Paediatrics: Urinary tract infection

Urinary tract infection

Up to 3% of girls and 1% of boys suffer from UTI during childhood. A UTI may be defined in terms of the presence of symptoms (dysuria, fre-quency, loin pain) plus the detection of a significant culture of organisms in the urine:

•   Any growth on culture of suprapubic aspirate.

•   >10⁵ Organisms/mL in pure growth from a carefully collected urine sample (midstream urine, clean catch urine, or bag urine). Ideally 2 consecutive growths of the same organism with identical sensitivities, but this is not always practical.

Note: Bacteriuria in the absence of symptoms does not necessarily need treatment, but needs to be considered in the clinical context (e.g. previous UTI, predisposing urinary tract abnormalities).

Guidance on the investigation, treatment and management of UTIs have been published.¹

Clinical features

Presentation varies; symptoms in infants may be non-specific:

•   vomiting/diarrhoea;

•   poor feeding/failure to thrive;

•   prolonged neonatal jaundice.

Examination

•   Height and weight: plot on growth chart.

·  BP.

•   Examination for abdominal masses.

•   Examine genitalia and spine for congenital abnormalities.

•   Examine lower limbs for evidence of neuropathic bladder.

Diagnosis

Try to distinguish between upper (fever, vomiting, loin pain) vs. lower uri-nary tract symptoms (dysuria, frequency, mild abdominal pain, enuresis). Differentiation is often not possible in the younger child.

•   UTI is a major cause of sepsis in a young infant.

•   Ask about urinary stream in boys and family history of vesicoureteric reflux (VUR) or other urinary tract abnormality.

•   Dipstick test in the urine. ‘Leucocytes’ and ‘nitrites’ strongly suggests UTI. Urine should be sent for microscopy, culture, and sensitivity.

Acute treatment

Antibiotics should be started after urine collection (see Table 11.2).

Chose antibiotic from:

• Trimethoprim 4mg/kg twice daily.

• Cefradine 25mg/kg twice daily.

• Cefalexin 25mg/kg twice daily.

• Co-amoxiclav 125/31 (1–6yrs), 5mL 3 times a day.

• Co-amoxiclav 250/62 (7–12yrs) 5mL 3 times a day.

• IV cefuroxime 25mg/kg 8-hourly; or

• IV gentamicin 2.5mg/kg/dose 8-hourly.

A repeat urine culture should be obtained on completion of antibiotics.

Follow-up and investigations

All children presenting with UTI should be investigated for any renal scar-ring and predisposing urinary tract abnormalities. Pyelonephritis or recur-rent pyrexial UTIs need more comprehensive investigation than those at low risk (single, uncomplicated UTI with lower tract symptoms). Oral an-tibiotic prophylaxis  may need to be started and continued until investigations are complete.

Recommended imaging tests (Tables 11.3–11.5)

UTI prevention

Predisposing factors to recurrent UTIs should be avoided:

•   Treat and prevent constipation.

•   Hygiene: clean perineum front to back.

•   Avoid nylon underwear and bubble baths.

·  Encourage fluid intake and regular toileting with double micturition.

Do not routinely use antibiotic prophylaxis after first-time UTI, but con-sider it after recurrent UTI.

Oral antibiotic prophylaxis (trimethoprim 2mg/kg at night or nitrofuran-toin 1mg/kg) is required if:

•   VUR.

•   Recurrent UTIs (more than 2–3 episodes)