In adults with suspected meningitis before neuroimaging, empiric regimen is:

• A. Dexamethasone alone
• B. Vancomycin plus a third-generation cephalosporin; add ampicillin if risk for Listeria
• C. Ceftriaxone alone
• D. Acyclovir alone

Answer: (B)

In suspected bacterial meningitis, starting broad-spectrum antibiotics right away is essential because delays worsen outcomes, and you don’t want to wait for imaging to treat. The goal is to cover the usual pathogens quickly, including those that are harder to treat.

The best empiric regimen combines vancomycin with a third-generation cephalosporin to cover the main bacteria: vancomycin guards against penicillin-resistant Streptococcus pneumoniae, while the cephalosporin (like ceftriaxone or cefotaxime) covers Neisseria meningitidis and many pneumococcal strains. Ampicillin should be added in patients with risk for Listeria monocytogenes (for example, older adults or those with weakened immune systems). This combination thus provides broad coverage for the common meningitis pathogens and accounts for Listeria when indicated.

Dexamethasone alone does not treat infection, and ceftriaxone alone would miss Listeria in at-risk patients. Acyclovir alone targets viral etiologies and is not appropriate as monotherapy for bacterial meningitis.