Differentiation of acute pyelonephritis from other febrile states in children using urinary neutrophil gelatinase-associated lipocalin (uNGAL).

BACKGROUND: Acute pyelonephritis is a severe disease which is sometimes difficult to recognize based on clinical symptoms and routinely available diagnostic tests, especially in young children. The aim of this study was to assess the diagnostic value of urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a biomarker of acute pyelonephritis. METHODS: In this case-control study we analyzed 134 children (median age 2.5 years) who were admitted to the Pediatric Clinic of University Hospital Centre Osijek, Croatia. Eighty of them had acute pyelonephritis, while 54 children had febrile state of different etiology including cystitis and they represented the control group. uNGAL, white blood cells, C-reactive protein, urinanalysis, urine culture, kidney ultrasound and a dimercaptosuccinic acid scintigraphic scan were done for each child. uNGAL was measured using chemiluminiscent microparticle immunoassay on ARHITECT i1000SR (Abbott Diagnostics, IL, USA). RESULTS: uNGAL values were significantly higher in children with acute pyelonephritis compared to the control groups (113.6 ng/mL vs. 10.2 ng/mL, p<0.001). A receiver operating characteristic curve comparison was done for tested parameters and encouraging results were obtained for uNGAL (AUC=0.952). A cut-off value of 29.4 ng/mL had 92.5% sensitivity and 90.7% specificity. We showed that uNGAL can also serve in differentiating acute pyelonephritis from cystitis (cut-off 38.5 ng/mL), and for differentiation of cystitis from febrile states with etiology other than urinary tract infection (UTI) (cut-off 20.4 ng/mL). CONCLUSIONS: uNGAL can be a useful diagnostic biomarker in acute pyelonephritis in children, but also in differentiating cystitis from febrile states other than UTI.

[The value of Tc99m-DMSA renal scintigraphy in evaluation of severity of parenchymal lesions in children with acute urinary tract infection]. / Vrijednost Tc99m-DMSA scintigrafije bubrega u djece s akutnom uroinfekcijom u procjeni tezine parenhimskih lezija.

INTRODUCTION: Most authors would agree that renal parenchymal defects (scars, hypoplasia, dysplasia) in children are a major risk factor for chronic renal failure, and for development of systemic hypertension in later years. The pathophysiologic changes in acute pyelonephritis include tubulointerstitial inflammation/pus with impairment of the renal microcirculation due to compression of the glomeruli, small peritubular capillaries and vasa recta by interstitial edema. The resulting ischemia has been postulated as one of the mechanisms for the decreased accumulation of DMSA in the areas of pyelonephritis. DMSA scanning has a sensitivity of up to 99%, and specificity of up to 91% for the detection of acute pyelonephritis. AIM OF THE STUDY: The aim of the study was to investigate the value of Tc99m-DMSA scan in children with acute urinary tract infection, to estimate the degree of parenchymal changes, and to assess the relationship with vesicoureteral reflux. PATIENTS: We reviewed 116 infants aged 0-15 years, 100 (86.2%) female and 16 (13.8%) male, who were hospitalized for urinary tract infection during a 5-year period (1996-2000). The mean age at diagnosis was 3.7 years. RESULTS: Escherichia colli was isolated in 52 (44.8%) urine cultures. All patients underwent ultrasonography, which was normal in 57 (49.1%) infants. Tc99m-DMSA was performed after two weeks of therapy. The renal parenchymal pathology was defined as a focal or multifocal defect of low degree in 33 (28.4%), and of high degree in 35 (30%) children. Multifocal defects were mostly found in patients aged < 3 years, and focal lesions in those aged > 3 years. Renal scars were detected in 41 (35.3%) infants with first urinary tract infection. CONCLUSION: We recommend that ultrasound, DMSA and radionuclide cystouretherogram be routinely performed in case of first urinary tract infection in infants aged < 1 year, and voiding cystourethrogram with US and DMSA in those aged > 1 year.

[Rare renal anomalies in childhood]. / Rijetka anomalija bubrega u djecjoj dobi.

Three patients with megacalycosis, a rare ren anomaly which includes dilatation of all ren calices, are presented. The symptoms of acute uroinfection were present in all three patients. The patients underwent clinical observation, laboratory testing, and renal ultrasound. Ultrasound revealed unilateral hydronephrosis in all three patients. Additional examinations included static and dynamic renal scintigraphy, voiding cystourethrography, and intravenous urography which pointed to unilateral megacalycosis. The symptoms of acute uroinfection were probably triggered by urinary stasis in dilated calices. Surgical intervention is not indicated in megacalycosis. The increasing incidence of uroinfection, urolithiasis and hematuria imposed the need of continuous follow-up in these patients.