Which empiric regimen is commonly used for suspected meningitis in adults in the emergency department?

• A. Vancomycin + Ceftriaxone + Dexamethasone
• B. Vancomycin + Cefepime + Dexamethasone
• C. Ceftriaxone + Vancomycin + Dexamethasone
• D. Ceftriaxone alone

Answer: (C)

When suspected bacterial meningitis in adults, the aim is to cover the most likely pathogens quickly with antibiotics that penetrate the CSF, while also reducing inflammatory injury. Ceftriaxone provides strong coverage against Neisseria meningitidis and Streptococcus pneumoniae, including many penicillin-susceptible strains. Vancomycin adds protection against penicillin-resistant Streptococcus pneumoniae, which is a known concern and can lead to treatment failure if not covered. Dexamethasone is given at or just before the first dose of antibiotics to blunt the inflammatory response, especially in pneumococcal meningitis, and it has been shown to improve neurologic outcomes when started promptly.

Choosing ceftriaxone alone would miss resistant pneumococci, and adding vancomycin ensures broader, more reliable coverage of the key bacteria responsible for meningitis in adults. While broader agents like cefepime exist, the conventional ED empiric regimen for community-acquired meningitis prioritizes ceftriaxone plus vancomycin with dexamethasone for targeted early therapy. In older or immunocompromised patients, ampicillin would be added to cover Listeria, but that nuance is separate from the standard initial regimen.