Paediatric Recurrent Urinary Tract Infections

See also nocturnal enuresis, vulvitis & vulvovaginitis, and constipation in childhood (bowel and bladder dysfunction overlap).

UTIs affect up to 8.4% of girls and 1.7% of boys in their first 6 years; up to 30% recur within 6–12 months. 3–15% show renal scarring within 1–2 years of a first UTI, though the risk of progressing to chronic kidney disease is low. A UTI can be the first sign of an underlying urinary tract anomaly in up to a third of children.

Definitions

• UTI diagnosis requires both: urinalysis suggesting pyuria/ bacteriuria, and a culture with ≥50,000 CFU/mL of a uropathogen.
• Recurrent UTI (rUTI): ≥2 episodes of pyelonephritis; or 1 pyelonephritis + 1 cystitis episode; or ≥3 cystitis episodes.

Escherichia coli causes >75% of cases; others include Proteus, Klebsiella, Enterobacter, Enterococcus, Citrobacter, Staphylococcus aureus, and (less commonly) fungal or viral pathogens.

Differential diagnosis

Condition	Distinguishing features
Vaginitis	Discharge, odour, pruritus — no frequency/urgency
Vulvovaginitis	Can cause dysuria; may coexist with true UTI
Urethritis	Pyuria on urinalysis but no bacteria
Urge syndrome	Frequency, urgency, daytime wetting, enuresis
Painful bladder syndrome	Dysuria, frequency, urgency, no evidence of infection
Prostatitis	Tender prostate, pain on ejaculation
Sepsis/bacteraemia	Fever, malaise, anorexia, lethargy — mimics UTI symptoms in infants

A febrile infant <3 months should be managed per local sepsis/fever protocols — sometimes on clinical suspicion alone, without waiting for urine culture confirmation.

Specimen collection

Method	Best for	Key point
Clean catch/midstream	Continent/older children; first-line non-invasive option in infants with good parental cooperation	Non-invasive, minimal contamination, but relies on cooperation
Urethral catheterisation	Infants/pre-continent children unable to give a clean catch, or in urinary retention	Aseptic technique essential — risk of introducing uropathogens
Suprapubic aspiration	Infants, especially uncircumcised boys with non-retractile foreskin or girls with labial adhesions	Preferred aseptic method but invasive; needs a full bladder (>20 mL) ± light sedation

Risk factors for recurrence

Virulence	Concurrent illness	Anatomical (urine stasis)	Functional	Behavioural
Resistant organisms; incomplete prior treatment; immunosuppression; indwelling catheter colonisation	Gastroenteritis; dehydration (reduced voiding); vaginitis/vulvovaginitis; genital candidiasis; concurrent bacteraemia	Vesicoureteric reflux (up to 40% of children with a UTI); posterior urethral valves; phimosis; other obstructive uropathy (incl. urolithiasis); congenital renal/ureteric anomalies	Bowel/bladder dysfunction incl. constipation; other neurogenic bladder causes	Sexual activity (older patients); encopresis; poor perineal hygiene

Management

• Acute: choose antibiotics based on local sensitivities/guidelines and prior culture results; oral vs parenteral depends on age, urosepsis risk, ability to tolerate oral therapy, and vomiting/diarrhoea. Consider imaging and renal function monitoring, especially with recurrence.
• Refer children <6 months, those with sepsis/shock, or anyone needing care beyond local service capacity — to a paediatrician, paediatric urologist, or urology service as locally available.

Prevention

• Hygiene: correct perineal wiping technique (front-to-back), proper glans/foreskin care in uncircumcised boys, avoiding bubble baths (mucosal irritation mimics UTI symptoms).
• Non-antibiotic measures: probiotics and cranberry products have limited/conflicting evidence — not routinely recommended.
• Continuous antibiotic prophylaxis (CAP): no evidence supports starting this from the index UTI. Given resistance risk, involve a paediatric specialist in any decision to start long-term prophylaxis; adverse effects occur in 8–10% (mostly mild — nausea, vomiting, skin reactions). Reserve for high-risk children — those with both VUR and bowel/ bladder dysfunction are at highest risk and may benefit most. Common agents: trimethoprim ± sulfamethoxazole, or cefalexin, all dosed once nightly — each needs specific monitoring (FBE, folate, potassium, or renal function depending on agent) and has its own contraindications.
• Identify and manage VUR and bowel/bladder dysfunction specifically where present, as the two most important modifiable risk groups.