Urinary Tract Infection (UTI) – Children

🔍 When to Suspect

A child with urinary symptoms or unexplained fever; symptoms are often non-specific in infants <3 months (e.g., fever, vomiting, poor feeding)

From the full topic in The Ocean Library: Urinary Tract Infection (UTI) – Children

🧭 When to suspect

Suspect a urinary tract infection (UTI) in any child with urinary symptoms or an unexplained fever – it is one of the commonest serious bacterial infections of childhood, and it is easily missed because the presentation is so age-dependent. In infants under 3 months, the signs are non-specific: fever, vomiting, poor feeding, lethargy, irritability or prolonged jaundice. In children over 3 months, look for dysuria, frequency, urgency, abdominal or loin pain, new daytime wetting, and cloudy or malodorous urine. E. coli causes the great majority of cases.

Two skills matter most. First, an age rule: any baby under 3 months with a suspected UTI needs immediate paediatric referral, with urine sent for urgent microscopy and culture – never a dipstick rule-out. Second, separate lower UTI (cystitis) from acute upper UTI (pyelonephritis), because it changes both the antibiotic course length and the threshold for referral. NICE defines an upper UTI as bacteriuria with a fever of 38°C or higher, or bacteriuria with a fever below 38°C plus loin pain or tenderness.

Lower UTI (cystitis)	Upper UTI (acute pyelonephritis)
• Bacteriuria with no systemic features.	• Bacteriuria plus fever ≥38°C, or fever <38°C with loin pain/tenderness.
• Dysuria, frequency, urgency, suprapubic or abdominal pain, new daytime wetting, cloudy or offensive urine.	• Systemically unwell – high fever, rigors, vomiting, loin pain.
• Oral antibiotics for 3 days.	• Antibiotics for 7–10 days; consider paediatric referral.

Source: NICE NG224 · NICE NG109 · NICE NG111

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