Bacterial meningitis. Limitations of repeated lumbar puncture.

A retrospective chart review of 47 pateints with bacterial meningitis was conducted with respect to current guidelines used to define an adequate duration of antimicrobial therapy. Fifty percent (19/38) of patients had an inadequate response to therapy as defined by repeated lumbar puncture (LP) findings (ie, a cerebrospinal fluid (CSF) blood cell count greater than 50/cu mm and/or a CSF glucose value less than 45 mg/100 ml) at the end of therapy. No cases of relapse were seen. Persistent CSF abnormalities were not associated with the presence of complicating disease but were associated with prolongation of antimicrobial therapy beyond 13 days. Patients having persistent CSF abnormalities at the time antibiotics were stopped had a higher CSF blood cell count and a lower glucose value on initial lumbar puncture than those not having persistent abnormalities (P less than .001). These results emphasize the limitations of the role of repeated LP in defining an adequate duration of antimicrobial therapy.