Point-of-Care Guides

Diagnosis of Urinary Tract Infections in Children

 

Am Fam Physician. 2018 Feb 15;97(4):273-274.

Author disclosure: No relevant financial affiliations.

Clinical Question

In which acutely ill children should urinary tract infection (UTI) be suspected, prompting a urine culture?

Evidence Summary

A recent observational study found that 2.2% of acutely ill children younger than five years met criteria for a UTI when their urine was cultured. However, in the same study, overall clinician impression that a UTI was present (fairly to very certain) identified only 28 out of 60 children with a microbiologically confirmed UTI.1 Because obtaining a urine specimen from all acutely ill children would be impractical, time-consuming, and potentially invasive, and would increase costs, a number of clinical decision rules have been developed and validated to identify children at increased risk of UTI, in whom a urine culture should be obtained.

A prospective study of 15,781 children younger than five years with febrile illness developed a multivariate model to identify children with UTI.2 However, this model is complex, with 26 variables, and is not practical for outpatient primary care practice. It also included patients from emergency departments, where there is likely a different spectrum of disease than in routine primary care practice. Another study developed a simpler model that included only five variables, with one point for each variable (age younger than 12 months, temperature greater than 102.2°F [39°C], white race, fever for two or more days, and no other potential source of fever).3 Those with a score of 2 or higher had a 6.4% likelihood of UTI, compared with 0.8% in those with a score less than 2. In a prospective case-control validation study of children in the emergency department, a score of 3 or higher was a better cutoff.4

Most recently, the UK Diagnosis of Urinary Tract Infection in Young Children (DUTY) study enrolled children five years and younger presenting with acute illness characterized by at least one systemic symptom (fever, vomiting, lethargy/malaise, irritability, poor feeding, or failure to thrive) and one symptom suggestive of UTI (abdominal pain, jaundice if younger than three months, hematuria, offensive urine odor, cloudy urine, loin pain, urinary frequency, apparent pain on passing urine, or changes in continence).1  All patients underwent a standardized assessment of signs and symptoms, and 2,740 were able to provide a clean-catch urine sample for culture as a reference standard. The researchers developed two clinical decision rules (Table 1).1 One is based on signs and symptoms alone to determine whether a urine sample should be obtained, and one incorporates dipstick urine test results and determines whether an antibiotic is warranted. Because there were only 60 children with UTIs out of the 2,740 who provided a clean-catch urine sample, split sample validation was not possible; bootstrap validation was used to verify the predictive accuracy of the model. The signs and symptoms model had an area under the receiver operating characteristic curve (AUROCC) of 0.88, and the expanded model that adds three variables from dipstick urine testing (hematuria, nitrite, and leukocyte esterase) had an AUROCC of 0.93. Both of these models are significantly more accurate than overall clinical impression that a UTI is present, which had an AUROCC of 0.77.

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TABLE 1.

The DUTY Clinical Decision Rules

Signs and symptoms model

Signs, symptoms, and dipstick model



Clinical characteristic

Points

Clinical characteristic

Points



Pain/crying when passing urine

2

Pain/crying when passing urine

2

Smelly urine (parental report)

2

Smelly urine (parental report)

2

Previous UTI

1

Previous UTI

1

Absence of severe cough*

2

Absence of severe cough*

2

Severe illness present†

2

Severe illness present†

2

Total:

____

Dipstick urine analysis positive for:

Leukocytes

2

Nitrites

3

Blood

1

Total:

____

Total points

UTI diagnoses/ total patients (%)

LR‡

Total points

UTI diagnoses/ total patients (%)

LR‡



0 to 2

9/2,003 (0.45%)

0.20

0 to 5

13/2,444 (0.53%)

0.24

3 or 4

20/562 (3.6%)

1.6

6 to 8

18/240 (7.5%)

3.6

5 or more

31/175 (17.7%)

9.6

9 or more

29/56 (51.8%)

48.0


DUTY = Diagnosis of Urinary Tract Infection in Young Children; LR = likelihood ratio; UTI = urinary tract infection.

*—Parents were given four levels to choose from for severity of cough: no problem, slight problem, moderate problem, or severe problem.

†—Defined as a score of 6 or more on the clinician global illness severity scale, with a range of 0 (child completely well) to 10 (child extremely unwell).

‡—An LR less than 1 reduces the likelihood of UTI, and an LR more than 1 increases the likelihood of UTI.

Information from reference 1.

TABLE 1.

The DUTY Clinical Decision Rules

Signs and symptoms model

Signs, symptoms, and dipstick model



Clinical characteristic

Points

Clinical characteristic

Points



Pain/crying when passing urine

2

Pain/crying when passing urine

2

Smelly urine (parental report)

2

Smelly urine (parental report)

2

Previous UTI

1

Previous UTI

1

Absence of

Address correspondence to Mark H. Ebell, MD, MS, at ebell@uga.edu. Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.

References

show all references

1. Hay AD, Sterne JA, Hood K, et al. Improving the diagnosis and treatment of urinary tract infection in young children in primary care: results from the DUTY prospective diagnostic cohort study. Ann Fam Med. 2016;14(4):325–336....

2. Craig JC, Williams GJ, Jones M, et al. The accuracy of clinical symptoms and signs for the diagnosis of serious bacterial infection in young febrile children: prospective cohort study of 15 781 febrile illnesses. BMJ. 2010;340:c1594.

3. Gorelick MH, Shaw KN. Clinical decision rule to identify febrile young girls at risk for urinary tract infection. Arch Pediatr Adolesc Med. 2000;154(4):386–390.

4. Gorelick MH, Hoberman A, Kearney D, Wald E, Shaw KN. Validation of a decision rule identifying febrile young girls at high risk for urinary tract infection. Pediatr Emerg Care. 2003;19(3):162–164.

This guide is one in a series that offers evidence-based tools to assist family physicians in improving their decision-making at the point of care.

This series is coordinated by Mark H. Ebell, MD, MS, Deputy Editor for Evidence-Based Medicine.

A collection of Point-of-Care Guides published in AFP is available at http://www.aafp.org/afp/poc.

 

 

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