Normative cerebrospinal fluid profiles in febrile infants

Objective: To describe the cerebrospinal fluid (CSF) profiles of febrile infants aged 1 to 90 days with negative bacterial culture test results and negative results for enteroviruses with polymerase chain reaction. Study design: Statistical analysis of a retrospective cohort. Results: CSF profiles from 823 infants with negative test results for infection were analyzed. For 677 infants with atraumatic lumbar punctures (red blood cell [RBC] count <1000/mm ³), the mean and median CSF white blood cell (WBC) counts were 4.3/mm³ and 3.0/mm³, respectively, with a range from 0 to 12/mm³. Mean CSF WBC counts (6.1/mm³ versus 3.1/mm ³ and 3.0/mm³) and protein levels (75.4 mg/dL versus 58.9 mg/dL and 39.2 mg/dL) were higher in the first month compared with months 2 and 3, respectively (P < .001 for all). CSF glucose levels were lower in the first month compared with month 3 (45.3 mg/dL versus 48.0 mg/dL and 57.7 mg/dL; P < .001). Increasing RBC counts were statistically associated with increasing WBC counts (P < .001). However, the contribution of RBC < 10 000/mm³ was small, and the reference range for WBC in uninfected infants with traumatic lumbar punctures was 0 to 16/mm³. Conclusion: CSF WBC counts in febrile infants without evidencse of bacterial or enteroviral infection, even in those with traumatic lumbar puncture, are lower than reported in pediatric references.