A modified Philadelphia criterion for the risk stratification of febrile infants with invasive bacterial infection had a high sensitivity without routine cerebrospinal fluid (CSF) testing, according to data published in Pediatrics.
Study investigators performed a case-control study on febrile infants who were aged ≤60 days presenting at one of nine emergency departments between 2011 and 2016. They enrolled 135 infants with invasive bacterial infection (118 who had bacteremia without meningitis and 17 with bacterial meningitis) and 249 controls matched by site and date of visit. The low-risk components of the modified Philadelphia criteria were: aged >28 days, previously healthy, no skin or soft tissue infection, normal urinalysis, a peripheral white blood cell count of ≥5000 and ≤15 000, and an immature-to-total neutrophil ratio of <0.2.
The sensitivity of the modified Philadelphia criteria was higher than the Rochester criteria (91.9% vs 81.5%; P =.01). However, specificity was lower (34.5% vs 59.8%; P <.001). The sensitivity of both criteria in 67 infants aged >28 days with invasive bacterial infection was 83.6%. None of the 11 low-risk infants had bacterial meningitis and of the 68 infants aged ≤28 days with invasive bacterial infection, 14 were low risk according to the Rochester criteria, with 2 having meningitis.
The study investigators noted several limitations including that data was collected through a medical record review and therefore clinical variables were not accurately documented. They were also unable to calculate positive or negative predictive values for either criterion because not all febrile infants at the study sites were included. There was also a low prevalence of bacterial meningitis in the sample. Finally, there was no guarantee that a control infant wasn’t diagnosed with invasive bacterial infection at a non-participating hospital at a later date and the sample may not be generalizable beyond the participating emergency departments.
Study investigators concluded that while neither criteria contain routine CSF testing, the modified Philadelphia were highly sensitive in risk stratification of non-ill appearing febrile infants with bacteremia. They recommended that a prospective study is now required to confirm the safety of routinely omitting CSF testing in low-risk febrile infants aged <28 days.
Aronson PL, Wang ME, Shapiro ED, et al. Risk stratification of febrile infants ≤60 days old without routine lumbar puncture. Pediatrics. 2018;142: e20181879