Urinary Tract Infection (UTI) for 5th Grade

Epidemiology

• Approximately 3% of girls and 1% of boys have a UTI during their prepubertal years.
• The highest incidence of UTI is in the first year of life, with uncircumcised boys being at a 10-fold greater risk of developing a UTI compared to circumcised boys during this period.
• After 12 months of age, UTI in healthy children is usually seen in girls (short urethra predisposes girls to UTIs).

Etiology

• UTIs are caused primarily by colonic bacteria.
• Escherichia coli causes 54-67% of all UTIs, followed by Klebsiella spp. and Proteus spp., Enterococcus, and Pseudomonas.
• Other bacteria known to cause UTIs include Staphylococcus saprophyticus, group B streptococcus, and, less commonly, Staphylococcus aureus, Candida spp., and Salmonella spp.

Pathogenesis and Pathology

• Nearly all UTIs are ascending infections.
• Bacteria arise from the fecal flora, colonize the perineum, and enter the bladder via the urethra.
• In uncircumcised males, bacterial pathogens arise from the flora beneath the prepuce.
• Bacteria causing cystitis can ascend to the kidney to cause pyelonephritis.
• Rarely, renal infection occurs by hematogenous spread, as in endocarditis or in some bacteremia neonates.
• Children of any age with a febrile UTI can have acute pyelonephritis and subsequent renal scarring, but the risk is highest in those younger than 2 years of age.

Diagnosis

• UTIs may be suspected based on symptoms or findings on urinalysis, or both.
• Urinalysis (GUE) and urine culture are necessary for confirmation of diagnosis and appropriate therapy.
• Imaging studies (e.g., ultrasound of the bladder and kidney, VCUG, and technetium-99m dimercaptosuccinic acid (DMSA) scan) are used to identify anatomical abnormalities and detect hydronephrosis.

Treatment

• Acute cystitis should be treated promptly to prevent possible progression to pyelonephritis.
• A 3- to 5-day course of therapy with trimethoprim-sulfamethoxazole (TMP-SMX), nitrofurantoin, or amoxicillin is effective against many strains of E. coli.
• In acute febrile UTIs, a course of antibiotics for 7-14 days is required.
• Hospital admission and intravenous (IV) rehydration and IV antibiotic therapy are indicated for children who are dehydrated, vomiting, unable to drink fluids, or those with complicated infections or urosepsis.

Prevention

• Primary prevention is achieved by promoting good perineal hygiene and managing underlying risk factors for UTI, such as chronic constipation and daytime and nighttime urinary incontinence.
• Urologic conditions for recurrent UTIs that might benefit from long-term prophylaxis include neuropathic bladder, urinary stasis and obstruction, urinary calculi, and severe vesicoureteral reflux.
• Antimicrobial prophylaxis using trimethoprim or nitrofurantoin at 30% of the normal therapeutic dose once a day can be effective.

Vesico Ureteral Reflux

• Vesicoureteral reflux (VUR) is retrograde flow of urine from the bladder to the ureter or kidney.
• VUR is the most common anatomic abnormality found in infants and young children with febrile UTI.
• There is a genetic predisposition to primary VUR with an increased risk in children with affected parents or siblings.
• Secondary VUR may be present in children with other urinary tract anomalies.
• Clinical manifestations of VUR include febrile UTI, recurrent febrile UTI, and asymptomatic presentations.
• Diagnostic studies for VUR include renal ultrasound and voiding cystourethrogram (VCUG).
• Management options for a child with VUR include surveillance, medical therapy, and surgical intervention.