Treatment of Infectious Meningitis and Encephalitis in the Neurocritical Care Unit

In this chapter, we discuss meningitis and encephalitis, which can be diagnostically challenging for practitioners. Timely diagnosis and treatment is crucial, as many of these infections are associated with high morbidity and mortality. Meningitis may be caused by various pathogens each associated with specific imaging findings, treatments, and complications. Encephalitis falls within the spectrum of central nervous system infections, like meningitis, but is distinguished by the involvement of brain parenchyma. Organisms are usually identified for cases of meningitis, but pathogens are less often identified for encephalitides though typically are viral. Of the viral encephalitides, one of the most important to consider is herpes simplex virus (HSV) encephalitis because it is the most common and has a high mortality. Additionally, HSV encephalitis is the only viral encephalitis with an evidence-based treatment, acyclovir. In recent years, recognition of autoimmune encephalitides has increased substantially, along with recommendations for their treatment with immunosuppressive agents. Other etiologies are important to identify as they have prognostic significance; however, treatment is often supportive. Patients with central nervous system infections often require admission to the intensive care unit for mechanical ventilation, close monitoring of neurologic status, or management of infection-related complications.