Cerebrospinal Fluid Cell (CSF) Counts in Infants < 60 Days of Age. 1325

INTRODUCTION: The lumbar puncture is a common diagnostic test performed to evaluate infants under 2 months of age who are exhibiting signs of either generalized or central nervous system (CNS) infection. However, there are few data sets of “normal” white blood cell (WBC) counts in the CSF of infants without CNS infection. METHODS: A retrospective chart review was performed of patients < 60 days of age seen in the Children's Hospital of Pittsburgh Emergency Department from March 1995 through February 1996 who had a lumbar puncture performed for the evaluation of possible sepsis/meningitis. Patients were excluded if CSF red blood cell (RBC) counts were > 1000 cells/mm³, if viral or bacterial cultures of CSF demonstrated a pathogen, or if the CSF WBC count > 100 cells/mm³. (Patients in the last group were presumed to have viral meningitis even though a virus was not isolated from the CSF). RESULTS: There were 363 charts available for review, 69 were excluded for CSF RBC > 1000 cells/mm³, 3 for positive viral culture, and 12 patients without a positive bacterial or viral culture but with CSF WBC count > 100 cells/mm³. 55% of the patients were male. Results are shown in the table. 75% of the patients had CSF WBC less than 6.0 and 95% had values less than 18 cells/mm³. CONCLUSION: A knowledge of normal WBC values in the CSF of infants less than 2 months of age is necessary to interpret clinical data. The imprecision of diagnosing viral infection of the CNS confounds the collection of normative data.

Table 1