Pediatric Urinary Tract Infection

Key considerations: Pyelonephritis (upper UTI), Urosepsis, Renal abscess

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history: Fever duration and height; Irritability, fussiness, poor feeding (infants); Dysuria, frequency, urgency (verbal children); Foul-smelling urine; Previous UTIs; Family history of VUR or renal anomalies; Circumcision status (uncircumcised males: higher UTI risk); exam: Fever assessment; Abdominal and flank tenderness; Suprapubic tenderness; External genitalia exam; Costovertebral angle tenderness (older children); labs: Urinalysis: leukocyte esterase, nitrites, WBC; Urine culture: CATHETERIZED specimen <2 years (bag specimens have high contamination rate); CBC, CRP, procalcitonin if pyelonephritis suspected; Blood culture if <2 months or septic-appearing; BMP/Cr if concern for renal impairment; imaging: Renal/bladder ultrasound: first febrile UTI in child <2 years or any age if recurrent; VCUG: only if ultrasound abnormal, recurrent febrile UTIs, or atypical organism; DMSA scan: gold standard for pyelonephritis and renal scarring (usually outpatient); bedside: Temperature; Bladder catheterization for clean specimen <2 years

immediate: Antipyretics for comfort; IV antibiotics if septic-appearing or unable to tolerate PO; general: AAP 2011: UTI diagnosis requires BOTH positive UA AND positive culture (≥50,000 CFU/mL catheterized); Bag specimens are screening only — positive bag UA needs catheterized confirmation before treating; specific: diagnosis: Cystitis (lower UTI); steps: Oral antibiotics: cephalexin 25-50mg/kg/day divided BID-QID x7 days; Or TMP-SMX 6-12mg/kg/day of TMP divided BID x7 days (if susceptible); Adequate hydration; Follow-up urine culture NOT routinely needed if clinical improvement; diagnosis: Pyelonephritis; steps: Ceftriaxone 50mg/kg IV/IM x1 then transition to oral (outpatient if well-appearing, >2 months); Or admission for IV ceftriaxone if toxic, <2 months, unable to tolerate PO; Total treatment course 7-14 days; Renal ultrasound during admission or within 2 weeks; diagnosis: Neonatal UTI; steps: Full sepsis workup including blood and CSF cultures; IV ampicillin + gentamicin (or ceftriaxone if >28 days); Admission for IV antibiotics; Renal ultrasound and likely VCUG

admit: Neonates and infants <2 months with UTI; Toxic or septic-appearing child; Unable to tolerate oral antibiotics; Known urologic abnormalities with pyelonephritis; Failed outpatient management; discharge: Well-appearing child >2 months with uncomplicated UTI; Tolerating oral antibiotics; Reliable caregivers and follow-up; Pyelonephritis >2 months with initial IV/IM dose and oral transition if well-appearing; consults: Pediatric urology if structural abnormality found on imaging; Nephrology if recurrent UTIs or VUR; Infectious disease if resistant organisms

AAP requires BOTH positive UA AND positive culture for UTI diagnosis — do not treat a positive UA alone without culture confirmation
Bag urine specimens have up to 85% false-positive rate — always catheterize for culture in non-toilet-trained children
Uncircumcised males <1 year have 10x higher UTI risk than circumcised males
Fever without source in infant 2-24 months: UTI prevalence is ~5% — always send UA and culture

AAP UTI Guidelines 2011 (reaffirmed 2016), NICE UTI in Children Guidelines. Last reviewed: 2024-11-01