Dr Kjell Tullus explains how an improved approach to the diagnosis and management of UTI in children can avoid misdiagnosis and reduce the risk of renal scarring
  • All infants, children, and young people who present with a temperature of 38°C or higher without a clear cause for the temperature should have their urine tested
  • If the urine test raises a suspicion of a UTI, then antibiotic treatment should be started immediately, before the culture results are known
  • The antibiotic therapy should be modified appropriately when the results of the urine culture are known
  • A febrile UTI can cause irreversible kidney damage, which can be prevented by early treatment
  • A small but very important minority of children with a febrile UTI will have an underlying urological malformation:
    • it is important to identify and record risk factors for these abnormalities
    • children with such risk factors should be referred for further investigation
  • It is important to educate the family to always seek medical help when the child has recurrent episodes of a high temperature without an obvious cause.

Read this article to find out more about:
  • the different forms of UTI in children
  • when antibiotics should be initiated
  • what advice should be given to patients and parents/carers.

Urinary tract infections (UTIs) in children are very common and occur in 11% of all girls and 3.6% of all boys under the age of 16 years in the UK.1 The scope of this article is to point out important areas for improvement in the management of UTI in children.

Clinically, three rather distinct forms of UTI can be defined:2

  • febrile UTI (mostly signifying acute pyelonephritis [APN])
  • acute cystitis
  • asymptomatic bacteriuria.

A febrile UTI is typically a disease of the infant and small child (both boys and girls); cystitis is most commonly seen in young girls. It is very important to separate these two conditions as they differ between causes, management, outcomes, and associated risks.

Older children more often have lower urinary tract infection and symptoms typical of cystitis.2

Febrile urinary tract infection—acute pyelonephritis

Acute pyelonephritis is the most common UTI in small children. Children typically present with a high temperature (38°C or higher) and are quite unwell. In the majority of cases, APN is caused by the highly virulent Escherichia coli (E. coli).3-5 Some 30% of children with APN have vesicoureteral reflux (VUR), and a small percentage (approximately 1%–2%) have clinically important, often obstructive, urinary tract malformations.2

Children with APN need prompt recognition, diagnosis, and treatment. Delayed treatment can cause irreversible kidney scarring, and so an antibiotic course should be started in all children with a suspicion of UTI as soon as a good urine sample has been obtained and before the result of the urine culture is known.2,6 All children with APN in the acute phase should be referred to a paediatrician for further management; infants younger than 3 months with a possible UTI, or at risk of serious illness, should be referred urgently to the care of a paediatric specialist.2,7

Acute cystitis

Most cases of cystitis occur in girls of a few years of age, or older. They tend to have several local symptoms of pain, urgency, and sometimes macroscopic haematuria. In general, these children are well in themselves, with no (or just a slight) fever.2

A single episode of cystitis does not point to any specific cause, but recurrent episodes are related to functional bladder problems. These occur typically in girls who do not ‘listen to their bladders’: they do not go to the toilet when they need to. Voiding postponement, with fewer ‘wees’ per day than normal (i.e. fewer than about 4–5 per day) and residual urine are typical features. Many children also have urgency and daytime urine leakage, even between episodes of cystitis.

Children with cystitis should be treated with a 3-day course of a narrow-spectrum antibiotic (e.g. nitrofurantoin or trimethoprim), which can be changed, if necessary, when the results of the urine culture are known.2

Further investigations are not needed in an uncomplicated case but girls with several recurrent episodes of cystitis should have their bladder habits reviewed. They should be given advice regarding toilet habits, and any co-existing constipation should be treated. Some of these children will benefit from referral to a paediatrician with an interest in these problems.2

Asymptomatic bacteriuria

Asymptomatic bacteriuria (ABU) is a relatively common condition that occurs mainly in girls who have recurrent episodes of cystitis, as well as in girls who have had no episodes of symptomatic UTI. The bladders of these children can, in association with their dysfunction, become colonised with bacteria that do not provoke symptoms. It has been shown that it is best to leave the bacteria untreated because they do not cause problems and there is a very high chance of recurrence despite treatment.2

NICE quality standard for urinary tract infection in infants, children, and young people under 16

NICE quality standard (QS) 36 on Urinary tract infection in infants, children and young people under 16?8 (see www.nice.org.uk/QS36) was issued in July 2013. The four statements that make up QS36 are listed in Table 1, below, and are discussed below.

It is important to assure prompt, accurate diagnosis and treatment of febrile UTIs, particularly in small children. The small number of children with suspicion of an underlying severe abnormality of the urinary tract need to be identified and referred for specialist care.

Presentation with unexplained fever of 38?C or higher—statement 1

Infants and children can often present with a febrile UTI without any localising symptoms.9 They can have a high temperature and be very unwell in themselves, but exhibit no other signs or symptoms suggestive of a UTI. A febrile UTI has the potential to cause irreversible scarring to one or both kidneys. This risk increases with the time taken for the infection to respond to appropriate treatment. It is, therefore, very important either to diagnose or to exclude a UTI in all infants and children without another clear cause for a febrile illness. Quality statement 1 requires that infants, children, and young people presenting with unexplained fever of 38?C or higher have a urine sample tested within 24 hours.8,9 If a UTI is suspected as a consequence of this initial urine test, then empiric antibiotic treatment should be started before the results of the urine culture are known.2

History and examination: recording of risk factors—statement 2

A few percent of infants and children with a febrile UTI have severe underlying malformations of their urinary tract. Many of these are obstructive malformations, the most common being posterior urethral valves in boys. Obstructions also occur at other places in the urinary tract. A proportion of these children also have marked VUR, which increases the risk of scarring and recurrent infections.2

Previously, all children who had a febrile UTI underwent several investigations to look for malformation and gross VUR. These investigations often included ultrasound, renal scintigraphy (dimercaptosuccinic acid scan), and a micturating cystourethrogram. These investigations are quite uncomfortable for children, involve exposure to radiation, and can also occasionally cause an infection. Furthermore, the yield from the investigations was relatively low, because few relevant malformations were detected.

Recent clinical guidance from NICE on UTI,2 therefore, does not recommend imaging in all children after a first episode of a febrile UTI. Instead, NICE CG54 recommends that children should be assessed for a list of risk factors for UTI and other serious underlying conditions, which, if found, should be recorded in the patient notes. Children with risk factors should be referred to the local paediatrician for further investigations.

Risk factors suggestive of malformation include:2

  • poor urine flow
  • antenatally-diagnosed renal abnormality
  • enlarged bladder
  • abdominal mass
  • evidence of a spinal lesion.

Another group of risk factors that might indicate renal damage include:2

  • poor growth
  • high blood pressure.

Other risk factors focus on the infection (see text under heading for statement 3, below) and include:2

  • infection with non-E. coli bacteria
  • slow response to the prescribed antibiotic.

All children with the above risk factors should be referred to a paediatrician.

Laboratory reporting: differentiation of E. coli and non-E. coli organisms—statement 3

There is an increased risk of serious underlying pathology for children with UTI that is not caused by E. coli.8 This is because the most important host defence factor for the urinary tract is urine flow—E. coli use fimbriae to attach themselves to the uroepithelial cell lining to prevent themselves being washed out with the flow of urine. Only E. coli can do this—other bacteria need ‘help’ to cause an infection, from a malformation that creates stagnant and residual urine.

It is, therefore, very important to know which bacterial species is causing the UTI in order to evaluate the possibility that a child may have a malformation requiring further investigation.8

Providing information about recognising re-infection—statement 4

Some children will experience a recurrence of UTI, and it is important that this is recognised and treated quickly. As with the first infection, recurrences of UTI mainly have no localising symptoms. The child has a temperature and can be quite unwell but there are no other presenting symptoms.

These recurrences can also cause irreversible kidney damage and so the child will benefit from early treatment. It is, therefore, very important that children and young people who have had a UTI are:

  • told about the risk of recurrence of UTI
  • given information about how to recognise re-infection
  • advised to seek medical advice straight away in those circumstances.

A useful downloadable summary of information about UTI for parents and carers can be found at infokid.org.uk/sites/default/files/topics/KID-UTI-overview-2013-12-04.pdf10

In our clinic, we normally ask the children/young people and their carers to point out to the GP, A&E doctor, or whichever person they see when the child is unwell, the need to do a urine sample if no other cause for the temperature is found.

Table 1: Quality standard for urinary tract infection in infants, children and young people under 16
No. Quality statement
1 Infants, children and young people presenting with unexplained fever of 38°C or higher have a urine sample tested within 24 hours.
2 Infants, children and young people with a urinary tract infection have risk factors for urinary tract infection and serious underlying pathology recorded as part of their history and examination.
3 Infants, children and young people with a urinary tract infection caused by coliform bacteria have results of microbiology laboratory testing differentiated by Escherichia coli (E. coli) or non-E. coli organisms.
4 Children and young people who have had a urinary tract infection are given information about how to recognise re-infection and to seek medical advice straight away.
NICE (2013) QS36. Quality standard for urinary tract infection in infants, children and young people under 16. Available at: www.nice.org.uk/guidance/QS36. Reproduced with permission

Role of primary care

As most unwell children are seen by their GP, primary care is essential in the management of children with a UTI, both to prevent unnecessary suffering and to prevent kidney damage. Helpful information for parents and carers on UTI and kidney conditions in babies, children, and young people can be found at infokid.org.uk10


Urinary tract infection in children is a potentially serious condition as it can irreversibly scar the kidneys if not treated promptly. Infants, children, and young people with a UTI will have a high temperature and often be quite unwell. A small but significant minority of these UTIs will be caused by an important urological malformation, which may require surgery. Children with certain risk factors should undergo selected imaging to pick up any such malformations.

Proportion of children with:

  • unexplained fever who have their urine tested
  • increased leucocytes and/or a positive nitrite test who are started on antibiotics
  • a proven febrile UTI who have risk factors for underlying malformations recorded

Proportion of:

  • urine cultures that have non-E. coli organisms differentiated from other species of bacteria
  • families that are given verbal and/or written information about
  • recurrent UTI
  • This quality standard reinforces NICE Clinical Guideline (CG) 54 on Urinary tract infection in children: diagnosis, treatment and long-term management, published in 2007 (see guidance.nice.org.uk/CG54)11
  • The full version of NICE CG54 (see www.nice.org.uk/nicemedia/live/11819/36028/36028.pdf)2 contains a very good algorithm for the management and investigation of UTIs. Commissioners should encourage all providers (but especially primary care, out-of-hours services, and urgent care centres) to refer to and use this algorithm:
    • commissioners could consider an education campaign aimed at providers to raise the awareness of UTI as a cause of fever in pre-verbal children
  • Commissioners (with providers) could design a proforma to be used to refer children with confirmed UTI for specialist opinion, to ensure that:
    • only those children who qualify for further investigation are referred to paediatricians
    • those children who do qualify for further investigation are indeed referred to paediatricians
  • Children who have had a confirmed UTI (and their families) could be issued with a urine-sample bottle and an advice leaflet that:
    • highlights the need for them to seek help if the child has further fevers
    • instructs the family to raise awareness of the child’s previous UTI with the health service they present to, and the need for a urine sample to be taken.
  1. Coulthard M, Lambert H, Keir M. Occurrence of renal scars in children after their first referral for urinary tract infection. BMJ 1997; 315 (7113): 918–919.
  2. National Collaborating Centre for Women’s and Children’s Health. Urinary tract infection in children: diagnosis, treatment and long-term management. London: Royal College of Obstetricians and Gynaecologists, 2007. Available at: www.nice.org.uk/nicemedia/live/11819/36028/36028.pdf
  3. Montini G, Tullus K, Hewitt I. Febrile urinary tract infections in children. N Engl J Med 2011; 365 (3): 239–250.
  4. Tullus K. What do the latest guidelines tell us about UTIs in children under 2 years of age? Pediatr Nephrol 2012; 27 (4): 509–511.
  5. Tullus K. A review of guidelines for urinary tract infections in children younger than 2 years. Pediatr Ann 2013; 42 (3): 52–56.
  6. Toffolo A, Ammenti A, Montini G. Long-term clinical consequences of urinary tract infections during childhood: a review. Acta Paediatr 2012; 101 (10): 1018–1031.
  7. NICE. Feverish illness in children: assessment and initial management in children younger than 5 years. Clinical Guideline 160. London: NICE, 2013. Available at: www.nice.org.uk/cg160
  8. NICE website. Urinary tract infection in infants, children and young people under 16. Quality Standard 36. www.nice.org.uk/guidance/QS36 (accessed 18 February 2014).
  9. Tullus K. Difficulties in diagnosing urinary tract infections in small children. Pediatr Nephrol 2011; 26 (11): 1923–1926.
  10. Royal College of Paediatrics and Child Health, British Association for Paediatric Nephrology, British Kidney Patient Association. infokid website. infokid.org.uk (accessed 6 March 2014).
  11. NICE. National Institute for Health and Care Excellence. Urinary tract infection in children: diagnosis, treatment and long-term management. Clinical guideline 54. London: NICE, 2007. Available at: www.nice.org.uk/guidance/CG54 G