Meningitis and Encephalitis

Abstract

Acute meningitis may be caused by a wide variety of infectious pathogens as well as by non-infectious diseases. Given its frequency and clinical impact, this chapter focuses specifically on acute bacterial meningitis. Rapid recognition of meningitis is critical to ensure timely receipt of empiric antimicrobial therapy. Encephalitis is distinguished from meningitis by the presence of abnormal brain function, which may manifest as altered mental status, motor, sensory or speech deficits, movement disorders, or seizures. The chapter presents diagnosis, epidemiology, etiology, clinical presentation, laboratory findings, other diagnostic modalities, preventive therapy and prognosis of meningitis and encephalitis. It focuses primarily on viral encephalitis in adults in the United States. There are a multitude of viral causes of encephalitis. Viruses may cause direct neuro-invasion and post-infectious autoimmune phenomenon, including anti-NMDA receptor antibody encephalitis.