Procalcitonin and vesicoureteral reflux in children with urinary tract infection

[Procalcitonin, a useful biomarker in pediatric urinary tract infection]

Urinary tract infections (UTIs) are one of the most common sources of bacterial infections among young febrile children. Accurate diagnosis of acute pyelonephritis (APN) and vesico-ureteral reflux (VUR) are important because of their association with renal scarring, sometimes leading to long-term complications. However, the gold standard examinations are either a DMSA scan for APN and scarring, or cystography for VUR, but both present limitations (feasibility, pain, cost, etc.). Procalcitonin, a reliable marker of bacterial infections, was demonstrated to be a good predictor of renal parenchymal involvement in the acute phase and in late renal scars, as well as of high-grade VUR. These findings need further broad validations and impact studies before being implemented into daily practice. However, procalcitonin may play a role in the complex and still debated picture of which examination should be performed after UTI in children.

Procalcitonin is a predictor for high-grade vesicoureteral reflux in children: meta-analysis of individual patient data

OBJECTIVE

To assess the predictive value of procalcitonin, a serum inflammatory marker, in the identification of children with first urinary tract infection (UTI) who might have high-grade (≥3) vesicoureteral reflux (VUR).

STUDY DESIGN

We conducted a meta-analysis of individual data, including all series of children aged 1 month to 4 years with a first UTI, a procalcitonin (PCT) level measurement, cystograms, and an early dimercaptosuccinic acid scan.

RESULTS

Of the 152 relevant identified articles, 12 studies representing 526 patients (10% with VUR ≥3) were included. PCT level was associated with VUR ≥3 as a continuous (P = .001), and as a binary variable, with a 0.5 ng/mL preferred threshold (adjusted OR, 2.5; 95% CI, 1.1 to 5.4). The sensitivity of PCT ≥0.5 ng/mL was 83% (95% CI, 71 to 91) with 43% specificity rate (95% CI, 38 to 47). In the subgroup of children with a positive results on dimercaptosuccinic acid scan, PCT ≥0.5 ng/mL was also associated with high-grade VUR (adjusted OR, 4.8; 95% CI, 1.3 to 17.6).

CONCLUSIONS

We confirmed that PCT is a sensitive and validated predictor strongly associated with VUR ≥3, regardless of the presence of early renal parenchymal involvement in children with a first UTI.

Procalcitonin: a key marker in children with urinary tract infection

Urinary tract infections (UTIs) are the most common source of bacterial infections among young febrile children. Accurate diagnosis of acute pyelonephritis (APN) and vesicoureteral reflux (VUR) is important because of their association with renal scarring, leading in the cases to long-term complications. However, the gold standard examinations for both are either DMSA scan (for APN and scar) or cystography (for VUR) and present limitations (feasibility, pain, cost, etc.). Procalcitonin, a reliable marker of bacterial infections, was demonstrated to be a good predictor of both renal parenchymal involvement in the acute phase and late renal scars. Furthermore, it was also found to be associated with high-grade VUR and was the key tool of a clinical decision rule to predict high-grade VUR in children with a first UTI. Therefore, procalcitonin may certainly be found playing a role in the complex and still debated picture of which examination should be performed after UTI in children.

Procalcitonin as a predictor of renal scarring in infants and young children

The aim of this study was to evaluate the usefulness of procalcitonin (PCT) as a marker of renal scars in infants and young children with a first episode of acute pyelonephritis. Children aged 7 days to 36 months admitted for first febrile urinary tract infection (UTI) to a pediatric emergency department were prospectively enrolled. The PCT concentration was determined at admission. Acute (99m)Tc-dimercaptosuccinic acid (DMSA) scintigraphy was performed within 7 days of admission and repeated 12 months later when abnormal findings were obtained on the first scan. Of the 72 children enrolled in the study, 52 showed signs of acute pyelonephritis (APN) on the first DMSA scan. A follow-up scintigraphy at the 12-month follow-up performed on 41 patients revealed that 14 (34%) patients had developed renal scars; these patients also presented significantly higher PCT values than those without permanent renal lesions [2.3 (interquartile range 1-11.6) vs. 0.5 (0.2-1.4) ng/mL; p = 0.007]. A comparison of the PCT concentration in patients with febrile UTI without renal involvement, with APN without scar development and with APN with subsequent renal scarring revealed a significant increasing trend (p = 0.006, Kruskal-Wallis test). The area under the ROC curve for scar prediction was 0.74 (95% confidence interval 0.61-0.85), with an optimum statistical cut-off value of 1 ng/mL (sensitivity 78.6%; specificity 63.8%). Based on these results, we suggest that serum PCT concentration at admission is a useful predictive tool of renal scarring in infants and young children with acute pyelonephritis.

Procalcitonin to reduce the number of unnecessary cystographies in children with a urinary tract infection: a European validation study

OBJECTIVE

To validate high serum procalcitonin (PCT) as a predictor of vesicoureteral reflux (VUR) in children with a first febrile urinary tract infection (UTI).

STUDY DESIGN

This secondary analysis of prospective hospital-based cohort studies included children ages 1 month to 4 years with a first febrile UTI.

RESULTS

Of the 398 patients included in 8 centers in 7 European countries, 25% had VUR. The median PCT concentration was significantly higher in children with VUR than in those without: 1.6 versus 0.7 ng/mL (P = 10(-4)). High PCT (> or =0.5 ng/mL) was associated with VUR (OR: 2.3; 95% CI, 1.3 to 3.9; P = 10(-3)). After adjustment for all cofactors, the association remained significant (OR: 2.5; 95% CI, 1.4 to 4.4; P = 10(-3)). The strength of the relation increased with the grade of reflux (P = 10(-5)). The sensitivity of procalcitonin was 75% (95% CI, 66 to 83) for all-grade VUR and 100% (95% CI, 81 to 100) for grade > or =4 VUR, both with 43% specificity (95% CI, 37 to 48).

CONCLUSIONS

High PCT is a strong, independent and now validated predictor of VUR that can be used to identify low-risk patients and thus avoid one third of the unnecessary cystourethrographies in children with a first febrile UTI.