URINARY TRACT INFECTIONS IN CHILDREN: EPIDEMIOLOGY, CLINICAL FEATURES, AND DIAGNOSIS

Abstract

Objectives. To synthesize current evidence on the epidemiology, age-specific clinical manifestations, microbiological etiology, risk factors, and conventional and emerging diagnostic strategies for urinary tract infections (UTIs) in children, with particular attention to antimicrobial resistance (AMR) and renal risk.

Methods. A narrative review was conducted using a structured search of PubMed, Scopus, and Web of Science for publications issued between 1 January 2020 and 3 August 2026. Pediatric guidelines and consensus documents, systematic reviews and meta-analyses, randomized controlled trials, diagnostic accuracy studies, and population-based, cohort, and other observational studies were considered.

Results. UTIs affect approximately 8% of girls and 2% of boys during the first decade of life, and recurrence occurs in about 30% of affected children. Boys predominate during early infancy, whereas girls are more frequently affected after the first year of life. Escherichia coli causes approximately 80% of pediatric UTIs, although increasing multidrug resistance and extended-spectrum beta-lactamase production complicate empirical treatment. Clinical manifestations are predominantly nonspecific in infants and become more localized with age. Recurrent infection, congenital urinary tract anomalies, vesicoureteral reflux, and bladder-bowel dysfunction increase the likelihood of renal involvement. Urinalysis and urine culture remain the diagnostic foundation, with specimen quality being essential for reliable interpretation. Biomarkers and molecular assays may accelerate pathogen and resistance detection, but their routine pediatric use remains limited by cost, validation requirements, and uncertain clinical specificity.

Conclusions. An age-adapted diagnostic approach is essential in children with suspected urinary tract infection. Early recognition, reliable urine sampling, culture-based confirmation, awareness of local resistance patterns, and selective use of imaging help identify children at risk of recurrence or renal involvement. Emerging molecular tools are promising adjuncts but should complement rather than routinely replace conventional microbiological methods.