Urinary Tract Infection in Under 16s: Diagnosis and Management

Overview

This Guidelines summary covers diagnosing and managing first or recurrent upper or lower urinary tract infection (UTI) in babies, children and young people under 16.

Recommendations included are on diagnosis, acute management, and imaging tests. Recommendations on surgical intervention, follow up, and information and advice are not included.

For a complete set of recommendations, refer to the full guideline.

Diagnosis

Symptoms and Signs

• Test the urine of babies, children and young people who have symptoms and signs that increase the likelihood that a urinary tract infection (UTI) is present (see table 1 and the explanation of how to use the table beneath it).
• Consider testing the urine of babies, children and young people if they are unwell and there is a suspicion of a UTI but none of the signs or symptoms listed in table 1 are present.
• Refer babies under 3 months with a suspected UTI (see table 1 and the second recommendation in this section) to paediatric specialist care, and:
  • send a urine sample for urgent microscopy and culture
  • manage in line with the sections on management by the non-paediatric practitioner and management by the paediatric specialist in the NICE guideline on fever in under 5s: assessment and initial management.
• Do not routinely test the urine of babies, children and young people 3 months and over who have symptoms and signs that suggest an infection other than a UTI. If they remain unwell and there is diagnostic uncertainty, consider urine testing.

Table 1: Symptoms and Signs That Increase or Decrease the Likelihood That a UTI Is Present

• When using the table, be aware that:
  • The symptoms and signs in this table should be used to inform a decision about whether urine collection and testing is necessary.
  • It is not an exhaustive list of symptoms or signs and should be used as a guide alongside clinical judgement.
  • The presence or absence of a single symptom or sign in isolation in either column should not necessarily be used to decide whether or not to test for UTI.
  • Multiple symptoms and signs will probably increase the likelihood that there is a UTI.
  • It may be useful to consider alternative diagnoses where the symptoms and signs decrease the likelihood that a UTI is present.
• For babies or children under 5 with fever with no obvious cause where a UTI is no longer suspected, see the NICE guideline on fever in under 5s: assessment and initial management.
• Paediatric specialists should consult the section on management by the paediatric specialist in the NICE guideline on fever in under 5s: assessment and initial management, which covers when to test urine for a UTI in babies and children under 5 with fever who are in their care. 
• Avoid delay when collecting and testing the urine sample. If the sample cannot be collected at the consultation, advise the parents or carers (as appropriate) to collect and return the urine sample as soon as possible, ideally within 24 hours.See the sections on Urine collection, preservation and testing.
• If a baby, child or young person has suspected sepsis, assess and manage their condition in line with the NICE guideline on sepsis: recognition, diagnosis and early management. 
• If a baby of up to and including 28 days corrected gestational age has suspected or confirmed bacterial infection, assess and manage their condition in line with the NICE guideline on neonatal infection: antibiotics for prevention and treatment. For early-onset neonatal infection, see the section on assessing and managing the risk of early-onset neonatal infection after birth, and for late-onset neonatal infection, see the section on risk factors for and clinical indicators of possible late-onset neonatal infection in the NICE guideline on neonatal infection: antibiotics for prevention and treatment.

Assessment of Risk of Serious Illness

• Assess the level of illness in babies and children in accordance with the section on clinical assessment of children with fever in the NICE guideline on fever in under 5s: assessment and initial management.

Urine Collection

• Take urine samples from children and young people before they are given antibiotics. This is in line with the NICE antimicrobial prescribing guidelines on pyelonephritis (acute) and urinary tract infection (lower).
• Babies and children with a high risk of serious illness should have a urine sample taken, but treatment should not be delayed if a urine sample cannot be obtained.
• Use a clean catch method for urine collection wherever possible.
• If a clean catch urine sample is not possible, use other non-invasive methods such as urine collection pads. It is important to follow the manufacturer’s instructions when using urine collection pads.
• Do not use cotton wool balls, gauze or sanitary towels to collect urine from babies and children.
• Use catheter samples or suprapubic aspiration (SPA) when it is not possible or practical to collect urine by non-invasive methods. Use ultrasound guidance to confirm that there is urine in the bladder before SPA

Urine Preservation

• Immediately refrigerate or use boric acid to preserve urine samples that are to be cultured but cannot be cultured within 4 hours of collection.
• Follow the manufacturer’s instructions when using boric acid to ensure the correct specimen volume and avoid potential toxicity against bacteria in the specimen.

Urine Testing

• Use dipstick testing for babies and children between 3 months and 3 years with suspected UTI, and:
  • if both leukocyte esterase and nitrite are negative:
    • do not give antibiotics
    • do not send a urine sample for microscopy and culture unless at least 1 of the criteria in the first recommendation below table 2 apply.
  • if leukocyte esterase or nitrite, or both are positive:
    • send the urine sample for culture
    • give antibiotics
• Use the urine-testing strategy for children aged 3 years or older shown in table 2. Assess the risk of serious illness in line with the section on clinical assessment of children with fever in the NICE guideline on fever in under 5s to ensure appropriate urine tests and interpretation, both of which depend on the child’s age and risk of serious illness.

Table 2: Urine Dipstick Testing Strategies for Children 3 Years or Older

Dipstick testing for leukocyte esterase and nitrite is diagnostically as useful as microscopy and culture, and can safely be used.

• Send urine samples for culture if a baby or child:
  • is thought to have acute upper UTI (pyelonephritis; see the section on clinical differentiation between acute upper UTI and lower UTI)
  • has a high to intermediate risk of serious illness (see the section on assessment of risk of serious illness)
  • is under 3 months old
  • has a positive result for leukocyte esterase or nitrite
  • has a recurrent UTI
  • has an infection that does not respond to treatment within 24 to 48 hours, if no sample has already been sent
  • has clinical symptoms and signs but dipstick tests do not correlate.
• Interpret microscopy results as shown in table 3.
• Use clinical criteria for decision making if a urine test does not support findings, because in a small number of cases, this may be the result of a false negative. 

Table 3: Interpreting Microscopy Results

History and Examination of Confirmed UTI

• Record the following risk factors for UTI and serious underlying pathology:
  • poor urine flow
  • history suggesting previous UTI or confirmed previous UTI
  • recurrent fever of uncertain origin
  • antenatally diagnosed renal abnormality
  • family history of vesicoureteral reflux (VUR) or renal disease
  • constipation
  • dysfunctional voiding
  • enlarged bladder
  • abdominal mass
  • evidence of spinal lesion
  • poor growth
  • high blood pressure

Clinical Differentiation Between Acute Upper UTI and Lower UTI

• Assume a diagnosis of acute upper UTI in babies or children who have either:
  • bacteriuria and fever of 38°C or higher or
  • bacteriuria, fever lower than 38°C and loin pain or tenderness.
• Assume that babies and children who have bacteriruia but no systemic symptoms or signs have lower UTI (cystitis).

Laboratory Tests for Localising UTI

• Do not use C-reactive protein alone to differentiate acute upper UTI from lower UTI in babies and children.

Acute Management

Note that the antibiotic requirements for babies and children with conditions that are outside the scope of this guideline (for example, babies and children already known to have significant pre-existing uropathies) have not been addressed and may be different from those given here.

• Immediately refer babies and children with a high risk of serious illness (see the section on assessment of risk of serious illness) to a paediatric specialist.
• Immediately refer babies under 3 months with a suspected UTI to a paediatric specialist.
• Paediatric specialists should give babies under 3 months with a suspected UTI parenteral antibiotics in line with the section on management by the paediatric specialist in the NICE guideline on fever in under 5s.
• Consider referring babies and children over 3 months with upper UTI to a paediatric specialist.
• Give babies and children over 3 months with an acute upper UTI antibiotics in line with the NICE guideline on pyelonephritis (acute): antimicrobial prescribing.
• Give babies and children over 3 months with lower UTI antibiotics in line with the NICE guideline on urinary tract infection (lower): antimicrobial prescribing.
• For information about treating babies and children who were already on prophylactic antibiotics who then developed a UTI see the NICE guidelines on pyelonephritis (acute): antimicrobial prescribing, urinary tract infection (lower): antimicrobial prescribing and urinary tract infection (recurrent): antimicrobial prescribing.
• Do not use antibiotics to treat asymptomatic bacteriuria in babies and children.
• Laboratories should monitor patterns of urinary pathogen resistance and make this information routinely available to prescribers.

Preventing Recurrence

• Manage dysfunctional elimination syndromes and constipation in babies and children who have had a UTI.
• Encourage children who have had a UTI to drink enough water to avoid dehydration.
• Ensure that children who have had a UTI have access to clean toilets when needed and do not have to delay voiding unnecessarily.

Prophylactic Antibiotics

• Do not routinely give prophylactic antibiotics to babies and children following first-time UTI.
• See the NICE guideline on urinary tract infection (recurrent): antimicrobial prescribing for prophylactic antibiotic treatment for recurrent UTI in babies and children.
• Do not give prophylactic antibiotics to babies and children with asymptomatic bacteriuria.

Imaging Tests for Localising UTI

• Do not routinely use imaging to localise UTI.
• In rare instances when it is clinically important to confirm or exclude acute upper UTI, use either:
  • power doppler ultrasound or
  • a dimercaptosuccinic acid (DMSA) scintigraphy scan if power doppler ultrasound is not available or the diagnosis has not been confirmed.

Imaging Tests

For tables on recommended imaging schedules, refer to the full guideline.

See box 1 for definitions of atypical and recurrent urinary tract infection.

• Send babies and children with atypical UTI (see box 1) for a urinary tract ultrasound during the acute infection, to identify structural abnormalities such as obstruction and to ensure prompt management, as outlined in tables 4, 5 and 6 (see the full guideline).
• Send babies younger than 6 months with first-time UTI that responds to treatment for ultrasound within 6 weeks of the UTI, as outlined in table 4 (see the full guideline).

 

• Do not routinely send babies and children over 6 months with first-time UTI who respond to treatment for an ultrasound, unless they have atypical UTI as outlined in tables 5 and 6 (see the full guideline).
• Babies and children who have had a lower UTI should be sent for ultrasound (within 6 weeks) only if they:
  • are younger than 6 months or
  • have had recurrent infections.
• Use a DMSA scan 4 to 6 months after the acute infection to detect renal parenchymal defects in babies and children, as outlined in tables 4, 5 and 6 (see the full guideline).
• If the baby or child has a subsequent UTI while waiting for a DMSA scan, review the timing of the scan and consider doing it sooner.
• Do not routinely use imaging to identify VUR in babies and children who have had a UTI, except in specific circumstances as outlined in tables 4, 5 and 6 (see the full guideline).
• When a micturating cystourethrogram (MCUG) is done, give prophylactic antibiotics orally for 3 days with the MCUG on the second day.
• Send babies and children who have had a UTI for imaging, as outlined in tables 4, 5 and 6 (see the full guideline).

In a baby with a non-E. coli urinary tract infection that is responding well to antibiotics and has no other features of atypical infection, a non-urgent ultrasound can be requested, to happen within 6 weeks.

While MCUG should not be performed routinely it should be considered if the following features are present:

• dilatation on ultrasound
• poor urine flow
• non-E. coli -infection
• family history of VUR.

In babies and children with a non-E. coli urinary tract infection that is responding well to antibiotics and has no other features of atypical infection, a non-urgent ultrasound can be requested, to happen within 6 weeks.

Ultrasound in toilet-trained children should be performed with a full bladder with an estimate of bladder volume before and after urination.

In a child with a non-E. coli urinary tract infection that is responding well to antibiotics and has no other features of atypical infection, a non-urgent ultrasound can be requested, to happen within 6 weeks.