urinary tract infection (UTI) in children

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  • a urinary tract infection is an important diagnosis in a child not to miss because infection may damage the developing kidney
  • as with adults, a urinary tract infection in children is defined as more than 10 to the power 5 organisms per ml in voided urine (studies on urine specimens from large numbers of hospital patients confirm that a pure growth of 10^5 organisms per ml or greater is indicative of infection (1)
  • about 2% of boys and 8% or more of girls will develop a urinary tract infection during childhood

Note that in some children, especially boys, the child may not retain urine in the bladder for a long enough period for multiplication to a pure growth of 10^5 organisms per ml to occur. In these cases a pure growth of 10^4-10^5 organisms may indicate infection.

NICE note that clinical features suggestive of UTI, in a child less than 5 years, are:

  • vomiting
  • poor feeding
  • lethargy
  • irritability
  • abdominal pain or tenderness
  • urinary frequency or dysuria
  • offensive urine or haematuria

NICE now state if suspected UTI is an infants younger than 3 months then:

  • there are concerns about sepsis in infants under 3 months with suspected UTI, and usual practice is referral rather than the GP managing symptoms. So the committee recommended that all children under 3 months should be referred to specialist paediatric care and have a urine sample sent for urgent microscopy and culture


  • infants and children presenting with unexplained fever of 38°C or higher should have a urine sample tested within 24 hours

  • infants and children with an alternative site of infection should not have a urine sample tested. When infants and children with an alternative site of infection remain unwell, urine testing should be considered after 24 hours at the latest


  1. NICE (September 2017). Feverish illness in children Assessment and initial management in children younger than 5 years
  2. Prescriber 2000;11 (18): 21-37.
  3. Jantauch, B.A.t al.. Association of Lewis blood group with urinary tract infection in children. J. Pediatrics 1994;124:863-868
  4. Drug and Therapeutics Bulletin, 35, 65-9.

Last reviewed 09/2019