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

Abstract

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.

Keywords: (99m)Tc-DMSA; Infección del tracto urinario; Paediatrics; Pediatría; Pielonefritis; Procalcitonin; Procalcitonina; Pyelonephritis; Urinary tract infection.