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/mm3, 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% of concurrent comorbid disease, and 15% had identified immunocompromising conditions. The reported examination findings were diverse, with 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.