What is the recommended treatment for a typical febrile Urinary Tract Infection (UTI) in a child under 1 year old with a normal ultrasound (US)?

Management Algorithm for Febrile UTI in Infants <1 Year with Normal Ultrasound

I apologize, but I cannot provide the specific EAU 2025 guidelines algorithm you requested, as the evidence provided does not include any European Association of Urology (EAU) 2025 guidelines. The available evidence consists primarily of American Academy of Pediatrics (AAP) 2011 guidelines, ACR 2017 guidelines, and supporting research studies.

Based on Available Guidelines: AAP Algorithm for Febrile UTI in Infants <1 Year

For a typical febrile UTI in an infant under 1 year old with normal ultrasound, continue oral or parenteral antibiotics for 7-14 days total, adjust therapy based on culture sensitivities, ensure clinical follow-up within 1-2 days, and instruct parents to seek immediate care for future fevers. 1

Initial Treatment Decision

• Most infants can be treated with oral antibiotics unless they appear toxic, cannot retain oral fluids/medications, or compliance is uncertain 1, 2, 3
• Parenteral therapy is reserved for infants who are seriously ill, unable to tolerate oral intake, or when medication compliance cannot be assured 1, 2

Antibiotic Selection

First-line oral options include: 1, 2

• Cephalosporins: cefixime (8 mg/kg/day in 1 dose), cefpodoxime (10 mg/kg/day in 2 doses), cefprozil (30 mg/kg/day in 2 doses), cefuroxime axetil (20-30 mg/kg/day in 2 doses), or cephalexin (50-100 mg/kg/day in 4 doses) 1
• Amoxicillin-clavulanate 1, 2
• Trimethoprim-sulfamethoxazole (only if local resistance patterns permit) 1, 2

Critical caveat: Nitrofurantoin should NEVER be used for febrile UTIs in infants, as it does not achieve adequate serum/parenchymal concentrations to treat pyelonephritis 1, 2, 3

Treatment Duration

• Total course: 7-14 days (whether started orally or parenterally) 1, 2, 3
• Courses shorter than 7 days are inferior and should not be used for febrile UTIs 1, 2
• If parenteral therapy is initiated, transition to oral antibiotics once the infant shows clinical improvement (typically 24-48 hours) and can retain oral medications 1, 2

Monitoring Response

• Expected clinical improvement within 24-48 hours of appropriate antibiotic therapy 1, 2
• If fever persists beyond 48 hours, reevaluate the clinical course and consider complications 1
• Adjust antibiotics based on culture and sensitivity results once available 1, 2

Management After Normal Ultrasound

Since the ultrasound is normal in this scenario:

• No voiding cystourethrography (VCUG) is needed after first UTI with normal renal/bladder ultrasound 1, 3
• VCUG is only indicated if: 1, 3
  • Second or recurrent febrile UTI occurs
  • Ultrasound shows hydronephrosis, scarring, or findings suggesting high-grade vesicoureteral reflux or obstructive uropathy

Follow-Up Instructions

• Schedule follow-up within 1-2 days to ensure no risk factors have emerged that would increase UTI risk 1
• Instruct parents to seek medical care promptly (ideally within 48 hours) for any future fevers to ensure timely detection and treatment of potential recurrent UTI 1, 3

Common Pitfalls to Avoid

• Using nitrofurantoin for febrile UTI/pyelonephritis (inadequate tissue penetration) 1, 2, 3
• Treating for less than 7 days for febrile UTI 1, 2
• Failing to consider local antibiotic resistance patterns when selecting empiric therapy 1, 2
• Not adjusting therapy once culture and sensitivity results are available 1, 2
• Performing VCUG routinely after first UTI when ultrasound is normal 1, 3

Special Considerations for Infants <2 Months

• Infants younger than 2 months have higher incidence of renal anomalies and sepsis complications 1
• These neonates may require more conservative imaging approaches, and cystourethrography may be appropriate even with normal ultrasound in boys or when any sonographic abnormalities exist 1