Role of empiric parenteral antibiotics prior to lumbar puncture in suspected bacterial meningitis: state of the art.

The performance of lumbar puncture (LP) in patients with suspected meningitis is often delayed if, for example, the clinical presentation suggests a need for prior computed tomographic (CT) scan or if patients are initially examined at settings with limited clinical facilities. The role of empiric parenteral antibiotic therapy prior to LP under these circumstances has not been critically analyzed. Review of the literature suggests that in cases of bacterial meningitis (1) the existing data are inadequate to assess the effect of a short delay of therapy on mortality and morbidity; (2) a short period of antibiotic therapy prior to LP does not change cerebrospinal fluid (CSF) white blood cell count, protein, or glucose; (3) the yield of CSF gram stain and culture may be somewhat reduced by a short period of antibiotic therapy, but these tests often remain positive; and (4) adjunctive tests, including blood cultures and CSF antigen tests, can often independently identify the bacterial meningopathogen. The available evidence suggests that if bacterial meningitis is suspected and LP must be delayed, intravenous antibiotics are warranted before CSF is obtained.