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.

Assessment of urinary dipstick in patients admitted to an ED for blunt abdominal trauma.

INTRODUCTION: Clinicians still face significant challenge in predicting intra-abdominal injuries in patients admitted to an emergency department for blunt abdominal trauma. This study was thus designed to investigate the value of dipstick urinalysis in patients with blunt abdominal trauma. METHODS: We performed a retrospective, multicenter, cohort study involving patients admitted to the emergency department for abdominal traumas, examined by means of urinary dipstick and abdominal CT scan. The primary endpoint was the correlation between microscopic hematuria detected via dipstick urinalysis (defined by the presence of blood on the dipstick urinalysis but without gross hematuria) and abdominal injury, as evidenced on CT scan. RESULTS: Of the 100 included patients, 56 experienced microscopic hematuria, 17 gross hematuria, and 44 no hematuria. Patients with abdominal injury were more likely to present with hypovolemic shock (odds ratio [OR]: 8.4; 95% confidence interval [CI]: 2.7-26), abdominal wall hematoma (OR: 3.1; 95% CI: 1.2-7.9), abdominal defense (OR: 5.2; 95% CI: 1.8-14.5), or anemia (OR: 3.6; 95% CI: 1.2-10.3). Moreover, dipstick urinalysis was less likely to predict injury, with just 72.2% sensitivity (95% CI: 54.8-85.8), 53.1% specificity (95% CI: 40.2-65.7), and positive and negative predictive values of 46.4% (95% CI: 33.0-60.3) and 77.3% (95% CI: 62.2-88.5), respectively. CONCLUSION: Dipstick urinalysis was neither adequately specific nor sensitive for predicting abdominal injury and should thus not be used as a key assessment component in patients suffering from blunt abdominal trauma, with physical exam and vital sign assessment the preferred choice.

Routine urinalysis in patients with a blunt abdominal trauma mechanism is not valuable to detect urogenital injury.

OBJECTIVE: To investigate whether the routine performance of urinalysis in patients with a blunt trauma mechanism is still valuable. METHODS: Consecutive patients aged ≥16 years, admitted to a Dutch Level 1 trauma centre between January 2008 and August 2011, were included in this retrospective cohort study. Results of urinalysis (erythrocytes per µL) were divided into no, microscopic or macroscopic haematuria. Patients were divided into four groups based on whether a urinalysis was performed or not, with or without imaging for urogenital injury. Main outcome measures were the presence of urogenital injury and whether the findings on urine specimen and/or imaging led to clinical consequences. RESULTS: A total of 1815 patients were included. The prevalence of intra-abdominal and urogenital injuries was 13% and 8%, respectively. In 1363 patients (75%), urinalysis was performed and 1031 patients (57%) underwent imaging for urogenital injury as well. The presence of macroscopic haematuria (n=16) led to clinical consequences in 73% of the patients (11 out of 15), regardless of the findings on imaging. Microscopic haematuria on urinalysis in combination with no findings on imaging led to clinical consequences in 8 out of 212 patients (4%). Microscopic haematuria on urinalysis in patients who did not have imaging for urogenital injury did not lead to clinical consequences (0 out of 54 patients; 0%). All the 8 patients who underwent an intervention had positive findings on imaging. CONCLUSIONS: The results do not support the routine performance of urinalysis in patients admitted with a blunt trauma mechanism. Although urinalysis could be valuable in specific patient populations, we should consider omitting this investigation as a routine part of the assessment of trauma patients.

Microscopic hematuria as a marker of blunt abdominal trauma in rats: description of an experimental model.

BACKGROUND: Microscopic hematuria is an extremely important sign in blunt abdominal trauma (BAT) patients. Controversies still exist in the literature on whether microscopic hematuria is a sign of intra-abdominal extrarenal organ injury and is an indication for radiographic assessment of BAT patients. In this study, a new BAT rat model was developed, and we tried to determine the relationships between microscopic hematuria and extrarenal intra-abdominal organ injury. METHODS: After verifying our model, lethal and maximal sublethal intensity of impact energy determined in the rats. Animals allocated into six sublethal impact energy groups. BAT was induced by dropping a standard mass from variable heights. After 2 hours of examining period, macroscopic laparotomy findings, histopathological liver, spleen and renal injury grades, and microscopic hematuria levels were recorded in these six groups. RESULTS: According to our results, while the trauma intensity increase severity of the histopathological injury increases for all organs. Although there was a significant correlation between microscopic hematuria and trauma intensity, we could not show same relationship between microscopic hematuria and histopathological organ injury. On the other hand, microscopic hematuria was correlated with the macroscopic laparotomy findings. CONCLUSIONS: Microscopic hematuria could serve as a predictor of the severity of trauma and intra-abdominal organ injury. This study would support the use of abdominal imaging and attentive assessment for intra-abdominal organ injury in stable BAT patients with hematuria. The laparotomy threshold may be lowered for unstable BAT patients with hematuria.

Utility of screening urinalysis to detect abdominal injuries in suspected victims of child physical abuse.

BACKGROUND: Urinalysis, liver enzymes (LE) and lipase are used to screen for abdominal injuries in children with suspected physical abuse (SPA). However, data on the utility of urinalysis is limited. OBJECTIVES: Describe the prevalence of hematuria in evaluations for SPA. Determine test characteristics of hematuria, LE and lipase to identify kidney and other abdominal injuries among children with SPA. PARTICIPANTS AND SETTING: Children < 7 years receiving a urinalysis during evaluation for SPA by a hospital child protection team. METHODS: Demographic, clinical, and laboratory data including presence of hematuria (blood on urine dipstick), elevated LE (> 80 U/L) and elevated lipase (> 100 U/L) were abstracted retrospectively. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the overall study population and for patients without abdominal symptoms. RESULTS: Ten percent of patients had hematuria (N = 237). Prevalence of abdominal and kidney injuries was 7 % and 1 % respectively. Of 3 patients with kidney injury, 2 had hematuria and all had elevated LE. Sensitivity (67 %) and NPV (99 %) of hematuria to detect kidney injuries were lower than LE and the same as lipase. Specificity (91 %) and PPV (8%) of hematuria to detect kidney injury were greater than LE and similar to lipase. Sensitivity of hematuria to detect any abdominal injury (50 %) was lower than LE (81 %). Sensitivity of hematuria to detect occult abdominal injury was 0 %. CONCLUSIONS: Hematuria alone did not lead to detection of kidney injury. Test characteristics of hematuria were largely similar or inferior to LE and lipase.

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.

The use of routine laboratory studies as screening tools in pediatric abdominal trauma.

BACKGROUND: Standard laboratory panels were shown to play an important role in the evaluation of pediatric blunt abdominal trauma before the routine use of computed tomography (CT) scan. Recently, only a few relatively limited studies have evaluated the use of these "trauma panels." OBJECTIVE: To evaluate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of routine "trauma panels" for evaluating intra-abdominal injury in pediatric blunt trauma patients. METHOD: We undertook a retrospective medical record review of all children with potential major blunt abdominal trauma who entered the Children's Hospital (Boston, MA) trauma registry from July 1996 to August 1999. Routine laboratory tests during those years included sodium, glucose, white blood cell count, hematocrit, platelets, prothrombin time, activated partial thromboplastin time, aspartate aminotransferase (AST), alanine aminotransferase, amylase, lipase, and urinalysis. Individual findings were considered abnormal if they fell out of the laboratory's respective reference range. We determined sensitivity, specificity, PPV, NPV, and the 95% confidence interval for each test, using abdominal pathology identified by CT scan as the gold standard. RESULTS: Three hundred eighty-two patients were included. Of that, 68% were men. Median age was 115 months (intraquartile range, 60-159 months). In total, 241 of the patients (63%) had an abdominal CT scan performed, 83 of which (33%) had abnormal findings. Abnormal values for glucose, AST, urinalysis, and white blood cell count were the most frequently observed abnormalities (67%, 47%, 43%, and 43%, respectively). Among the 83 patients with abdominal pathology, glucose and AST had the highest sensitivity (75% and 63%, respectively). Lipase had the highest PPV at 75%, and AST had the highest negative predictive at 71%. No routine laboratory test had excellent sensitivity, specificity, PPV, and NPV. CONCLUSIONS: Routine "trauma panels" should not be obtained as a screening tool in children with blunt trauma being evaluated for intra-abdominal injury.

Lipiduria after intralipid infusion of a lipid emulsion in a boy with an abdominal trauma.

A 4-year-old boy with an abdominal trauma had lipiduria following treatment with total intravenous nutrition for 4 days. Renal function was normal throughout the course and the lipiduria ceased after withdrawal of the intravenous nutrition. The lipids were possibly excreted through the kidneys or entered the urine through a traumatic communication between the lymphatic vessels and the urinary system. Control of renal function and lipiduria after 1 year revealed normal conditions.

Urine dipstick vs. microscopic urinalysis in the evaluation of abdominal trauma.

This study was designed to assess the accuracy of the urine dipstick and its ability to predict injury to the urinary tract when compared to routine urinalysis: 1,485 patients had dipstick and microscopic urinalysis performed as part of their evaluation for blunt and penetrating trauma. Dipstick analysis was recorded as either positive or negative. Microhematuria was defined as greater than 0-1 RBC/HPF on microscopic analysis. Blunt trauma accounted for 1,347 (91%) of the patients and penetrating injuries accounted for 138 cases (9%): 1,209 (81.4%) of the specimens were dipstick negative, and 276 (18.6%) were dipstick positive. False negative results, consisting of a negative dipstick reading and greater than 1 RBC/HPF on microscopic analysis occurred in 100 (6.9%) of the cases. False positive dipstick readings occurred in 64 (4.3%) of the patients. There were no cases of a missed injury in the group of 100 false negatives. Cost savings by conversion to the use of dipsticks would have saved our institution about $63,000 per year. It is concluded that the urinary dipstick is a safe, accurate, and reliable screening test for the presence or absence of hematuria in patients sustaining either blunt or penetrating abdominal trauma.

Urinary lactic dehydrogenase as a marker of renal injury in blunt trauma patients with hematuria.

We evaluated the use of urinary lactic dehydrogenase (LDH) in predicting renal injury in a convenience sample of 36 blunt trauma patients with hematuria. The mean +/- SEM urinary LDH for the five patients with renal injuries was 129.4 +/- 35 U/L, which was not significantly different from the mean urinary LDH levels in either the 22 patients without demonstrable genitourinary or retroperitoneal injuries (92.9 +/- 20.7 U/L) or the nine patients with nonrenal genitourinary or retroperitoneal injuries (165 +/- 46 U/L). Urinary LDH at a threshold of 135 U/L was more specific (75% vs 53%, P less than .01) and more accurate (74% vs 57%, P less than .01) than hematuria at a threshold of 50 red blood cells per high-power field in predicting lacerations of the kidney or ureter; urinary LDH was less sensitive than hematuria at these thresholds (67% vs 100%), but not significantly. We conclude that urinary LDH is a nonspecific marker of cellular disruption anywhere along the genitourinary tract in otherwise healthy blunt trauma patients.