Febrile infants and lumbar punctures: unravelling the evidence

Abstract

Scarfone et al published a retrospective study that identified the incidence of bacterial meningitis in 1188 febrile infants aged 29-56 days of age undergoing sepsis screening. 1 A secondary outcome was to determine whether those infants with bacterial meningitis met "low-risk" criteria. Forty (3.4%) infants had "contaminant" cerebrospinal fluid (CSF) cultures. One infant (0.08%) was diagnosed with bacterial meningitis with positive CSF culture. Analysis of 401 infants showed that 45.6% met low-risk criteria. Of the contaminant CSF culture results, 9 were found in the low-risk group. Based on these results, the authors concluded that no cases of bacterial meningitis would have been missed had a lumbar puncture not been performed in those meeting low-risk criteria. However, important data such as CSF cell counts and whether patients developed other features of bacterial meningitis later in admission were not included. Data regarding when CSF was obtained in relation to antibiotic therapy also was not included. This would have been useful in better validating their conclusion, as diagnoses of bacterial meningitis could have been missed if based primarily on culture results in infants who received antibiotics before lumbar puncture. This may have affected the overall detected incidence of bacterial meningitis. Finally, there was a lack of direct comparison between high-and low-risk groups, which would have been useful to include. The authors have highlighted a common pediatric issue, acknowledging the need for further research into the use of lumbar punctures in this age group. However, without clarification, the paper does not appear to provide sufficiently strong evidence to induce a paradigm shift in current management of this population group.