ICU · Neurocritical Care

Meningitis and encephalitis in the ICU

Also known as Bacterial meningitis · Viral encephalitis · Herpes simplex encephalitis (HSE) · Empiric meningitis treatment · CSF analysis

Bacterial meningitis and viral encephalitis are neurological emergencies. Bacterial meningitis: fever, headache, neck stiffness, altered mental status (the classic triad in only 44 percent of cases, though 95 percent have at least two of the four features). Empiric therapy within the hour: dexamethasone 10 mg IV before or with the first antibiotic dose, then high-dose ceftriaxone plus vancomycin (add ampicillin for older or immunocompromised patients — Listeria). Viral encephalitis: HSV is the most common treatable cause — acyclovir 10 mg/kg IV every 8 hours while awaiting PCR. LP: send CSF for cell count, differential, protein, glucose with paired serum glucose, Gram stain, culture, viral PCR (HSV, VZV, enterovirus). NEVER delay antibiotics for LP or CT. Adjunctive dexamethasone cut unfavourable outcome (RR 0.59) and death (RR 0.48) in the landmark trial and reduces hearing loss.

Checked against its sources on 13 Sept 2026