Serious Bacterial Infections in Young Febrile Infants With Positive Urinalysis Results

Area of Science:

• Pediatrics
• Infectious Diseases
• Clinical Decision Making

Background:

• Febrile infants younger than 60 days with positive urinalysis (UA) results present a clinical challenge regarding the necessity of lumbar puncture (LP) to rule out serious bacterial infections.
• Current guidelines do not uniformly address the risk stratification for bacterial meningitis and bacteremia in this specific age and UA-positive subgroup.

Purpose of the Study:

• To determine the prevalence of bacteremia and bacterial meningitis in febrile infants up to 60 days old with positive urinalysis results.
• To assess if routine lumbar punctures are necessary for febrile infants aged 29-60 days with positive UA results.

Main Methods:

• Secondary analysis of a prospective observational study including noncritical febrile infants (≤60 days) from 2011-2019.
• Data included temperature, blood cultures, and urinalysis (UA) results. Infants were stratified by age (≤28 days vs. 29-60 days) and UA status.
• Prevalence of bacteremia and bacterial meningitis was compared between infants with positive and negative UA results, and in low-risk infants based on specific blood thresholds.

Main Results:

• Among 7180 infants, 15.2% had positive UA results. Bacteremia risk was higher in infants with positive UA (5.8%) versus negative UA (1.1%).
• No significant difference in bacterial meningitis prevalence was observed in infants ≤28 days with positive vs. negative UA (approx. 1%).
• Crucially, no cases of bacterial meningitis occurred in infants aged 29-60 days with positive UA results. Furthermore, no bacteremia or meningitis was found in low-risk infants (defined by specific blood markers) with positive UA.

Conclusions:

• Febrile infants aged 29-60 days with positive urinalysis results and low-risk blood work do not appear to require routine lumbar punctures for bacterial meningitis evaluation.
• These findings support refining clinical decision-making algorithms for managing febrile infants with positive UA results, potentially reducing unnecessary invasive procedures.
• The study highlights the importance of considering specific clinical and laboratory parameters for targeted diagnostic workups in young febrile infants.