Bacterial meningitis.

With nearly 8,000 cases in the United States per year, and 2,000 deaths annually, bacterial meningitis continues to be a significant source of morbidity and mortality. The principal pathogens are Neisseria meningitidis, Streptococcus pneumoniae, group B streptococci, and Hemophilus influenzae. In immunocompromised patients, Listeria monocytogenes is also an important pathogen. Rapid identification and evaluation of the patient with bacterial meningitis and prompt initiation of antibiotics are the cornerstones of therapy. Except in the rare patient with papilledema, focal neurologic symptoms, or a seizure, a lumbar puncture should be performed without delay, and antibiotic therapy should be administered promptly. Patients without a readily identifiable source of infection should be treated empirically with intravenous ceftriaxone. Ampicillin should also be administered in populations at increased risk for L. monocytogenes. The risk of meningitis in some populations can be reduced by administration of vaccines against selected pathogens such as N. meningitidis, S. pneumoniae, and H. influenzae.