting all PECARN criteria, as this exposes them to unnecessary radiation 2
• Rely on presence or absence of skull fracture alone to predict intracranial injury 1, 3
• Use skull radiographs as they are insufficient for evaluation of traumatic brain injury 1, 2
• Apply PECARN criteria to suspected abusive head trauma cases; these children require either CT or MRI regardless of clinical presentation 2
• Delay imaging when high-risk features are present 2
• Assume normal neurologic exam excludes significant intracranial injury, as 16% of children with GCS 15 and no loss of consciousness may have intracranial injury 5

Special Considerations:

• Post-traumatic seizures are a high-risk criterion requiring immediate CT imaging 2
• Loss of consciousness alone is not a sensitive indicator for selecting patients for CT scanning 5
• Vomiting and headache must be "severe" to qualify as intermediate-risk factors; mild symptoms do not automatically warrant CT 2