This site is intended for health professionals only

UTI in children: more than a wee problem

The National Institute for Health and Clinical Excellence published guidance on the diagnosis and management of urinary tract infection in children in August 2007.(1) Dr Rachel Pryke explores and summarises some of the important aspects of this guidance

Rachel Pryke
MB BS MRCGP
GP and author
Winyates Health Centre
Redditch Worcestershire
Author of Weight matters for children. Oxford: Radcliffe Publishing; 2006.

Urinary tract infection (UTI) is one of the commonest infections in childhood and will have affected around 10% of people by the time they reach their teenage years.(2)
Children do not necessarily complain of the typical symptoms of cystitis found in adults - those of burning or stinging (dysuria,) frequency of micturition and lower abdominal and flank pain. Indeed, symptoms may be very nonspecific and the possibility of UTI should be borne in mind in any child who has unexplained illness.Urinary tract infection (UTI) is one of the commonest infections in childhood and will have affected around 10% of people by the time they reach their teenage years.(2)
Children do not necessarily complain of the typical symptoms of cystitis found in adults - those of burning or stinging (dysuria,) frequency of micturition and lower abdominal and flank pain. Indeed, symptoms may be very nonspecific and the possibility of UTI should be borne in mind in any child who has unexplained illness.

Presentation
The common presenting symptoms vary depending on a child's age. Table 1 shows typical and less usual presenting symptoms for different age groups.

[[nip 40_tabl1_36]]

UTI should be considered in any child with unexplained fever. Although in older children and adults UTI is much commoner in females, it is more frequent in boys up to the age of one.
Urine is usually sterile. If it becomes infected, white blood cells appear, as shown by finding leucocytes on dipstick testing. Some bacteria cause production of nitrites in urine, although they may take a little time to appear so may not be present early on in UTI. The finding of both leucocytes and nitrites is highly suggestive of bacterial UTI.

The symptoms and signs from UTI depend on the extent of infection:

  • Bacteriuria, or pus in the urine, can be asymptomatic.
  • Symptomatic bacteriuria is where infection causes inflammation within the urinary tract producing abdominal discomfort, flank pain and urinary symptoms such as incontinence or frequency, but not systemic illness.
  • Acute pyelonephritis, where infection passes up from the bladder to the kidney, is characterised by flank, loin and suprapubic pain plus general systemic illness with fever, rigors and vomiting. Acute pyelonephritis requires urgent assessment because it can lead to septicaemia.
  • Chronic pyelonephritis may cause few symptoms or may cause listlessness, failure to thrive, intermittent fever and, most importantly, chronic renal damage. Assessment and follow-up in secondary care is mandatory. The patient is likely to require long-term antibiotic prophylaxis following investigation of any underlying cause.

Box 1 lists risk factors that increase the likelihood of developing a UTI. Around 40% of children with UTI are found to have abnormality of the renal tract such as:

  • Hydronephrosis (the collecting system of the kidney is distended).
  • Vesico-ureteric reflux (urine passes back up the ureter towards the kidney).
  • Duplex collecting systems (presence of additional kidney tissue and/or collecting system on one or both sides).
  • Megaureter (the ureter is distended along its length).

[[nip 40_box1_36]]

Making a diagnosis
UTI may be evident from the history, although this is less likely in younger children because of the nonspecific nature of presentation. It should be considered in any child with unexplained fever.
First make an initial assessment of the severity of feverish illness.
Attempts should be made to collect a urine sample if there are symptoms and signs of UTI, if there is unexplained fever over 38°C, or if treatment of apparent infection elsewhere in the body has been unsuccessful, because UTI may coexist with other infection.

Collecting a urine sample
Try to obtain a "clean catch" specimen from an infant or a midstream sample from an older child. Social cleanliness should be adequate, but avoid contaminating the top of the urine bottle.
If a clean catch is not possible, then use a urine collection pad. This is an absorbent pad that is put inside a clean nappy, checked every 10 minutes until wet then urine is aspirated with a syringe. Specimens are easily contaminated, but a negative finding is reliable. Alternatively, apply a urine specimen bag. Hold the infant upright and transfer the sample from the bag as quickly as possible. Contamination is common, but again a negative finding is reliable.
A positive result or lack of success with the above methods may necessitate further confirmation with a suprapubic aspiration of urine. This is a secondary care procedure and is the most accurate method of urine collection in children under two years.
Catheter sampling is an alternative, but is less commonly carried out.
Treatment should not be delayed in an ill child because of failure to collect a specimen.

Testing and treating
If UTI is suspected, the NICE guidance recommends an age-appropriate management plan:

  • Infants younger than three months:
  1. Refer for paediatric assessment.
  2. Urgent microscopy and culture.
  3. Manage in line with NICE clinical guideline 47 Feverish Illness in Children.(3)
  4. Arrange imaging of the renal tract according
    to the detailed schedule in NICE guideline for all infants under six months with UTI.
  • Children between three months and three years:
  1. Base testing and management on likelihood of UTI from symptoms and on degree of risk of serious illness, as outlined in Table 2.
  2. Send a sample for microscopy and culture in all suspected cases.
  3. Arrange imaging only if there is recurrent or atypical UTI (infants over six months and under three years)
  • Children over three years:
  1. Use dipstick testing in firstline assessment (see Table 3).
  • Send urine sample for culture if:
  1. Any evidence of leucocytes or nitrites.
  2. Prone to recurrent UTI.
  3. Infection has not promptly responded to treatment. 
    The clinical picture does not tie with the dipstick result.
  4. Arrange imaging only if there is recurrent or atypical UTI.

If culture comes back showing a mixed growth, consider contamination of sample. Repeat the sample if child is asymptomatic. Treat if the child is symptomatic. Consider paediatric assessment if the problem is recurrent despite careful specimen collection.

[[nip 40_table2_37]]

[[nip 40_table3_38]]

Which antibiotic?
Dosage schedules should be calculated according to the child's weight and age, and further details can be found in the BNF for Children (see Resources).Choose according to local guidance from your microbiology laboratory, which should monitor resistance patterns and issue local guidance accordingly.

  • Double check allergy status first.
  • Choose a different antibiotic if child is already on antibiotic prophylaxis.
  • Do not treat asymptomatic bacteriuria with antibiotics.
  • Consider need for antibiotic prophylaxis if recurrent UTI, but not after first UTI.

Preventing recurrence
Evidence is not conclusive on which steps reduce chance of further UTI, but in combination with common sense, the following steps are suggested:

  • Address constipation and toileting problems.
  • Ensure good fluid intake regularly.
  • Avoid tight clothing, bubble baths and chemical irritants.
  • Ensure good hygiene, including "wiping from front to back" for girls.
  • Consider prophylaxis if recurrent and/or if known significant renal tract abnormality.
  • Consider screening of siblings as vesico-ureteric reflux is found in around 30% of siblings.

Conclusion
UTI in children is a significant cause of acute childhood illness and may be responsible for renal scarring and renal failure, hence its detection, treatment and long-term prevention is very important.

References

  1. NICE. Urinary tract infection: diagnosis, treatment and long-term management of urinary tract infection in children. Clinical guideline 54. London: NICE; 2007.
  2. Jakobsson B, Esbjorner E, Hansson S. Minimum incidence and diagnostic rate of first urinary tract infection. Pediatrics 1999;104:222-6.
  3. NICE. Feverish illness in young children. Clinical
    guideline 47. London: NICE; 2007.


Resources
BNF for Children
W: www.bnfc.org

Diagnosis and Management of Urinary Tract Infection in Children: Summary of NICE Guidance
Mori R, Lakhanpaul M, Verrier-Jones K. BMJ 2007;335:395-7.

Management of Suspected Bacterial Urinary Tract Infection in Adults.
Scottish Intercollegiate Guidelines Network; 2006. Available from: http://www.sign.ac.uk

ABC of One to Seven
Valman B. London; BMJ Books; 2001.

Your comments: (Terms and conditions apply)

"What if protein is found on dipstick, does this not indicate infection?" - Name and address supplied