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.

A negative urinalysis is associated with a low likelihood of intra-abdominal injury after blunt abdominal trauma.

BACKGROUND: The utility of urinalysis (UA) to diagnose intra-abdominal (IA) or genitourinary (GU) injury after blunt trauma remains controversial. The purpose of this study was to determine the significance of UA in the blunt trauma patient. METHODS: A retrospective review of patients admitted for blunt abdominal trauma from 2011 to 2013. RESULTS: A total of 1,795 patients sustained blunt abdominal trauma: mean age of 44 ± 21 years; mean Injury Severity Score of 13 ± 10. Overall 810 patients had a negative UA (45%). Two patients (2/810 and .2%) had a GU injury and neither required intervention. Thirty-two patients (32/810 and 4.0%) had an IA injury, and 2 (2/810 and .02%) required intervention. The sensitivity for predicting GU injury requiring intervention was 1, and IA injury requiring intervention was .96. Negative predictive values were 1 and .99. CONCLUSIONS: A negative UA correlates with a low risk for GU and IA injury after blunt abdominal trauma. A negative UA should be evaluated prospectively as part of a clinical prediction score to rule out injury and avoid unnecessary radiation exposure from computed tomography imaging.

Determination of urinary N-acetyl-ß-D glucosaminidase (NAG) levels in experimental blunt renal trauma.

BACKGROUND: We evaluated the applicability of urinary N-acetyl-beta-D glucosaminidase (NAG) levels in the diagnosis and follow-up in blunt kidney injury. METHODS: Twenty Sprague-Dawley rats were studied. In the Sham group, left kidney exploration was made. In the Trauma group, after left kidney exploration, a 20 g weight was dropped onto the kidneys. Urine was collected for analysis with strip and determination of urinary NAG and creatinine (Cr) levels at baseline and 0-6, 12-24, 24-36 and 36-48 postoperative hours. Mann-Whitney U and Kruskal-Wallis tests were used. RESULTS: Macroscopic examinations of traumatized kidneys revealed grade II and III injury, and histopathological examinations showed relevant changes. Macroscopic hematuria was observed in all traumatized rats. Urinary NAG/Cr levels in the Trauma group were found to be significantly higher than their base levels at 0-6, 12-24, 24-36, and 36-48 hours. In the Sham group, only the level of NAG/Cr at 0-6 hours was significantly higher. The increase in NAG/Cr levels at 0-6 hours was significantly higher in the Trauma group than in the Sham group. CONCLUSION: After isolated blunt renal trauma, urinary NAG levels increase in the early stage. However, more detailed clinical studies are needed to develop NAG levels as a criterion in the follow-up of blunt renal trauma.

Prospective comparison of microscopic and gross hematuria as predictors of bladder injury in blunt trauma.

OBJECTIVES: The evaluation of the genitourinary system in patients with blunt trauma remains controversial. Historically, patients with more than 50 red blood cells on urinalysis underwent additional genitourinary imaging. Retrospective studies have demonstrated that bladder injury is almost always associated with gross hematuria. We have prospectively demonstrated that bladder imaging is required for gross hematuria and unnecessary for microscopic hematuria. METHODS: Patients sustaining blunt trauma with hematuria were prospectively evaluated during a 3-year period. During the first 18 months of the study (first treatment arm), patients with microscopic hematuria (more than 50 red blood cells on urinalysis) underwent bladder imaging. During the second 18 months, patients underwent bladder imaging only for gross hematuria. RESULTS: A total of 8026 patients were evaluated. In the first arm, 214 patients underwent cystography for microscopic hematuria, and no bladder injuries were identified; 78 patients underwent cystography for gross hematuria, and 21 bladder injuries were identified. Chi-square analysis revealed no difference in the presence of microscopic hematuria to predict for bladder injury. In the second arm, 308 patients presented with microscopic hematuria, none of whom underwent cystography, and 91 patients underwent cystography for gross hematuria, with 15 bladder injuries identified. The presence of gross hematuria demonstrated 100% sensitivity and 98.5% specificity as a screening test for bladder injury. No bladder injuries were missed. CONCLUSIONS: The results of our study have shown that the presence of gross hematuria warrants evaluation of the bladder. The presence of gross hematuria demonstrated improved sensitivity, specificity, positive predictive value, negative predictive value, and accuracy over the presence of microscopic hematuria in the detection of bladder injury. Using gross hematuria as an indication for bladder imaging will eliminate unnecessary imaging without compromising the quality of patient care.