Usefulness of analytical parameters in the management of paediatric patients with suspicion of acute pyelonephritis. Is procalcitonin reliable?

OBJECTIVE

To investigate the usefulness of procalcitonin (PCT) and other analytical parameters (white blood cell count [WBC], C-reactive protein [CRP]) as markers of acute renal damage in children after a first febrile or afebrile urinary tract infection (UTI).

METHODS

A retrospective study was conducted on children with a first episode of UTI admitted between January 2009 to December 2011, and in whom serum PCT, CRP and white blood cell count were measured, as well as assessing the acute renal damage with renal scintigraphy with ^99mTc-DMSA (DMSA) within the first 72h after referral. A descriptive study was performed and ROC curves were plotted, with optimal cut-off points calculated for each parameter.

RESULTS

The 101 enrolled patients were divided into two groups according to DMSA scintigraphy results, with 64 patients being classified with acute pyelonephritis (APN), and 37 with UTI. The mean WBC, CRP and PCT values were significantly higher in patients with APN with respect to normal acute DMSA. The area under the ROC curve was 0.862 for PCR, 0.774 for WBC, and 0.731 for PCT. The optimum statistical cut-off value for PCT was 0.285ng/ml (sensitivity 71.4% and specificity 75%).

CONCLUSION

Although the mean levels of fever, WBC, CRP, and PCT were significantly increased in patients with APN than in those who had UTI, the sensitivity and specificity of these analytical parameters are unable to predict the existence of acute renal damage, making the contribution by renal DMSA scintigraphy essential.

[Renal scarring in children under 36 months hospitalised for acute pyelonephritis]

INTRODUCTION

Acute pyelonephritis (APN) is one of the most common causes of serious bacterial infection in infants. Renal scarring is the most prevalent long-term complication.

OBJECTIVES

To review the incidence of renal scarring within 6 months after an episode of APN in children under 36 months and its relationship with imaging studies, clinical settings, and bacteriology.

METHOD

A retrospective study of previously healthy patients aged one to 36 months, admitted for a first episode of APN, with a minimum follow-up of 6 months. Demographic and clinical variables were collected along with bacteriology, renal and bladder ultrasound scan, voiding cystourethrography, DMSA-scintigraphy, and re-infection events.

RESULTS

A total of 125 patients were included in the study, of which 60% were male, the large majority (92%) febrile, and due to E. coli (74.6%). There was a history of prenatal ultrasound scan changes in 15.4%. Ultrasound scan found dilation of the urinary tract in 22.1%. Voiding cystourethrography was performed on 70 patients: 54.3% no abnormalities, 12.8% vesicoureteral reflux (VUR) grade i-iii, and 32.9% iv-v grade VUR. Six patients had iv-v grade VUR with a normal ultrasound scan. Adherence to DMSA-scintigraphy at 6 months was only 61% of that indicated. Renal scarring was found in 44.3% of those in which it was performed (60 cases).

CONCLUSIONS

Almost half (44%) DMSA-scintigraphy in children aged one to 36 months hospitalised for APN show renal scarring at 6 months, which was found to be associated with the re-infection events and the iv-v grade VUR. There was no relationship between scarring and the bacteriology or the elevations of inflammatory biochemical markers.