Does Microscopic Hematuria After Pediatric Blunt Trauma Indicate Clinically Significant Injury?

Background: Children are more likely to have urinary system injury after blunt abdominal trauma (BAT) because of anatomical vulnerabilities. Urinalysis (UA) is often performed during initial evaluation to screen for injury. The purpose of this study was to determine how often finding microscopic hematuria after BAT leads to further testing and whether this indicates a significant injury. Methods: A retrospective review of children evaluated for BAT at Children's Health from 2013 to 2017 was performed. Patients included had microscopic hematuria on initial UA. Data collected included demographics, injury data, laboratory and imaging data, and outcomes. Analysis was performed using descriptive statistics, Fisher's exact, and independent t-test. Results: Of 1059 patients treated for BAT during the study period, 203 (19%) exhibited microscopic hematuria on UA during the initial workup. Most UAs resulted after imaging was completed and did not impact management (158, 78%); twenty-two (14%) of these patients had urinary injury, which were diagnosed by imaging regardless of UA results. Forty-five (22%) patients were found to have microscopic hematuria that independently led to workup for urinary injury. Of these, nine patients had a urinary system injury: 6 low-grade renal and three bladder wall injuries, none of which required surgery. Those with and without urinary injury in this group underwent similar numbers of radiographic studies. Conclusions: Microscopic hematuria on screening UA after BAT may lead to extensive workup, regardless of the presence of symptoms. In patients who receive cross-sectional abdominal imaging, preceding UA adds little to the clinical workup of children with BAT.