Urinary Tract Infection (Pediatric)

Definition

Pediatric urinary tract infection (UTI) is an infection of the urinary tract, including the bladder and kidneys, caused by bacteria, leading to dysuria, fever, and potential renal involvement.

Epidemiology

• Incidence higher in girls than boys after infancy
• 1–2% of girls and 0.5% of boys develop UTI annually in childhood
• More common in uncircumcised male infants
• Peak incidence in infancy and early childhood
• Recurrent UTIs occur in 5–10% of children after first episode

Etiology

• Bacterial: Escherichia coli (most common), Klebsiella, Proteus, Enterococcus
• Anatomic abnormalities: vesicoureteral reflux, posterior urethral valves
• Functional factors: constipation, dysfunctional voiding
• Poor hygiene, improper wiping, or sexual abuse in older children
• Immune deficiencies or chronic illnesses increase susceptibility

Pathophysiology

• Bacteria ascend from the urethra to bladder (cystitis) or kidneys (pyelonephritis)
• Adherence to uroepithelium via pili or fimbriae promotes colonization
• Host immune response causes inflammation, leading to dysuria, frequency, and hematuria
• Vesicoureteral reflux facilitates renal involvement
• Renal scarring can result from recurrent or severe infections
• Chronic infection may impair renal function and growth