Acute meningitis with a negative Gram's stain: Clinical and management outcomes in 171 episodes

PURPOSE: TO characterize the diagnostic spectrum and physician management decisions of patients presenting to an emergency department with an acute, community-acquired illness, cerebrospinal fluid (CSF) white blood cell count >5/mm(3), and a negative Gram's stain for bacteria. PATIENTS AND METHODS: In this retrospective cohort study over a 2-year period, symptoms, examination findings, paraclinical data, physician management, and clinical outcomes were assessed for each patient. RESULTS: One hundred sixty-eight patients (171 patient episodes) were evaluated. Almost half of the cohort presented in nonsummer months (48%); 20% had concurrent comorbid disease, and 15% had identified immunocompromising conditions. The reported examination findings were diverse, with fever (49%) and neck stiffness (39%) being the most frequent findings. The majority were hospitalized (70%), with a median stay of 4 days. Approximately one half underwent computed tomography or magnetic resonance imaging (49%), and received empiric treatment with antibiotics (52%). A diagnostic cause was established in 23%, with the majority being inherently treatable diseases (including syphilis, bacteremia, Lyme disease). Variables significantly associated with a subsequent proven diagnostic cause included: age >60 years; presence of comorbid disease (especially immunodeficiency); and presentation in winter months. CONCLUSIONS: A large proportion of patients presenting with acute meningitis and a negative CSF Gram's stain undergo hospitalization, noninvasive cranial imaging, and receive empiric antibiotic therapy. Better clinical guidelines are needed to identify the diagnostic and management decisions that benefit patient outcome.