Clinical and laboratory indices of severe renal lesions in children with febrile urinary tract infection

Serum Calprotectin Is a Valid Biomarker in Distinction of Bacterial Urinary Tract Infection From Viral Respiratory Illness in Children Under 3 Years of Age

BACKGROUND

Febrile illnesses in young children can be a major diagnostic challenge, despite the routine use of various laboratory markers. Recent advancements in the understanding of inflammatory processes have highlighted the role of calprotectin, a heterodimer consisting of S100A8 and S100A9 proteins, with many studies suggesting its clinical value as a biomarker of inflammation. This research aimed to evaluate the usefulness of serum calprotectin (sCal) as a biomarker of urinary tract infection (UTI), which was due to its high pooled prevalence and feasibility of urine culture as a diagnostic reference standard selected for a model of bacterial infection in children.

METHODS

Febrile children aged 0-36 months with suspected UTI based on positive urinalysis or viral respiratory tract infection were included. Children with significant bacteriuria in urine culture were labeled as cases (n = 58), while those with confirmed viral infection (n = 51), as well as those with suspected UTI but sterile urine culture who went on to develop symptoms consistent with viral respiratory infection (n = 7), were labeled as controls. sCal levels were determined by a commercial immunoassay. Conventional inflammation markers (C-reactive protein, procalcitonin, white blood cell count, absolute neutrophil count, and neutrophil percentage) were measured on the day of the clinical examination. Differences in measured inflammatory markers between cases and controls were analyzed with Mann-Whitney U-test. ROC analysis reported cut-off values with the best sensitivity and specificity to distinguish bacterial UTI from viral respiratory infection.

RESULTS

All analyzed inflammatory biomarkers, including sCal, were significantly higher in cases than in controls. Median concentration of sCal was 4.97 μg/mL (IQR 3.43-6.42) and 2.45 μg/mL (IQR 1.63-3.85) for cases and controls, respectively (p < 0.001). For identifying bacterial UTI, sensitivity and specificity of sCal were 77.6 and 69.0%, respectively, at an adjusted cut-off point of >3.24 μg/mL (AUC 80.2%).

CONCLUSION

sCal could have substantial added value in the management of a child with fever and positive urinalysis and is a promising biomarker in distinction between bacterial UTI and viral respiratory causes of febrile illness in children under the age of 3 years.

Procalcitonin, C-reactive protein, and erythrocyte sedimentation rate for the diagnosis of acute pyelonephritis in children

BACKGROUND

In children with urinary tract infection (UTI), only those with pyelonephritis (and not cystitis) are at risk for developing long-term renal sequelae. If non-invasive biomarkers could accurately differentiate children with cystitis from children with pyelonephritis, treatment and follow-up could potentially be individualized. This is an update of a review first published in 2015.

OBJECTIVES

The objectives of this review were to 1) determine whether procalcitonin (PCT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) can replace the acute DMSA scan in the diagnostic evaluation of children with UTI; 2) assess the influence of patient and study characteristics on the diagnostic accuracy of these tests, and 3) compare the performance of the three tests to each other.

SEARCH METHODS

We searched MEDLINE, EMBASE, DARE, Web of Science, and BIOSIS Previews through to 17th December 2019 for this review. The reference lists of all included articles and relevant systematic reviews were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We only considered published studies that evaluated the results of an index test (PCT, CRP, ESR) against the results of an acute-phase ⁹⁹Tc-dimercaptosuccinic acid (DMSA) scan (conducted within 30 days of the UTI) in children aged 0 to 18 years with a culture-confirmed episode of UTI. The following cut-off values were used for the primary analysis: 0.5 ng/mL for procalcitonin, 20 mg/L for CRP and 30 mm/hour for ESR.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria to all citations and independently abstracted data. We used the bivariate model to calculate pooled random-effects pooled sensitivity and specificity values.

MAIN RESULTS

A total of 36 studies met our inclusion criteria. Twenty-five studies provided data for the primary analysis: 12 studies (1000 children) included data on PCT, 16 studies (1895 children) included data on CRP, and eight studies (1910 children) included data on ESR (some studies had data on more than one test). The summary sensitivity estimates (95% CI) for the PCT, CRP, ESR tests at the aforementioned cut-offs were 0.81 (0.67 to 0.90), 0.93 (0.86 to 0.96), and 0.83 (0.71 to 0.91), respectively. The summary specificity values for PCT, CRP, and ESR tests at these cut-offs were 0.76 (0.66 to 0.84), 0.37 (0.24 to 0.53), and 0.57 (0.41 to 0.72), respectively.

AUTHORS' CONCLUSIONS

The ESR test does not appear to be sufficiently accurate to be helpful in differentiating children with cystitis from children with pyelonephritis. A low CRP value (< 20 mg/L) appears to be somewhat useful in ruling out pyelonephritis (decreasing the probability of pyelonephritis to < 20%), but unexplained heterogeneity in the data prevents us from making recommendations at this time. The procalcitonin test seems better suited for ruling in pyelonephritis, but the limited number of studies and the marked heterogeneity between studies prevents us from reaching definitive conclusions. Thus, at present, we do not find any compelling evidence to recommend the routine use of any of these tests in clinical practice.

Fever duration during treated urinary tract infections and development of permanent renal lesions

OBJECTIVE

To assess the effect of the duration of fever after the initiation of treatment (FAT) of febrile urinary tract infections (UTI) on the development of permanent renal lesions based on dimercaptosuccinic acid (DMSA) scintigraphy findings. To evaluate the FAT contribution to permanent renal lesion formation in relation to fever before treatment initiation (FBT), the presence of vesicourinary reflux (VUR), age and severity of infection.

METHODS

The inpatient records of 148 children (median age: 2.4 months (11 days to 24 months)) with a first episode of UTI during a 3-year period were analysed. DMSA findings, and clinical and laboratory parameters were evaluated.

RESULTS

Among the study population, 34/148 (22.97%) children had permanent renal lesions on the DMSA scan 6 months after a single episode of UTI. Twenty-three children (15.5%) had mild, 10 (6.7%) had moderate and 1 (0.6%) child had severe lesions on the DMSA. FAT prolongation >/48 hours was associated with older age (p=0.01) and increased absolute neutrophil count (p=0.042). The likelihood of lesions was significantly increased when FAT was ≥48 hours (R²=0.043, p=0.021). On multiple regression analysis, with the addition of FBT>/72 hours (0.022), the presence of VUR (p<0.001), C-reactive protein (p=0.027) and age (p=0.031), the effect of FAT on lesion development disappeared (p=0.15).

CONCLUSIONS

Prolongation of FAT≥48 hours of febrile UTI in children <2 years significantly contributes to the development of permanent renal lesions. However, delay in treatment initiation >/72 hours, the presence of VUR, older age and infection severity seem to be more significant predictors of the development of renal lesions.

The value of delta neutrophil index in young infants with febrile urinary tract infection

Delta neutrophil index (DNI) is the fraction of circulating immature granulocytes, which reflects severe bacterial infections and septic condition but has not been studied in urinary tract infection (UTI). Here, we evaluated the value of DNI in predicting acute pyelonephritis (APN) or vesicoureteral reflux (VUR) using the data of 288 patients. Conventional inflammatory markers (white blood cell [WBC] count, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]), and DNI were measured. WBC, CRP, ESR and DNI were higher in APN than in lower UTI (p < 0.01). Multiple logistic-regression analyses showed that DNI was a predictive factor for areas of lack of uptake on dimercaptosuccinic acid (DMSA) scans (P < 0.01). The area under the receiver operating characteristic (AUC) was also high for DNI (0.622, 95% CI 0.558-0.687, P < 0.01) as well as for CRP (0.731, 95% CI 0.673-0.789, P < 0.01) for the prediction of DMSA defects. DNI demonstrated the highest area under the ROC curve for diagnosis of VUR (0.620, 95% CI 0.542-0.698, P < 0.01). To the best of our knowledge, this is a first study demonstrating that DNI can be used as a diagnostic marker to distinguish APN from lower UTI and function as a diagnostic marker indicative of VUR compared to other conventional markers.

Delayed treatment of the first febrile urinary tract infection in early childhood increased the risk of renal scarring

AIM

This study evaluated the controversial relationship between the duration of fever before treatment initiation (FBT) for a febrile urinary tract infection (UTI), with renal scarring based on dimercaptosuccinic acid scintigraphy (DMSA) findings.

METHODS

The inpatient records of 148 children under two years of age with a first episode of febrile UTI were analysed. Acute and repeat DMSA findings, and clinical and laboratory parameters were evaluated.

RESULTS

Acute DMSA showed that 76 of the 148 children with a febrile UTI had renal lesions: 20 were mild, and 56 were moderate or severe. Repeat DMSA showed renal scarring in 34 patients. The only factors associated with the development of renal scars in the repeat DMSA were FBT of more than 72 hours, the presence and severity of vesicoureteral reflux and increased procalcitonin levels and absolute neutrophil counts. Multiple regression analysis showed that an FBT above 72 hours was the only significant factor that predicted renal scars.

CONCLUSION

Delay in treatment initiation of 72 hours or more was a risk factor for permanent renal scars after the first episode of febrile UTI. Other associated factors were increased procalcitonin and absolute neutrophil count on admission and the presence and severity of vesicouretal reflux.

Usefulness of neutrophil-lymphocyte ratio in young children with febrile urinary tract infection

PURPOSE

Acute pyelonephritis (APN) is a serious bacterial infection that can cause renal scarring in children. Early identification of APN is critical to improve treatment outcomes. The neutrophil-lymphocyte ratio (NLR) is a prognostic marker of many diseases, but it has not yet been established in urinary tract infection (UTI). The aim of this study was to determine whether NLR is a useful marker to predict APN or vesicoureteral reflux (VUR).

METHODS

We retrospectively evaluated 298 pediatric patients (age≤36 months) with febrile UTI from January 2010 to December 2014. Conventional infection markers (white blood cell [WBC] count, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]), and NLR were measured.

RESULTS

WBC, CRP, ESR, and NLR were higher in APN than in lower UTI (P<0.001). Multiple logistic regression analyses showed that NLR was a predictive factor for positive dimercaptosuccinic acid (DMSA) defects (P<0.001). The area under the receiver operating characteristic (ROC) curve was high for NLR (P<0.001) as well as CRP (P<0.001) for prediction of DMSA defects. NLR showed the highest area under the ROC curve for diagnosis of VUR (P<0.001).

CONCLUSION

NLR can be used as a diagnostic marker of APN with DMSA defect, showing better results than those of conventional markers for VUR prediction.