title: Head injury and unclear mechanism of injury: initial hematocrit less than 30 is predictive of abusive head trauma in young children.
abstract: OBJECTIVE
  Head injury secondary to abusive head trauma (AHT) is a major cause of morbidity and mortality in susceptible young infants and children. Diagnosing AHT remains challenging and is often complicated by a questionable mechanism of injury. Concern of ionizing radiation risk to children undergoing head CT imaging warrants a selective approach. We aimed to evaluate initial findings that could direct further investigation of AHT.
  
  
  METHODS
  A retrospective review of the trauma databases at a two level one pediatric trauma centers was performed. We reviewed all patients age five years and under with a diagnosis of traumatic brain injury (TBI) from 2002-2011.
  
  
  RESULTS
  A total of 1129 patients (mean age 1.7 ± 1.7 years; 64% male) with TBI were identified, 429 (38%) of which were the result of AHT. Complete data was available for 921 patients (82%) and were included in statistical evaluation. Forty-eight percent of patients in the AHT group had a hematocrit ≤ 30% on presentation compared to 19% of patients in the non-AHT group. On univariate analysis, a hematocrit of ≤ 30% was predictive of AHT as the cause of injury (P<.0001), as was a platelet count of greater than 400,000 (P<.0001). After controlling for age, sex, ISS, GCS on presentation, need for CPR, and survival to hospital discharge, hematocrit of ≤ 30% and platelets of greater than 400,000 were predictive of AHT as the cause of TBI (P<.05).
  
  
  CONCLUSIONS
  In the setting of head injury and unclear history of trauma, a hematocrit of ≤ 30% on presentation increases the likelihood of abusive head trauma in children up to the age of 5 years.
authors: Department of Pediatric Surgery, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA.
authors: Shannon N
authors: SN
authors: Acker
authors: Department of Pediatric Surgery, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA.
authors: David A
authors: DA
authors: Partrick
authors: Department of Pediatric Surgery, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA.
authors: James T
authors: JT
authors: Ross
authors: Department of Pediatric Surgery, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA.
authors: Nicole A
authors: NA
authors: Nadlonek
authors: Department of Surgery, Surgical Outcomes and Applied Research, University of Colorado School of Medicine, Aurora, CO, USA.
authors: Michael
authors: M
authors: Bronsert
authors: Department of Pediatric Surgery, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, USA; Department of Surgery, Denver Health & Hospital Authority, Denver, CO, USA. Electronic address: denis.bensard@dhha.org.
authors: Denis D
authors: DD
authors: Bensard
mesh_terms: D002649:Child Abuse / Q000175:diagnosis*; D003120:Colorado; D006259:Craniocerebral Trauma / Q000097:blood* / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006400:Hematocrit; D006801:Humans; D007223:Infant; D008297:Male; D011237:Predictive Value of Tests; D012042:Registries; D012189:Retrospective Studies; D014193:Trauma Centers; D015599:Trauma Severity Indices
keywords: Abusive head trauma; Anemia; Traumatic brain injury