Treatment of Pediatric Urinary Tract Infections
For most children with UTI, initiate oral antibiotics for 7-14 days (10 days most common), reserving parenteral therapy only for toxic-appearing children, those unable to retain oral medications, or infants under 28 days. 1
Initial Antibiotic Selection by Clinical Presentation
Febrile UTI/Pyelonephritis (First-Line Oral Options)
- Amoxicillin-clavulanate at 40-45 mg/kg/day divided every 12 hours is a reasonable first-line choice if local E. coli resistance rates are acceptable 1, 2
- Cephalosporins (cefixime 8 mg/kg/day in 1 dose, cephalexin 50-100 mg/kg/day in 4 doses, or cefpodoxime) are excellent alternatives 1, 2
- Trimethoprim-sulfamethoxazole (40 mg/kg sulfamethoxazole + 8 mg/kg trimethoprim per 24 hours divided every 12 hours) should only be used if local resistance rates are <10% 3, 1, 4
Non-Febrile UTI/Cystitis (First-Line Oral Options)
- Nitrofurantoin is the preferred agent for uncomplicated cystitis, as it spares more systemically active agents 3
- Cephalexin, amoxicillin-clavulanate, or TMP/SMX (if local resistance <20%) are acceptable alternatives 3, 1
Parenteral Therapy Indications
- Ceftriaxone 50 mg/kg IV/IM every 24 hours is the recommended empirical choice for children requiring parenteral therapy 3, 1
- Reserve parenteral therapy for: toxic appearance, inability to retain oral intake, uncertain compliance, or age <28 days 1, 2
- For neonates <28 days: use ampicillin + cefotaxime (or aminoglycoside) and complete 14 days total therapy 1, 5
Treatment Duration by Syndrome
Febrile UTI/Pyelonephritis
- 7-14 days total duration (10 days most commonly recommended) 3, 1, 2
- Courses shorter than 7 days are inferior and should be avoided 1, 6
- Transition from IV to oral therapy is appropriate once afebrile for 24 hours and clinically improved 1, 5
Non-Febrile UTI/Cystitis
- 7-10 days for moderate-to-severe symptoms 1
- 3-5 days may be adequate for uncomplicated cystitis in children >2 years, though evidence is not conclusive 1
Critical Medication Considerations
Never use nitrofurantoin for febrile UTI/pyelonephritis, as it does not achieve adequate serum or parenchymal concentrations to treat upper tract infections 1, 2
Age-Specific Treatment Algorithms
Neonates (<28 days)
- Hospitalize and initiate ampicillin + cefotaxime (or aminoglycoside) parenterally 1, 5
- Complete 14 days total therapy 1, 5
Infants (29 days to 3 months)
- If toxic-appearing: hospitalize, give ceftriaxone or gentamicin IV until afebrile 24 hours, then complete 14 days with oral antibiotics 5
- If well-appearing: may manage as outpatient with daily ceftriaxone or gentamicin until afebrile 24 hours, then complete 14 days oral 1, 5
Children (>3 months)
- Most can be treated entirely with oral antibiotics for 7-14 days 1, 2
- Parenteral therapy only if toxic-appearing or unable to tolerate oral medications 1, 2
Adjusting Therapy Based on Culture Results
- Always obtain urine culture before starting antibiotics via catheterization or suprapubic aspiration in non-toilet-trained children 1
- Adjust antibiotics based on culture and sensitivity results when available 3, 1
- Expect clinical improvement (defervescence) within 24-48 hours of appropriate therapy 1, 2
- If fever persists beyond 48 hours on appropriate antibiotics, reevaluate for antibiotic resistance or anatomic abnormalities 1
Imaging Recommendations
First Febrile UTI
- Obtain renal and bladder ultrasound (RBUS) for all children <2 years with first febrile UTI to detect anatomic abnormalities 1, 2
- RBUS is NOT routinely required for children >2 years with first uncomplicated UTI 1
Voiding Cystourethrography (VCUG)
- NOT recommended routinely after first UTI 1, 2
- Perform VCUG only if: RBUS shows hydronephrosis/scarring, after second febrile UTI, or fever persists >48 hours on appropriate therapy 1, 2
Antibiotic Prophylaxis
Continuous antibiotic prophylaxis is NOT recommended for children after first UTI, children with recurrent UTIs, children with VUR grades I-IV, children with isolated hydronephrosis, or children with neurogenic bladder 1, 7
- Prophylaxis may be considered selectively only in children with significant obstructive uropathies until surgical correction 7
- The RIVUR trial showed prophylaxis reduced recurrent UTI by 50% but did not reduce renal scarring 1
- Risk of antimicrobial resistance outweighs benefits in most cases 7
Follow-Up Strategy
Short-Term (1-2 Days)
- Clinical reassessment within 1-2 days to confirm response to antibiotics and fever resolution 1
- This early follow-up detects treatment failure before complications develop 1
Long-Term
- No routine scheduled visits after successful treatment of first uncomplicated UTI 1
- Instruct parents to seek prompt evaluation (within 48 hours) for any future febrile illness to detect recurrent UTIs early 1
Common Pitfalls to Avoid
- Do not use nitrofurantoin for febrile UTI/pyelonephritis - inadequate tissue penetration 1, 2
- Do not treat for less than 7 days for febrile UTI - shorter courses are inferior 1, 6
- Do not fail to obtain urine culture before starting antibiotics - this is the only opportunity for definitive diagnosis 1
- Do not use bag specimens for culture - 85% false-positive rate 1
- Do not treat asymptomatic bacteriuria - leads to antimicrobial resistance 2
- Do not ignore local antibiotic resistance patterns - select empiric therapy based on local data 3, 1
- Do not routinely order VCUG after first UTI - not indicated unless specific criteria met 1, 2
When to Refer to Pediatric Nephrology/Urology
- Recurrent febrile UTIs (≥2 episodes) 1
- Abnormal renal ultrasound 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