MDCalc

Pediatric NEXUS II Head CT Decision Instrument for Blunt Trauma

Predicts need for head CT after pediatric blunt head injury, similar to PECARN.

Use in patients <18 years old who have sustained blunt head trauma within the past 24 hours and in whom head CT is being considered. 

Note: We recommend using PECARN over other pediatric head trauma rules, as it is the most widely validated (see Next Steps for details).

Criteria

e.g. periorbital or periauricular ecchymoses, hemotympanum, drainage of clear fluid from ears or nose, palpable step-off, stellate laceration (see Evidence for more detail)
Injuries not involving calvarium (e.g. hematomas limited to the face/neck) are not considered scalp hematomas
Any abnormal neurologic finding revealed by detailed exam (see Evidence for more detail)
e.g. GCS ≤14; delayed or inappropriate response to external stimuli; excessive somnolence; disorientation to person, place, time, or events; inability to remember three objects at 5 mins; perseverating speech
Any inappropriate action, e.g. excessive agitation, inconsolability, refusal to cooperate, lack of affective response to questions or events, violent activity
Recurrent projectile or forceful emesis (>1 episode), either observed or by history, after trauma
Any clotting impairment, e.g. hemophilia, secondary to medications (Coumadin, heparin, aspirin, etc), hepatic insufficiency

Diagnostic Result

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Advice
  • In low risk populations, we would recommend using other externally validated tools to determine the necessity of head CT in pediatric blunt head trauma patients (i.e., PECARN).
  • Our recommendation for the PECARN Head Injury Algorithm is based partly on the fact that it enrolled the largest number of patients during its derivation and validation (33,785 in derivation cohort and 8,627 in the validation cohort). This compares to 22,772 enrolled in the original CHALICE study, 3,866 patients for the CATCH Rule, and 1,018 subjects enrolled in Pediatric NEXUS II Head CT instrument.
  • PECARN also has the highest negative predictive value (NPV) (100% and 99.95% for children <2 and ≥2 years-old, respectively). That said, the NPV of the CHALICE (99.8%) and CATCH (99.9%) rules are also excellent and present additional reasonable options.

Negative:

  • Patients who do not meet criteria for imaging should always be counseled about the following:
  • Concussion and its symptoms.
  • Strict head injury return precautions (e.g. vomiting, somnolence/altered mental status).
  • Many still recommend a period of observation after head injury.

Positive:

  • Patients who meet criteria for head CT may have intracerebral hemorrhage or they may not; however, if the criteria of the instrument are met, head CT is recommended.
Critical Actions

Remember, this decision instrument was only applied to a population of pediatric patients in which clinicians were intending on performing head CT. This may have eliminated a clinically “low risk” group of patients (i.e., GCS 15). Thus, applying this instrument to this population is not recommended.

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