Treatment of Urinary Tract Infections in Children
For children with confirmed UTI, initiate oral antibiotics for 7-14 days (10 days most common) using first-line agents such as amoxicillin-clavulanate, cephalosporins (cefixime, cephalexin), or trimethoprim-sulfamethoxazole if local resistance is <10%, reserving parenteral therapy only for toxic-appearing children, those unable to retain oral intake, or infants <3 months of age. 1, 2
Immediate Diagnostic Requirements Before Treatment
Obtain urine by catheterization or suprapubic aspiration in non-toilet-trained children—never use bag collection for culture as it has an 85% false-positive rate. 1, 2 For toilet-trained children, collect midstream clean-catch urine after cleaning external genitalia. 1, 3
- Diagnosis requires both pyuria (≥10 WBC/mm³ or positive leukocyte esterase) AND ≥50,000 CFU/mL of a single uropathogen on culture. 1, 2
- Always obtain culture before starting antibiotics—this is your only opportunity for definitive diagnosis and sensitivity testing. 1, 2
Treatment Algorithm by Age and Clinical Presentation
Neonates (<28 days old)
- Hospitalize immediately and initiate parenteral therapy with ampicillin plus aminoglycoside OR third-generation cephalosporin (ceftriaxone 50 mg/kg IV/IM every 24 hours). 1
- Complete 14 days total therapy. 1
Infants 29 days to 2 months
- Use ceftriaxone 50 mg/kg IV/IM every 24 hours as standard empirical therapy. 1
- For well-appearing, stable infants feeding well, oral cephalexin (50-100 mg/kg/day in 4 doses) or cefixime (8 mg/kg/day in 1 dose) are acceptable alternatives. 1
- Consider voiding cystourethrography (VCUG) in boys due to higher prevalence of vesicoureteral reflux and to exclude posterior urethral valves. 4, 1
Children 2 months to 6 years
- Start oral antibiotics immediately if febrile UTI is suspected—early treatment within 48 hours reduces renal scarring risk by >50%. 1, 2
- First-line oral options: 1, 2
- Use parenteral ceftriaxone 50 mg/kg IV/IM every 24 hours if child appears toxic, cannot retain oral intake, has uncertain compliance, or fever persists >48 hours on appropriate oral therapy. 1, 2
Children >6 years
- Routine imaging not needed as vesicoureteral reflux is less common. 4
- Use same oral antibiotic options as younger children for 7-14 days. 1, 2
Treatment Duration by Infection Type
For febrile UTI/pyelonephritis: 7-14 days (10 days most commonly supported), with oral and parenteral routes equally efficacious when child can tolerate oral medications. 1, 2
- For uncomplicated cystitis in children >2 years: shorter courses of 3-5 days appear comparable to 7-14 days. 1
- Never treat febrile UTI for less than 7 days—shorter courses are definitively inferior. 1
Critical Antibiotics to AVOID
- Never use nitrofurantoin for febrile UTI/pyelonephritis—it does not achieve adequate serum/parenchymal concentrations to treat kidney infection. 1, 6
- Avoid fluoroquinolones in children due to musculoskeletal safety concerns; reserve only for severe infections where benefits outweigh risks. 1
Imaging Strategy
After First Febrile UTI in Children <2 Years
- Obtain renal and bladder ultrasound (RBUS) to detect anatomic abnormalities—this is usually appropriate (rating 9/9). 4, 1, 2
- Perform ultrasound with patient well-hydrated and bladder distended. 1
Voiding Cystourethrography (VCUG) Indications
- NOT routinely recommended after first UTI. 1, 2
- Perform VCUG if: 1, 2
- RBUS shows hydronephrosis, scarring, or findings suggesting high-grade vesicoureteral reflux or obstructive uropathy
- Second febrile UTI occurs
- Fever persists >48 hours on appropriate therapy
- Male infant <2 months (consider due to higher VUR prevalence)
After Age 6 Years
- No routine imaging needed for first uncomplicated UTI. 4
Follow-Up Protocol
Immediate (1-2 Days)
- Clinical reassessment within 1-2 days is critical to confirm fever resolution and response to antibiotics. 1
- If fever persists beyond 48 hours of appropriate therapy, reevaluate diagnosis and consider antibiotic resistance or anatomic abnormalities. 1
Long-Term
- No routine scheduled visits after successful treatment of first uncomplicated UTI. 1, 2
- Instruct parents to seek prompt medical evaluation (within 48 hours) for any future febrile illness to detect recurrent UTI early. 1, 2
Antibiotic Prophylaxis Considerations
- NOT routinely recommended after first UTI. 1
- Consider selectively only in high-risk patients: recurrent febrile UTIs, high-grade vesicoureteral reflux (grades IV-V), or bowel/bladder dysfunction with VUR. 1
- The RIVUR trial showed prophylaxis reduced recurrent UTI by ~50% in children with VUR grades I-IV but did not reduce renal scarring. 1
When to Refer to Pediatric Nephrology/Urology
- Recurrent febrile UTIs (≥2 episodes) 1
- Abnormal RBUS showing hydronephrosis, scarring, or structural abnormalities 1
- Poor response to appropriate antibiotics within 48 hours 1
- Non-E. coli organisms or suspected complicated infection 1
Common Pitfalls to Avoid
- Delaying treatment—early antimicrobial therapy within 48 hours decreases renal damage risk by >50%. 1, 2
- Using bag collection for urine culture (85% false-positive rate). 1
- Treating for <7 days for febrile UTI. 1
- Using nitrofurantoin for any febrile/systemic UTI. 1, 6
- Failing to adjust therapy based on culture and sensitivity results. 1, 2
- Not considering local antibiotic resistance patterns when selecting empiric therapy. 1, 2
- Treating asymptomatic bacteriuria (no treatment indicated). 1