Urinary tract infection (UTI) is common in children, especially in young girls. UTI is present in about 5 percent of febrile infants and 2 percent of febrile children younger than 5 years of age. Infection confined to the lower urinary tract (cystitis) can recur, but it is generally not associated with long-term complications. However, infections of the upper urinary tract (pyelonephritis) can cause permanent scarring and renal damage. Hoberman and Wald describe the defining characteristics of both types of infection, along with the recommended management for each.

Escherichia coli is the causative organism in approximately 85 percent of infants and young children with UTI. Other pathogens include gram-negative bacteria such as Proteus species, Klebsiella pneumoniae and Pseudomonas aeruginosa. Gram-positive organisms, which are rarely involved in routine pediatric UTIs, include enterococci, staphylococci and group B streptococci.

Cystitis is characterized by dysuria, urgency, frequency and pain in the lower abdomen. Fever is less common. Oral antibiotics, including trimethoprim-sulfamethoxazole (TMP-SMX), amoxicillin-clavulanate and second-and third-generation cephalosporins, are usually effective. However, E. coli is becoming increasingly resistant to amoxicillin and TMP-SMX in some parts of the United States. The optimal duration of therapy is normally seven days, although shorter courses and single-dose regimens have demonstrated moderate but variable success.

More than 60 percent of young febrile patients with UTI have evidence of pyelonephritis. Febrile infants with UTI who are younger than one year of age generally require hospitalization and initial treatment with intravenous antibiotics until afebrile, followed by oral therapy for 10 to 14 days. Appropriate intravenous agents include cefotaxime, ceftriaxone, cefuroxime, ampicillin-sulbactam and gentamicin. Oral therapy depends on bacterial isolation and sensitivity. Recent studies question the need for long courses of intravenous cefotaxime when a short course of intravenous cefixime followed by oral therapy yields comparable results. The selection of appropriate treatment requires review of local antimicrobial resistance patterns and compliant caretakers who understand the seriousness of the infection, the need for exact antibiotic dosing and the importance of maintaining close contact with the treating physician. Oral antibiotics are sufficient for use in older children who present with high fever, abdominal or flank pain, and costovertebral angle tenderness if they do not appear to be toxic. Suitable medication choices include cefixime, other extended-spectrum cephalosporins (second- or third-generation), amoxicillin-clavulanate, TMP-SMX and, occasionally, quinolones.

Other important therapeutic considerations include reducing urinary stasis by encouraging liberal fluid intake and frequent voiding. Children also should be evaluated for constipation, which can compress the urethra or the bladder neck. Young children experiencing their first or second UTI should remain on oral prophylactic therapy until they undergo a voiding cystourethrogram. This test can be done safely as soon as the urine is sterile. Children with recurrent UTIs (more than three within one year) may require prophylactic therapy for six to 12 months to reduce morbidity.

The authors conclude that treatment of UTI with oral antibiotics is usually effective, even in younger children with pyelonephritis. Cefixime is a useful empiric choice. Children who appear toxic or who cannot tolerate oral medication should be hospitalized for initial intravenous therapy. Radiographic studies can be performed before completion of antibiotic therapy. Caretakers should be educated about the risk of recurrence and advised when to seek medical attention.