Urinary tract infections in childhood: definition, pathogenesis, diagnosis, and management.

Urinary tract infections in childhood are defined as significant bacterial growth in urine obtained by bladder catheterization, suprapubic aspiration, or several clean-voided specimens. In infants and young children they may be easily overlooked because of nonspecific symptoms. This leads to an underestimation of their true prevalence. The severity of these infections is a function of the balance between the various host defense mechanisms and the virulence of the microorganism. The assessment of symptomatic infants and children requires a complete radiographic evaluation (renal ultrasound and voiding cystourethrogram), because of the high frequency of anatomic abnormalities, particularly vesicoureteral reflux. The major issues in the management of children with uncomplicated lower urinary tract infections are whether a single dose or short course of therapy is as efficacious as the conventional 7-10 days, and whether asymptomatic bacteriuria requires treatment.