Defining complicated urinary tract infection and route of antibiotics in children presenting to the emergency department: a cohort study using the Melbourne RUPERT clinical score.

Objectives: Most children with uncomplicated urinary tract infections (UTI) can be managed with oral antibiotics. However, identifying those likely to fail oral and need intravenous antibiotics due to complicating features at presentation is challenging. We aimed to derive, validate and test a score to guide initial antibiotic route.

Design: This cohort study enrolled children both prospectively and retrospectively. Patients were divided into two groups based on whether they received intravenous or oral antibiotics after 24 hours, including those who switched between routes. Children diagnosed with confirmed UTI were used to derive then validate the score, comparing complicating clinical features between the two groups. Combinations of significantly differentiating features generated receiver operating characteristic curves and the optimal cut-off for intravenous antibiotic use was selected.

Setting: The emergency department of a tertiary paediatric hospital.

Participants: All children aged 3 months-17 years with suspected UTI were eligible, and were included if they fulfilled the diagnostic criteria for UTI.

Outcome Measures: The effectiveness of the derived clinical score to differentiate patients at presentation who had complicated UTI requiring ongoing intravenous antibiotics.

Results: There were 1240 patients, of whom 167 children aged 12 months-11 years with confirmed UTI comprised the derivation cohort. The combination of features that performed optimally (area under curve 0.85, 95% CI 0.79 to 0.91) were: rigors, urological abnormality, fever (≥38°C), emesis, recurrent (≥3) UTI, tachycardia: the RUPERT score (1 point each, maximum 6). A score ≥3 accurately classified route of antibiotics after 24 hours for 80% patients (sensitivity 77%, specificity 81%). For the 168 patients in the validation cohort, the score accurately classified 76% (sensitivity 67%, specificity 78%). The score tested well in 'probable' UTI and adolescents, and less well in infants.

Conclusion: The Melbourne RUPERT score provides the first standardised, easy-to-use score to aid clinicians in deciding route of antibiotics for more complicated UTI in children. It now needs prospective validation.