Site Home

Clinical Practice Guidelines

RCH > Medicine > General Medicine > Clinical Practice Guidelines

 

Urinary Tract Infection Guideline

Background

  • You must obtain a definitive diagnosis by culture of urine obtained in a sterile fashion (MSU, SPA, CSU - see below).
  • UTI cannot be diagnosed on symptoms alone, nor by culture of urine from a bag specimen.
  • Urinary dipstick testing is only a screening test for UTI. It has poor sensitivity and specificity (see below).
  • Finding a UTI in a sick child does not exclude another site of serious infection (eg meningitis). Remember that 2% of young children will have asymptomatic bacteruria and this may not be the cause of this acute presentation. Organisms may spread from urinary tract to elsewhere including meninges. Do not omit an LP in a sick child just because you have found a UTI.
  • Prior antibiotic therapy may lead to negative urine culture in patients with UTI. The laboratory will test for antibacterial activity in the urine.

Goto Top

Assessment

History

  • In infants and children, features are often non-specific (eg. fever, irritability, poor feeding and vomiting).
  • More specific features may include loin or abdominal pain, frequency and dysuria. These are often absent in younger patients.
  • Some children with urinary tract infections may look quite  well, while others may appear very unwell.

Examination

  • Is often normal other than the presence of fever. Loin or supra-pubic tenderness may be present.

Goto Top

Treatment

  • Any child who is unwell, and most children under 6 months, should be admitted for i.v. antibiotics. Include blood culture, electrolytes and consider an LP.
  • A shocked child will require fluid resuscitation.
  • Discuss children with known underlying urinary tract abnormalities with a consultant.

Gentamicin 7.5 mg/kg (240 mg) iv daily and benzylpenicillin 50 mg/kg (3g) iv 6 hourly for children over 1 month of age. Remember gentamicin levels.

If oral medication is appropriate:

  • Trimethoprim 4mg/kg (150mg max) BD (only tablets generally available)
    or
  • co-trimoxazole (200/40 mg in 5 ml) 0.5 ml/kg (20ml max) BD
    or
  • Cephalexin 15mg/kg (500mg max) TDS
  • All for 1 week

Check antibiotic sensitivities and adjust therapy in 24 to 48 hours.

Routine prophylaxis is no longer recommended.

Goto Top

Investigation

All children with first UTI

Renal ultrasound is usually performed in young children after first UTI, especially those under 4 years of age. The main purpose of ultrasound is to exclude urinary tract obstruction.

The following patients should have a renal ultrasound prior to discharge from RCH:

  • Admitted patients less than 6 months of age (especially boys).
  • Those who are particularly sick (needs consent of medical consultant)

All others (ie most cases) should have their ultrasound performed as an outpatient. Usually the most practical and convenient arrangement is for the ultrasound to be performed earlier on the day of outpatient follow-up.

Micturating cysto-urethrogram (MCU) may be necessary but the decision to perform this invasive and sometimes distressing investigation needs to be individualised. The value of demonstrating vesicoureteric reflux in assisting future management is controversial. It is currently a matter of physician preference. It may be done in children under 6 months of age (especially boys), and may be necessary for older children according to circumstances. MCU should not be arranged from the Emergency Dept. and discussion of the pros and cons of this with the parents can be undertaken at outpatient review.

Goto Top

Follow up

Refer all children with proven UTI for follow up in the General Paediatric Clinic, or by the child's own paediatrician.

Goto Top

Notes

Urine specimens

Supra-pubic aspiration (SPA)

  • For children too young to obtain an MSU, and with a high probability of UTI, or who are unwell warranting more invasive investigation.
  • Always send for culture
  • Any growth from SPA urine usually indicates infection (but note possible contamination by skin commensals or faecal flora may produce a mixed growth).

Catheter Specimens

  • Useful after failed attempt at SPA.
  • SPA remains the preferred method.
  • Always send for culture. Discard first few drops of urine.
  • Any growth >103 CFU/litre indicates infection.

Midstream urine (MSU)

  • Can be obtained from children who can void on request. Wash genitalia with water and dry. The first few mls to be voided are not collected then a specimen is obtained. 
  • A pure growth of > 108 CFU/litre indicates infection. A pure growth > 105 may indicate early infection and requires a repeat specimen.

Full ward test (dipstick) Urine

  • Full ward tests (FWT) can detect urinary protein, blood, nitrites (produced by bacterial reduction of urinary nitrate), and leucocyte esterase (an enzyme present in white blood cells).
  • FWT's are a screening test only. If you really suspect UTI - send a specimen for micro and culture.
  • Remember:
    • Blood and protein are unreliable markers of UTI
    • Not all organisms produce nitrites and nitrites take time to develop in urine and so have poor sensitivity. They may appear in other infections.
    • Not all patients with UTI have pyuria, especially the very young & neutropaenic patients. Leucocyte esterase can only be detected with relatively high WBC counts in urine. So the test has low sensitivity.
    • Leucocytes from local sources (vagina, foreskin) may contaminate urine. Leucocytes appear in the urine in many other febrile illnesses eg URTI, pneumonia, etc. So the specificity is low.

Goto Top

Other Resources

 

webmaster. © RCH.