Background to condition

• UTI cannot be diagnosed on symptoms alone.
• There is no indication for culture of urine from a bag specimen.
• In children that can void on request an MSU is an adequate sample. In younger children a clean catch is often adequate. In septic infants an SPA or catheter urine may be required.
• Urinary dipstick testing is only a screening test for UTI. It has poor sensitivity and specificity especially in children less than 3 years of age.
  
• 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 - this is rare but documented in babies less than 4 weeks of age. Do not omit an LP in a young baby if you are considering meningitis 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.

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 UTI 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.

Investigation:

• A clean specimen is required for the diagnosis of UTI. See urinary specimen

Acute management

• Any child who is unwell, and most children under 6 months, should be admitted for i.v. antibiotics. Consider a blood culture and LP if less than 4 weeks old.
• A shocked child will require fluid resuscitation. See iv fluid guidelines
• Recommended iv antibiotics are gentamicin and benzylpenicillin. Drug doses
• Remember to do gentamicin levels pre-the third dose if planning to continue gentamicin for more than 3 doses.

If oral medication is appropriate:

Infants and Children

• Trimethoprim 4mg/kg (150mg max) BD (only tablets generally available in community, RCH pharmacy make 10mg/mL suspension for RCH patients)
  or
• Trimethoprim and sulphamethoxazole (8mg-40mg per mL) 0.5 ml/kg (20ml max) BD
  or
• Cephalexin 15mg/kg (500mg max) TDS
  
  

10 days total if < 2years, 7 days if older

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

Routine prophylaxis is no longer recommended. (see notes)

Consider consultation with local paediatric team:

• Child under 6 months of age
• Child with known renal tract abnormalities
• Any child who looks severely unwell and needing full septic work up, see fever under 3 years old

When to consider transfer to tertiary centre:

• Child requiring care beyond the comfort level of the hospital
  
  For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.
  

Follow up:

Investigations 

• Children with atypical UTI, those not responding to treatment within 48 hours, and boys <3 months of age should have a renal ultrasound to exclude renal obstruction.
• Children <6 months should have a renal ultrasound within 6 weeks of diagnosis. It should be performed during the illness if the UTI is atypical or not responding to antibiotics within 48 hours.
• Older children do not require and ultrasound post first UTI, but should have a renal ultrasound for recurrent UTI. 
• Other imaging modalities may be considered as per NICE guidelines. 
  
  

Parent information sheet:

Here

Additional notes:

• Prophylactic  antibiotics- prophylactic antibiotics do have a small positive effect (8%) in the reduction of further UTI. There has been no benefit demonstrated in children with vesico-ureteric reflux. Prolonged use of antibiotics has been associated with future infections with resistant organisms. Nitrofurantoin has been shown to be the most effective prophylaxis, but has a high rate of adverse events.

Urinary specimens:

Suprapubic aspiration (SPA)

• Do not delay antibiotics in the septic child.
• For children too young to obtain an MSU, and with a high probability of UTI, or who are unwell warranting more invasive investigation. Click here to learn how to do an SPA, including the use of bedside ultrasound
• 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 probably indicates infection.

Clean catch urine

• For children who are unable to void on request, and who are not too unwell.
• There are 2 techniques. In both it is better to wash the genitalia just with water (no soap, no antiseptics).
  • 1.      Leave the baby exposed and give parents a sterile urine container to try and catch mid part of the urine stream (no dangling the penis in the pot, or scraping the urine off the perineum!)
    
    
  •  2.      Leave the baby exposed with legs in frog leg posture and a small clean dish between legs to catch the urine flow. Most use a new small aluminium pie dish (doesn't need to be sterilised - they are very clean when they come out of the packet).

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 test (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 is a screening test only. If  UTI is suspected, a specimen should be sent for microscopy and culture - particularly for children under 3 years of age.

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.
• Not all patients with UTI have pyuria, especially the very young & neutropenic 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, meningitis etc. So the specificity is low.

Last updated April 2015