What is the recommended treatment for a child with a urinary tract infection (UTI)?

Treatment of Urinary Tract Infections in Children

For most children with UTI, initiate oral antibiotics for 7-14 days, reserving parenteral therapy only for toxic-appearing children, those unable to retain oral intake, or infants <2-3 months of age. 1, 2

Initial Antibiotic Selection

First-line oral options include:

• Amoxicillin-clavulanate (20-40 mg/kg/day divided into 3 doses) 2
• Cephalosporins (cefixime, cephalexin, cefpodoxime) 1, 3
• Trimethoprim-sulfamethoxazole (40 mg/kg sulfamethoxazole + 8 mg/kg trimethoprim per 24 hours in 2 divided doses) ONLY if local E. coli resistance is <10% for pyelonephritis or <20% for lower UTI 1, 4

For parenteral therapy (toxic appearance, unable to retain oral medications, age <2-3 months):

• Ceftriaxone 50-75 mg/kg IV/IM every 24 hours 1, 2
• For neonates <28 days: ampicillin + aminoglycoside or third-generation cephalosporin for 14 days total 1, 5

Treatment Duration by Clinical Presentation

Febrile UTI/Pyelonephritis:

• 7-14 days total (10 days most commonly recommended) 1, 2
• Shorter courses of 1-3 days are inferior and should not be used 1, 3

Non-febrile UTI/Cystitis (children >2 years):

• 7-10 days for moderate-to-severe symptoms 1
• Shorter courses (3-5 days) may be comparable to longer courses, though evidence is moderate strength 1

Critical Diagnostic Requirements Before Treatment

Obtain urine culture BEFORE starting antibiotics via: 1, 2

• Catheterization or suprapubic aspiration for non-toilet-trained children 1, 2
• Midstream clean-catch for toilet-trained children 1
• Never use bag specimens for culture—false-positive rates reach 70-85% 1, 2

Diagnosis requires both: 1

• Pyuria (≥5 WBC/HPF on centrifuged specimen OR positive leukocyte esterase) AND
• ≥50,000 CFU/mL of a single uropathogen on culture

Adjusting Therapy

Once culture results are available: 1, 2

• Adjust antibiotics based on sensitivity testing
• Consider local antibiotic resistance patterns when selecting empiric therapy
• E. coli resistance to trimethoprim-sulfamethoxazole ranges from 19-63% in some regions 3

Imaging Recommendations

For children <2 years with first febrile UTI: 1, 2

• Obtain renal and bladder ultrasound (RBUS) to detect anatomic abnormalities
• Perform after initiating treatment, with patient well-hydrated and bladder distended

For children ≥2 years with first uncomplicated febrile UTI: 3

• Routine imaging is NOT indicated if good response to treatment within 48 hours
• Consider imaging only if atypical features present (see below)

Voiding cystourethrography (VCUG): 1, 2

• NOT recommended routinely after first UTI
• Perform after second febrile UTI
• Consider if RBUS shows hydronephrosis, scarring, or findings suggesting high-grade vesicoureteral reflux or obstruction

Imaging IS indicated if: 3

• Poor response to antibiotics within 48 hours
• Septic or seriously ill appearance
• Poor urine stream or elevated creatinine
• Non-E. coli organism
• Recurrent UTI

Follow-Up Strategy

Short-term (1-2 days): 1

• Clinical reassessment to confirm fever resolution and response to antibiotics
• If fever persists beyond 48 hours, reevaluate diagnosis and consider antibiotic resistance or anatomic abnormalities

Long-term: 1, 2

• No routine scheduled visits after successful treatment of first uncomplicated UTI
• Instruct parents to seek prompt medical evaluation (within 48 hours) for any future febrile illness
• Obtain urine specimen at onset of subsequent fevers

Critical Pitfalls to Avoid

Do NOT: 1, 2

• Use nitrofurantoin for febrile UTI/pyelonephritis—it does not achieve adequate serum/parenchymal concentrations
• Treat for less than 7 days for febrile UTI—shorter courses are inferior
• Fail to obtain urine culture before starting antibiotics
• Delay treatment—early treatment (within 48 hours) reduces renal scarring risk by >50%
• Use fluoroquinolones in children except for severe infections where benefits outweigh musculoskeletal safety concerns
• Treat asymptomatic bacteriuria—this may promote resistant organisms
• Rely on bag specimens for culture diagnosis

Antibiotic Prophylaxis

Routine prophylaxis is NOT recommended for: 1

• Children after first UTI
• Children with vesicoureteral reflux grades I-IV (RIVUR trial showed no reduction in renal scarring despite 50% reduction in recurrent UTI)

Consider prophylaxis selectively only for: 1

• High-risk patients with recurrent febrile UTI
• High-grade vesicoureteral reflux with benefits weighed against resistance risk

Long-Term Complications

Renal scarring occurs in approximately 15% of children after first UTI and can lead to: 1, 2

• Hypertension (5% of cases)
• Chronic kidney disease (3.5% of end-stage renal disease cases)
• Complications in future pregnancies

Early treatment within 48 hours of fever onset reduces renal scarring risk by more than 50%. 1, 2