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    PECARN Pediatric Head Injury/Trauma Algorithm

    Predicts need for brain imaging after pediatric head injury.


    Note: This only applies to children with GCS scores of 14 or greater.
    When to Use
    Why Use

    The PECARN Pediatric Head Injury Prediction Rule is a well-validated clinical decision aid that allows physicians to safely rule out the presence of clinically important traumatic brain injuries, including those that would require neurosurgical intervention among pediatric head injury patients who meet its criteria without the need for CT imaging.

    • The PECARN consortium produced the largest study to date aiming to derive and validate clinical prediction rules to identify children with very low risk of Clinically Important TBI (ciTBI) following blunt head trauma who would not require imaging.
    • ciTBI (see “More Info” section for outcome definitions) was chosen as the primary outcome because it is clinically-driven and accounts for the imperfect test characteristics of CT.
    • In the less than 2 year old group, the rule was 100% sensitive.
    • In the greater than 2 year old group, the rule had 96.8% sensitivity.
    • In those under 2 with GCS=14, AMS, or palpable skull fracture, risk was 4.4% and CT imaging is recommended.
      • Risk with any of the remaining predictors was 0.9%, and less than 0.02% with no predictors.
    • In those over 2 with GCS=14, AMS, or signs of basilar skull fracture, risk was 4.3% and CT imaging is recommended.
      • Risk with any of the remaining 4 predictors was 0.9%, and less than 0.05% with no predictors.
    • PECARN prediction rule outperformed both the CHALICE and the CATCH clinical decision aids in external validation studies.

    Points to keep in mind:

    • Although the largest trial of its kind, the PECARN study had low rates of TBI on Head CT (5.2%) and even lower rates of ciTBI (0.9%) – this suggests overall TBI in children is rare!
    • Head CTs were obtained in approximately 35% of patients, lower than the average estimate of 50%!
    • Unlike in the adult population, CT imaging of the head in pediatric patients is believed to be associated with an increased risk of lethal malignancy over the life of the patient, with the risk decreasing with age. The estimated risk of lethal malignancy from a head CT in a 1 year is 1 in 1000-1500 and decreases to 1 in 5000 in a patient who is 10 years old.
    • There are over 600,000 emergency department visits annually in the US for head trauma among patients aged 18 years or younger.
    • Applying the PECARN Pediatric Head Injury Prediction Rule would allow providers to determine which pediatric patients they can safely discharge without obtaining a head CT.


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    Next Steps
    Creator Insights


    • In patients with suspected or radiologically-confirmed TBI, first assess ABC’s and consider neurosurgical/ICU consultation or local policies in regards to fluid management, seizure prophylaxis, hypertonic saline/mannitol, disposition, etc.
    • Observation for 4-6 hours for those who are not imaged to assess for changes in clinical status.
    • Reassurance, Education, and Strict Return Precautions for those discharged without imaging.
    • Follow-up with primary care provider or neurologist and Return to Play/School anticipatory guidance if concussion is suspected.


    PECARN Algorithm:

    PECARN algorithm

    Critical Actions

    • ciTBI was a rare event (0.9%) and neurosurgical intervention was even more rare (0.1%).
    • Over 50% of each age cohort did not meet any predictors, and CT imaging is not indicated for the vast majority of these patients as risk of ciTBI was exceedingly low.
    • Risk of ciTBI was >4% with either of the 2 higher-risk predictors in each age cohort, and imaging is recommended.
    • For the remaining 4 lower-risk predictors in each cohort the risk of ciTBI is approximately 0.9% per predictor, and CT imaging versus observation is indicated.
      • Judgment may be based on clinical experience, single versus multiple findings, signs clinical deterioration during observation period, patient age, and parental preference.


    Prediction tree using a series of dichotomous Yes/No questions, as above.

    Facts & Figures

    Definition of clinically-important traumatic brain injury (ciTBI) (any of the following satisfy definition):

    • Death from traumatic brain injury (TBI)
    • Neurosurgical intervention for traumatic brain injury
      • Intracranial pressure monitoring
      • Elevation of depressed skull fracture
      • Ventriculostomy
      • Hematoma evacuation
      • Lobectomy
      • Tissue debridement
      • Dura repair
      • Other
    • Intubation of more than 24 hours for TBI
    • Hospital admission of 2 nights or more for the TBI in association with TBI on CT
      • Hospital admission for TBI defined by admission for persistent neurological symptoms or signs such as persistent alteration in mental status, recurrent emesis due to head injury, persistent severe headache or ongoing seizure management

    Definition of traumatic brain injury on CT (any of the following satisfy definition):

    • Intracranial hemorrhage or contusion
    • Cerebral edema
    • Traumatic infarction
    • Diffuse axonal injury
    • Shearing injury
    • Sigmoid sinus thrombosis
    • Midline shift of intracranial contents or signs of brain herniation
    • Diastasis of the skull
    • Pneumocephalus
    • Skull fracture depressed by at least the width of the table of the skull

    Evidence Appraisal

    • The original PECARN trial included 42,412 children < 18 years old presenting to 1 of 25 North American PECARN-affiliated emergency departments with 33,785 in derivation cohort (8,502 < 2 years old) and 8,627 in the validation cohort (2,216 <2years old).
    • CT scans were performed at the physician’s discretion in 35.3% while medical records, telephone surveys, and county morgue records were used to assess for cases of missed ciTBI in those discharged without imaging.
      • Potential for CT reduction quoted above is likely underestimated given that CT utilization in this study (35.3%) was significantly lower than the estimated average in North American EDs (50%).
    • TBI, as defined in the “More Info” header occurred in 5.2% of patients.
    • 9% of patients were admitted to the hospital.
    • ciTBI occurred in 0.9% of the cohort, neurosurgery was performed in 0.1% of the overall cohort, and zero patients died.
    • In patients <2 years of age that were negative for any PECARN risk factor, the aid was 100% sensitive (95% CI 86.3-100) with NPV of 100% (95% CI 99.7-1000) for ruling out ciTBI in the validation cohort.
    • In patient > 2 years of age that were negative for any PECARN risk factor, the aid was 96.8% sensitive (95% CI 89.0-99.6) with NPV of 99.95% (95% CI 99.8-99.99) for ruling out ciTBI in the validation cohort External validation studies have demonstrated sensitivity of 100% for ciTBI and any injury requiring neurosurgery.
      • The algorithm has reasonable specificity (53%-60%) considering its extremely high sensitivity.
        • 60 (15.9%) of 376 patients with ciTBI underwent neurosurgery, 8 (2.1%) with ciTBI were intubated >24 Hours, and 0 patients died.
        • As a result of the infrequency of ciTBI, the lower bounds of the confidence intervals of sensitivity started at 86 and 89%, respectively, for the <2 and > 2 years of age cohorts.
        • The NPV confidence intervals were very tightly approximating 100%.
    • PECARN has now been externally validated in 2 separate studies.
      • One trial of 2439 children in 2 North American and Italian centers found PECARN to be 100% sensitive for ruling out ciTBI in both age cohorts.
      • The rates of ciTBI at 0.8% (19/2439) and those requiring neurosurgery 0.08% (2/2439) were similar to the PECARN trial.
      • A second trial at a single US emergency department of 1009 patients under 18 years of age prospectively compared PECARN to two other pediatric head CT decision aids (CHALICE and CATCH) as well as to physician estimate and physician practice.
      • 2% (21/1009) had ciTBI and neurosurgery was needed in 0.4% (4/1009) of this sample.
      • Again PECARN was found to be 100% sensitive for identifying ciTBI.
      • PECARN outperformed both the CHALICE and CATCH decision aids (91% and 84% sensitive for ciTBI, respectively).
    • Although the goal was to Rule-Out those with very low risk of ciTBI, the prediction rule also performed well to Rule-Out TBI on Head CT.
    • In those <2 years old, sensitivity and NPV were 100% for TBI on CT with narrow confidence intervals.
    • In those >2 years old, sensitivity was 98.4% and NPV 94% for TBI on CT with relatively narrow confidence intervals.
    • 2 recent PECARN subgroup analyses attempted to further risk-stratify patients with single predictors (e.g., Isolated scalp hematoma in patients <2years old).
      • ciTBI was too uncommon to apply age, hematoma size, or hematoma location predictors.
      • There were several non-statistically significant trends for higher rates or TBI on Head CT that may affect imaging tendencies (e.g., <3months of age, Non-frontal hematoma + Large size).
    • Another sub-analysis of those with isolated vomiting (i.g., no other PECARN predictors) reiterated the parent study results.
    • In the >2 year old cohort, there was a low rate of TBI on Head CT (3.2%, 26/806) and an even lower rate of ciTBI (0.7%, 10/1,501) so observation rather than emergent imaging is indicated in the majority of these patients.
    • Number of vomiting episodes and timing of episodes was not helpful in predicting ciTBI or TBI on Head CT, as there was a non-statistically significant counterintuitive trend towards less ciTBI/TBI on CT with more episodes.


    Other References

    Research PaperEaster JS, Bakes K, Dhaliwal J, Miller M, Caruso E, Haukoos JS. Comparison of PECARN, CATCH, and CHALICE rules for children with minor head injury: a prospective cohort study. Ann Emerg Med. 2014 Aug;64(2):145-52, 152.e1-5. doi: 10.1016/j.annemergmed.2014.01.030. Epub 2014 Mar 11.Research PaperBrenner D, Elliston C, Hall E, Berdon W. Estimated risks of radiation-induced fatal cancer from pediatric CT. AJR Am J Roentgenol. 2001 Feb;176(2):289-96.Research PaperDayan PS, Holmes JF, et al. Association of Traumatic Brain Injuries with Vomiting Children with Blunt Head Trauma. Ann Emerg Med. 2014; 63(6): 657-65.Research PaperDayan PS, Holmes JF, et al. Risk of Traumatic Brain Injuries in Children Younger than 24 Months with isolated Scalp Hematomas. Ann Emerg Med. 2014; 64(2): 153-62.Research PaperHess EP, Wyatt KD, Kharbanda AB, et al. Effectiveness of the head CT choice decision aid in parents of children with minor head trauma: study protocol for a multicenter randomized trial. Trials. 2014;15:253.
    Dr. Nate Kuppermann

    From the Creator

    Why did you develop the PECARN Algorithm? Was there a clinical experience that inspired you to create this tool for clinicians?
    I've been studying head injury in children for 20 years. Earlier in my career, I developed a research focus on infectious emergencies in children. When I arrived at UC Davis, however, I was greatly caring for pediatric trauma patients, as we're a huge trauma center. There was not a systematic, evidence-based way that children with trauma were being evaluated, in particular head trauma. Everyone was getting CT scans even though the rate of hemorrhage was very low; this was back in the 1990s. I had looked at the literature at the time and found no solid evidence about who needs CT scans and I was aware of radiation risks. There seem to be a gaping hole around the evidence for evaluation of the pediatric trauma patient! I thought we've got to come up with a better way to evaluate these children.
    We started with a pilot study in 1996 with about 2000 children with head trauma, and we were able to produce a fairly robust prediction rule. After that study, there was more national interest, and we were able to secure funding for a large study in PECARN. It took 2.5 years to collect the data, and now we've published over 20 important papers using it, as a result of 15 years of work!
    What pearls, pitfalls and/or tips do you have for users of the PECARN Algorithm? Are there cases in which it has been applied, interpreted, or used inappropriately?
    I'm glad you asked this. I’d like to highlight some important issues: The study is meant to help decide which children in whom a CT is NOT needed: if a child doesn't have any of the PECARN risk factors, they should rarely get a CT scan. It does not mean that if you have one risk factor, however, that you should jump to CT. If you have just one of the low-risk factors (not altered mental status, not palpable skull fracture as these are high risk factors), observation for a period of time before the decision to CT is very often the right thing to do.
    In fact, we’ve published several papers or abstracts on the risk of important TBI given isolated “low risk factors.” These include isolated scalp hematoma, isolated LOC, isolated vomiting, isolated headache, isolated "parent thinks the child is not acting right," and isolated severe mechanism -- and any by themselves are not highly predictive of intracerebral hemorrhage. You can observe many of these children, and you will not require CT on many/most, assuming they are well after a period of observation.
    What recommendations do you have for health care providers once they have applied the PECARN Algorithm? Are there any adjustments or updates you would make to the algorithm given your recent publications on isolated vomiting, for example?
    I'd really like to emphasize observation of children at low risk of TBI before the decision to CT. There's no "official" definition for the observation period after their injury, after which the child is at minimal risk of important TBI. However, 6 hours from the time of injury is a very conservative amount. Probably closer to "a few" or "several" hours. There is an excellent study by Hamilton and Johnson that suggests that after 6 hours, delayed presentation of intracranial hemorrhage is rare.
    The other thing I like to do if the child is at low risk for important TBI (i.e. has one or two intermediate risk PECARN factor) is to do shared decision-making in deciding about CT. We are in the middle of a study about this now. However, if a child has no PECARN risk factors, I don’t do shared decision making, I discharge them without CT. And ff they have one of the two high risk PECARN factors, or multiple intermediate risk factors, we will typically get a CT scan.
    What about the child who presents to the ED not acutely but subacutely -- maybe a day later with significant or severe concussive symptoms? Should those children be imaged?
    I think so -- but it really depends on their age and the clinical scenario. Children younger than 2 can have delayed presentations of TBIs due to venous epidural bleeds. If it is an older child, and if it's been 24 hours since their injury, and they do not have concerning signs for TBI, they're still neurologically intact, but have post-concussive symptoms, then an outpatient MRI is a reasonable approach. However, emergent CT is always indicated if there is concerns for acute TBI.
    Finally -- any other comments? Any new research or papers on this topic in the pipeline?
    We'll be publishing some more data from our full database by the end of 2014, so look for that soon, We're really excited about them.
    And I really love MDCalc -- you guys do a great service. We've tried implementing evidence within the EMR, and it's frequently a bit clunky and hard to use. You guys are doing great work!

    About the Creator

    Nate Kuppermann, MD, MPH, is a professor and chair of the emergency medicine department at UC Davis Children’s Hospital. He chaired the first research network in PEM and was a founding chair of the Pediatric Emergency Care Applied Research Network (PECARN). Dr. Kuppermann is a leading national investigator for studies focusing on infectious emergencies in children including the laboratory evaluation of young febrile children, the evaluation of children at risk of diabetic ketoacidosis-related cerebral injury, and the laboratory and radiographic evaluation of the pediatric trauma patient.

    To view Dr. Nate Kuppermann's publications, visit PubMed

    About the Creator
    Dr. Nate Kuppermann
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