What are the Pediatric Emergency Care Applied Research Network (PECARN) criteria for deciding when to obtain an emergent computed tomography (CT) scan of the head in children with head trauma, stratified by age (< 2 years and ≥ 2 years)?

Head CT Protocol for Pediatric Head Injury

Apply the PECARN Decision Rule to Stratify Risk by Age

The American College of Radiology and American Academy of Pediatrics recommend using the validated PECARN clinical decision rule to determine which children require head CT after trauma, stratified by age < 2 years versus ≥ 2 years. 1, 2

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For Children < 2 Years Old

High-Risk Features → Immediate CT Required

Obtain urgent non-contrast head CT if any of the following are present (risk of clinically important traumatic brain injury ≈ 4.3–4.4%): 1, 2, 3

• Glasgow Coma Scale (GCS) ≤ 14 or altered mental status 1, 3
• Palpable skull fracture 1, 3
• Post-traumatic seizure 1
• Focal neurological deficit 1

Intermediate-Risk Features → Consider CT or Observation

For infants with GCS 15 and normal mental status but any of the following (risk ≈ 0.9%): 1, 2, 3

• Loss of consciousness > 5 seconds 1, 2
• Severe mechanism of injury (e.g., motor vehicle collision with ejection, fall > 3 feet, struck by high-impact object) 1, 2
• Non-frontal scalp hematoma (occipital, parietal, or temporal) 1, 2
• Not acting normally per parent report 1, 2

Clinical strategy: Extended emergency department observation (4–6 hours with hourly neurologic reassessment) reduces CT utilization without missing clinically important injuries; proceed to CT if symptoms persist, worsen, or new findings emerge. 1

Very Low-Risk → No CT Needed

Children can safely avoid CT when all of the following are present (risk < 0.02%, sensitivity 100%, negative predictive value 100%): 1, 2, 3

• GCS 15 1, 2
• Normal mental status 1, 2
• No palpable skull fracture 1, 2
• No non-frontal scalp hematoma 1, 2
• Loss of consciousness ≤ 5 seconds 1, 2
• No severe mechanism of injury 1, 2
• Acting normally per parent 1, 2

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For Children ≥ 2 Years Old

High-Risk Features → Immediate CT Required

Obtain urgent non-contrast head CT if any of the following are present (risk ≈ 4.3%): 1, 2

• GCS ≤ 14 or altered mental status 1, 2
• Signs of basilar skull fracture (hemotympanum, Battle sign, raccoon eyes, cerebrospinal fluid otorrhea/rhinorrhea) 1, 2
• Post-traumatic seizure 1
• Focal neurological deficit (including transient visual disturbance) 1

Intermediate-Risk Features → Consider CT or Observation

For children with GCS 15 and normal mental status but any of the following (risk ≈ 0.8%): 1, 2

• History of loss of consciousness 1, 2
• Vomiting (especially if persistent or multiple episodes) 1, 2
• Severe headache 1, 2
• Severe mechanism of injury 1, 2

Clinical strategy: CT may be favored when multiple intermediate-risk factors coexist, symptoms worsen during observation, or vomiting persists; otherwise, 4–6 hours of observation with hourly reassessment is safe and reduces unnecessary imaging. 1

Very Low-Risk → No CT Needed

Children can safely avoid CT when all of the following are present (risk < 0.05%, sensitivity > 96%, negative predictive value 99.9%): 1, 2

• GCS 15 1, 2
• Normal mental status 1, 2
• No signs of basilar skull fracture 1, 2
• No loss of consciousness 1, 2
• No vomiting 1, 2
• No severe mechanism of injury 1, 2
• No severe headache 1, 2

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CT Imaging Protocol When Indicated

• Perform non-contrast head CT using pediatric-specific, size-adjusted protocols following the ALARA principle ("as low as reasonably achievable") to minimize radiation exposure. 1, 2
• Acquire multiplanar and 3D reconstructions to increase sensitivity for small fractures and hemorrhages. 1, 2
• Do not use intravenous contrast initially, as it may obscure subtle hemorrhages. 1

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Critical Pitfalls to Avoid

• Do not rely on skull radiographs to exclude intracranial injury; they miss up to 50% of intracranial injuries and provide no information about brain parenchyma. 1, 3
• Do not use ultrasound (even with open fontanelle) to exclude intracranial injury in infants, as it lacks sensitivity for subdural hematomas, posterior fossa injuries, and other small hemorrhages. 3
• Do not delay CT when high-risk features are present; immediate imaging is critical for timely neurosurgical intervention. 1
• Do not obtain CT in very low-risk patients who meet all PECARN criteria for safe discharge; this exposes them to unnecessary radiation (lifetime cancer risk) without clinical benefit. 1
• Suspect non-accidental trauma in children < 2 years with inconsistent history or unexplained injuries; obtain CT or MRI regardless of clinical presentation. 1, 2

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Discharge Instructions for Observed or Very Low-Risk Patients

Instruct parents to return immediately if the child develops: 1

• Persistent or worsening vomiting 1
• Excessive somnolence or difficulty arousing 1
• New seizures 1
• Worsening headache 1
• Unsteady gait 1
• Unequal pupil size 1

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Balancing Radiation Risk Against Injury Risk

• Head CT exposes children to ionizing radiation that increases lifetime risk of brain tumors and leukemia; children are especially vulnerable due to rapidly dividing cells and decades for cancer development. 1
• However, in high-risk patients, the immediate 4.3% risk of clinically important traumatic brain injury requiring urgent intervention far outweighs the minute lifetime cancer risk from a single CT scan. 1
• Validated clinical decision rules (PECARN) allow safe identification of very low-risk children who can avoid CT entirely, minimizing unnecessary radiation exposure. 1, 2
• Discuss both the immediate injury risk and long-term radiation risk with families to support informed decision-making. 1