INTRODUCTION: Distinguishing upper from lower urinary tract infections (UTI) has important clinical implications in children, especially in those younger than 2 years of age. The objective of this study was to test differences between upper and lower UTIs by using serum and urine biomarkers.
METHODS: Participants were 83 patients with UTI based on suggestive clinical symptoms and at least 1 positive urine culture. All had renal scintigraphy. Children with known concomitant diseases, any type of renal disorder, or a previous diagnosis of vesicoureteral reflux were excluded. Before the initiation of antibiotic treatment, blood was sampled for white blood cell (WBC) count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and procalcitonin (PCT). Urinary interleukin-6 (uIL-6) and macrophage migration inhibitory factor (MIF) were also measured. Data were analyzed using the Mann-Whitney or t test. Sensitivity and specificity were calculated for some variables in isolation and in combination.
RESULTS: There were 61 girls and 22 boys with mean (SD) age of 8.7 (3.4) months and 7.8 (4.5) months, respectively; 49 patients had acute pyelonephritis (APN) and 34 had lower UTI. The mean WBC counts were significantly higher in the group with APN than in the group with lower UTI (P < .01), as were CRP and ESR levels (P < .001). Significantly higher serum PCT, urinary IL-6, and MIF levels were detected in patients with APN when compared with patients with lower UTI (all with P < .001). For the prediction of APN, sensitivity and specificity levels were 95.9% and 88.2% for CRP, 87.8% and 91.2% for PCT, 71.4% and 94.1% for uIL-6, and 93.9% and 97.1% for urinary MIF. The sensitivity and specificity for CRP combined with other biomarkers were 93.9% and 91.2% (PCT with CRP), 95.9% and 91.2% (uMIF with CRP), and 85.7 % and 94.1% (uIL-6 with CRP), respectively.
CONCLUSION: Some biomarkers, used solely or in combination, help to differentiate between upper and lower UTI and may make more aggressive and invasive testing unnecessary in the future.
Ahmed J Al-Sayyad, Salah M EL-Morshedy, Ehab A abd Al Hamid, Nehad A Karam, A Basset A Imam, Rehab A Karam
Submitted April 10, 2011 - Accepted for Publication May 25, 2011
KEYWORDS: Urinary tract infection; Acute pyelonephritis; Biomarkers
CORRESPONDENCE: Ahmed Al-Sayyad MD, FRCSC, Assistant Professor and Consultant of Pediatric Urology, King Abdulaziz University, PO Box 1817 Jeddah 21441, Saudi Arabia ().
CITATION:UroToday Int J. 2011 Aug;4(4):art49. doi:10.3834/uij.1944-5784.2011.08.05.
ABBREVIATIONS AND ACRONYMS: APN, acute pyelonephritis; CRP, C-reactive protein; DMSA, dimercaptosuccinic acid; ELISA, enzymelinked immunosorbent assay; ESR, erythrocyte sedimentation rate; IL-6, interleukin-6; MIF, migration inhibitory factor; PCT, procalcitonin; RPI, renal parenchymal involvement; UTI, urinary tract infection; WBC, white blood cell.