Should we test RSV-positive infants for UTIs?
RSV-positive bronchiolitis is one of the most common reasons for hospital admission. Sometimes they spike temperatures. It is widely recognised that the rate of serious bacterial infection in these infants is low. But what about the rate of UTIs? Should we be doing urine dips on all febrile babies with bronchiolitis, or is that overkill?
This study hypothesised that UTIs in 3-12-month-old febrile, RSV-positive infants are rare.
Who was studied?
This was a retrospective study of all infants (0-12 months) admitted to a US paediatric unit between 2006 and 2012.
The inclusion criteria were:
- febrile infants
- admitted as an inpatient
- positive for rapid RSV antigen detection test or NPA
The exclusion criteria were:
- born before 36 weeks
- known urinary tract abnormalities
- previous UTIs
- known immunodeficiencies
- already give antibiotics 72 hours prior to urine sample
All patients had a urinalysis and urine culture obtained by catheterisation.
412 patients were included (57% boys, 43% girls).
What were the outcomes?
Patients were retrospectively examined for a positive urinalysis (leukocyte +/- nitrite or 5+ WCC on microscopy).
They were also assessed for the presence of UTI (growth of a single identified pathogen).
Other measured outcomes were: age, sex, race, circumcision status, maximum temp, WCC, and neutrophil count.
What did the results show?
Out of 414 infants, 6.3% had a positive urine culture.
The most common pathogen was E.coli.
Sex, race, age, peak temp, WCC or neutrophil count were not associated with an increased risk of UTI.
In infants aged 3-6 months, 7.7% had a concurrent UTI.
Circumcised boys had a reduced risk of UTI.
RSV-positive bronchiolitis is very common. When these infants become febrile, we should not discount a concurrent UTI. 6.3% of infants have a UTI as well as bronchiolitis. Don’t assume the temp is due to bronchiolitis – check the urine.
