Meningitis, encephalitis, and beyond: A practical intensive care unit guide to severe central nervous system infections

Infections of the central nervous system can require immediate admission to an intensive care unit (ICU) because of initial severe neurologic presentation or systemic complications or may be encountered during the course of a hospital stay because of secondary complications. Brain infections include community-acquired or healthcare-associated meningitis, ventriculitis, encephalitis, and brain abscesses, which share specific clinical features but have different pathophysiology, risk factors, and outcomes. In this review, we will provide a practice-based overview of severe presentations of brain infections as encountered by the intensivist, focusing on early decision-making, sequence of diagnostic and management decisions, and encountered complications. We illustrate the review with case examples to offer real-life illustration of challenging decision-points. Key take-home points include understanding the first-hour priorities for de novo presentation of meningitis and encephalitis with focus on early initiation of antimicrobial treatment; awareness of limitations in cerebrospinal fluid (CSF)-based diagnostics for early encephalitis and in healthcare-associated meningitis and ventriculitis, and the importance of expedited, non-CSF-based diagnostic approach to brain abscesses.