PECARN: Age Matters More Than You Think
The PECARN rules split at age 2. Both assume blunt head trauma and GCS 14-15. Kids with GCS <14? They're going for CT, period. No algorithm needed.
For children <2 years:
These children can't report symptoms, so physical findings and mechanism drive the decision. High-risk features warranting CT include:
- GCS <15 or altered mental status (AMS)
- Palpable skull fracture
If neither of those is present, intermediate-risk features include: non-frontal scalp hematoma, loss of consciousness ≥5 seconds, severe mechanism (MVC with ejection, fall >3 feet, struck by high-impact object), and not acting normally per parent. Children with intermediate-risk features may be observed or imaged based on clinical judgment. Children with no high-risk or intermediate-risk features have <0.02% risk of clinically important TBI and can be safely discharged.
For children ≥2 years:
High-risk features warranting CT include:
- GCS <15 or altered mental status
- Signs of basilar skull fracture
If neither is present, intermediate-risk features include: loss of consciousness, vomiting, severe headache, severe mechanism (MVC with ejection, fall >5 feet, struck by high-impact object). Children with intermediate features may be observed or imaged based on physician experience and parental preference. Children with none of these features have very low risk of clinically important TBI.
The Three Buckets
High-risk: These kids are getting CT. They have findings strongly linked to bleeding or trauma that might need intervention (epidural, acute subdural, contusions). No debate.
Observation: These are the clinically ambiguous cases. A child with a lower-risk mechanism, moderate headache, possible single episode of vomiting, but otherwise normal examination may be appropriate for observation if parents are reliable. Serial neurologic exams performed every 15-30 minutes over 4-6 hours allow detection of deterioration manifested by mental status change, pupil abnormalities, recurrent vomiting, or behavioral changes. Any concerning findings warrant imaging.
Low-risk: No high-risk features, no observation red flags, normal exam. These kids go home. Assuming your parents are reliable and understand what to look for.
Use PECARN Calculator to systematically apply decision rule and document risk stratification.
GCS in Young Kids: It's Different
The Glasgow Coma Scale was developed for adults. A frightened or fatigued young child may not follow commands, which does not indicate brain injury. This distinction is critical in pediatric assessment.
For children less than 5 years old, the verbal component should be modified:
- Crying or fussy behavior corresponds to "inappropriate words"
- Inconsolable behavior corresponds to "confused speech"
- Vocalizations or response to voice corresponds to "oriented speech"
Motor and eye opening stay standard.
GCS less than 15 mandates imaging. A GCS of 14 might be considered for observation if all other examination findings are reassuring and pupil responses are normal; however, in most cases, imaging is performed to exclude intracranial injury. Serial neurologic assessment in young children is challenging and prone to misinterpretation.
Use Glasgow Coma Scale calculator for standardized documentation and communication.
When to Image, When to Observe, When to Send Home
Get CT:
- Any high-risk feature
- Hematoma/contusion in kids <2
- Suspected abuse
- New focal deficits during observation
Observation is okay:
- Low-risk exam, reliable parents, good follow-up plan
- Use structured serial exams (15-30 min for the first couple hours, then stretch to 30-60 min)
Discharge without CT:
- No high-risk features, normal neuro exam, solid parents
- That's it. Reassurance and clear return precautions.
During observation, monitor for mental status changes, pupil abnormalities, new motor deficits, escalating headache or vomiting, and behavioral changes. Any of these findings warrant immediate CT imaging. The majority of clinically significant intracranial injuries become apparent within the first 4-6 hours.
Document your risk category and exam clearly so the next person knows what you found and what you're watching for.
Use Pediatric Trauma Score to assess overall trauma severity and guide ICU versus floor admission.
Summary
The PECARN decision rules are evidence-based tools that enable confident deferral of imaging in appropriate patients while reducing unnecessary radiation exposure. Successful application requires accurate risk stratification, careful serial neurologic examination, ensuring parental understanding of warning signs, age-appropriate interpretation of GCS, meticulous documentation, and reliable follow-up mechanisms.