Urinary tract infection in under 16s: diagnosis and management

Why the committee made the recommendations

The committee discussed evidence from studies that looked at symptoms and signs of urinary tract infections (UTIs). They agreed that it is important to diagnose UTI quickly and accurately to prevent unnecessary suffering and serious complications like renal scarring.

Table 1 shows several symptoms and signs that increase, or decrease, the likelihood of a UTI being present. The committee agreed that the table gives more certainty about which symptoms and signs increase or decrease the likelihood of a UTI being present. The committee also highlighted that many symptoms and signs from the 2007 version of the guideline (dysuria [painful urination], urinary frequency, loin tenderness and bedwetting) are still useful. However, the evidence around many of these symptoms and signs as indicators of UTI was low- or very-low quality. This was because many of the studies were not designed to assess diagnostic accuracy and had poor definitions of the symptoms and signs they reported. Therefore, the committee agreed that due to the remaining uncertainty, the table should be used as a guide alongside clinical judgement.

Because the list in table 1 is not exhaustive, the committee were concerned that some unwell babies, children and young people with a possible UTI might not have further tests if they lack symptoms or signs from the table. There are other symptoms and signs that could suggest a UTI for which no evidence was found or for which data was not reported in the studies. The committee therefore agreed that it may still be necessary to test for UTI, if healthcare professionals suspect UTI despite the absence of any symptoms or signs listed in the table.

The committee also looked at evidence for several algorithms that used combinations of symptoms and signs to help with diagnosis of UTI. None of the algorithms were particularly accurate, so the committee did not recommend their use. However, in the committee's opinion the presence of multiple symptoms or signs will probably increase the likelihood that there is a UTI.

Table 1 does not specify relevant ages for particular symptoms and signs. This is because most of the evidence was for children under 5 years and the trials mostly did not report results by age. The committee agreed that the symptoms and signs could be generalised across age groups, but that clinical judgement was needed when deciding which are relevant for an individual baby, child or young person. This is because age or ability to communicate (or if their symptoms cannot be accurately assessed) will affect the usefulness of a particular symptom or sign. For example, in all ages, the presence of dysuria increased the likelihood that a UTI was present and, when absent, decreased the likelihood. But it may be more difficult to assess in babies, children or young people who are not toilet trained or cannot communicate their symptoms. The committee also chose to include a confirmed history of UTI as a symptom or sign. Although it is not strictly a symptom or sign, it is associated with an increased likelihood of UTI.

The committee looked at evidence for other symptoms and signs that are not included in table 1. These included sleepiness or lethargy, irritability, poor feeding, vomiting, failure to thrive and jaundice. However, these were not found to be clinically useful in suggesting whether a UTI is present based on the evidence included in this review.

The committee noted that some symptoms (for example haematuria [blood in the urine], cloudy urine or dark urine) that were associated with an increased likelihood of UTI, could not be assessed by healthcare professionals without a urine sample. However, the symptoms and signs recommendations in this section are intended to provide guidance about when urine collection and testing is necessary. The committee therefore agreed to include these symptoms or signs in the table, based on the child self-reporting, or parental or caregiver reporting, rather than clinician assessment.

The committee were aware that there may be limitations with these symptoms. For example, darker urine is not specific to urinary tract infection and can be common in those who are unwell and dehydrated (a poor fluid intake not being uncommon in unwell children). Additionally, a report of visible blood, in the committee's opinion, was not common in UTI and would always require further investigation. However, the committee agreed that symptoms and signs that are less specific to the urinary tract might still be useful indicators of a UTI, particularly if they are present in combination with other symptoms and signs.

The committee noted that the symptoms and signs that decrease the likelihood of a UTI may suggest a different site of infection (such as the respiratory tract) but do not necessarily rule out a UTI. The list is not exhaustive (due to limitations in the evidence base) and other symptoms and signs may be present that suggest other sources of infection. The committee agreed that the urine of babies, children and young people aged 3 months and over should not be routinely tested if they have symptoms and signs that suggest another type of infection. This is because it would be clinically unnecessary, waste resources and could increase the stress experienced by the baby or child and their family or carers. However, if they remain unwell and there is diagnostic uncertainty, a urine test may be needed to exclude UTI.

For babies and children under 5 with fever with no obvious cause where a UTI is no longer suspected, the NICE guideline on fever in under 5s: assessment and initial management could provide guidance in identifying the cause of their fever. The guideline also contains a section on diagnostic tests carried out by paediatric specialists on babies and children with fever in their care, including when to test urine for a UTI.

The committee acknowledged that in practice there may be delays in obtaining a urine sample for testing if one cannot be obtained during consultation. They agreed that both urine collection and testing should happen without delay to ensure rapid and accurate diagnosis. However, the committee were aware that urine cultures will not necessarily detect every UTI. Therefore, there is a risk of these babies, children and young people remaining undiagnosed. But they noted that recommendation 1.1.23 addresses this situation.

When making the 2017 recommendation, the committee agreed that there are concerns about sepsis in babies under 3 months with suspected UTI, and usual practice is referral rather than the GP managing symptoms. So, the committee recommended that all babies under 3 months should be referred to specialist paediatric care and have a urine sample sent for urgent microscopy and culture.

The committee identified several gaps in the evidence. Most studies looked at symptoms and signs of UTI in babies and children aged under 5. Those that did include older children still had average ages closer to 5 than 16 and did not present data separately for older children. The committee therefore made a recommendation for research on the symptoms and signs of UTI in children and young people aged 5 years and above but under 16 years. They also made a recommendation for research on whether the symptoms and signs of recurrent UTI in babies, children and young people under 16 differed to acute UTI, because there was no evidence in this area. Finally, they made a recommendation for research to investigate the symptoms and signs experienced by children and young people with long-term (chronic) UTI as this was also not covered by the evidence.

How the recommendations might affect practice

The 2022 recommendations are unlikely to substantially change practice because the diagnostic pathway remains the same, although some of the symptoms and signs suggesting a UTI have changed. The absence of a recommendation for any diagnostic algorithm combining symptoms and signs, means that there will be little impact on clinical resources or training.

The committee believed the 2017 recommendation would provide concise and clear guidance for healthcare professionals and more efficient diagnosis for babies under 3 months.

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Why the committee made the recommendations

Evidence showed that a positive urine dipstick test for leukocyte esterase or nitrite in children 3 months or older but younger than 3 years, greatly increases the likelihood of a positive urine culture. Sending only positive samples for culture offered a better balance of benefits and costs for these children than prescribing antibiotics and urine culture for all children. In children aged 3 months or older but younger than 3 years, symptoms are easier to identify, and antibiotics should only be started if a dipstick test is positive for either or both leukocyte esterase or nitrite. Children in this age group with a positive dipstick test should also have a urine sample sent for culture.

How the recommendations might affect practice

Recommending dipstick testing in babies and children aged 3 months or older but younger than 3 years clarifies the role of dipstick testing in this age group and encourages immediate diagnosis and treatment in primary care. The committee believe the new recommendations will provide concise and clear guidance for healthcare professionals and more efficient diagnosis. The recommendations will also be cost saving and reduce burden on laboratories by reducing the number of urine samples sent for culture.

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