ICU · Neurocritical care / infectious

CNS Infections — Meningitis, Encephalitis & Brain Abscess

Also known as Bacterial meningitis · Viral encephalitis · HSV encephalitis · Brain abscess · CNS infection · Ceftriaxone · Acyclovir · Dexamethasone meningitis · Lumbar puncture · Cerebrospinal fluid · CSF analysis · Door-to-antibiotic

The CNS infections in the ICU are the bacterial meningitis, the viral encephalitis, and the brain abscess. The bacterial meningitis presents with the fever, the neck stiffness, and the altered consciousness (the classic triad — present together in only 44 per cent, but 95 per cent have at least two of the four features: headache, fever, neck stiffness, altered mental status). The CSF shows the raised opening pressure, the cloudy appearance, the neutrophil predominance, the raised protein, and the low glucose. The empirical therapy is high-dose ceftriaxone (75–100 mg/kg/day per the French adult guideline) plus the vancomycin plus the dexamethasone 10 mg IV every 6 hours for 4 days (given before or with the first antibiotic dose), with the ampicillin added for the older or immunocompromised patient and the acyclovir 10 mg/kg IV every 8 hours if the HSV is suspected. The door-to-antibiotic target is under 1 hour — the antibiotics are NOT delayed for the CT or the LP. The HSV encephalitis is treated with the empirical acyclovir 10 mg/kg every 8 hours (at least 10 days; the PCR is the diagnostic test). The brain abscess complicating meningitis (1.9 per cent of episodes) is treated with the prolonged antibiotics and the neurosurgical drainage when indicated.

Checked against its sources on 2 Sept 2026