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PECARN Pediatric Head CT Rule

June 26, 2018
Sam Ashoo
The PECARN head injury rule was derived in a population of patients younger than 18 years old with blunt head injury. 42412 patients were included in the study population with a goal of identifying patients at very low risk of clinically important traumatic brain injury (ciTBI) by history and exam criteria, obviating the need for CT imaging. 

Child <2 yo

High risk criteria: CT recommended if any single criterion present. 4.4% risk ciTBI
  • GCS = 14 (Peds GCS)
  • Altered mental status
  • Palpable skull fracture
Low risk criteria: Observation vs CT recommended if any single criterion present. 0.9% risk ciTBI
  • Non-frontal hematoma
  • Not acting normally per parent
  • Severe mechanism
    • Fall >3 ft
    • MVC with ejection, death of passenger, or rollover
    • Unhelemeted pedestrian or bicyclist struck by vehicle
    • Head struck by high impact object
Avoid CT if no criteria present. <0.02% risk ciTBI

Child >2 yo

High risk criteria: CT recommended if any single criterion present 4.3% risk ciTBI
  • GCS = 14 (GCS)
  • AMS
  • Signs of basilar skull fracture
Low risk criteria: Observation vs CT recommended if any single criterion present 0.9% risk ciTBI
  • History of LOC
  • History of vomiting
  • Severe headache
  • Severe mechanism
    • Fall >5 ft
    • MVC with ejection, death of passenger, or rollover
    • Unhelemeted pedestrian or bicyclist struck by vehicle
    • Head struck by high impact object
Avoid CT if no criteria present. <0.05% risk ciTBI
 
Results: 
96.8% sensitivity > 2yo
100%  sensitivity < 2yo

Definitions and caveats:

  • The rule is unidirectional. If a child meets none of the criteria, a head CT can be safely avoided. However, if a child meets one or more criteria, that does not automatically mandate a heart CT. There are low and high risk criteria that can help with this decision:
  • Children with GCS <14 were excluded because the risk of TBI in CT is 20% and outweighs any risk of radiation exposure.
  • Overall prevalence of TBI was 5.2% 1
  • Overall prevalence of ciTBI was 0.9% 1
  • “Estimated lifetime cancer mortality risks attributable to the radiation exposure from a CT in a 1-year-old are 0.18% (abdominal) and 0.07% (head)-an order of magnitude higher than for adults-although those figures still represent a small increase in cancer mortality over the natrual background rate.” 2
MD Calc link

References: 

  1. Kuppermann N, Holmes JF, Dayan PS, et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet. 2009;374(9696):1160-70. PDF
  2. Brenner D, Elliston C, Hall E, Berdon W. Estimated risks of radiation-induced fatal cancer from pediatric CT. AJR Am J Roentgenol. 2001;176(2):289-96. PubMed
  3. PECARN Pediatric Head Trauma: Official Visual Decision Aid for Clinicians PDF
  4. Pediatric Emergency Care Applied Research Network – PECARN

 

 

 

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