Infectious Meningitis and Encephalitis

The clinician who is evaluating a patient with a suspected central nervous system infection often faces a large differential diagnosis. There are several signs, symptoms, geographical clues, and diagnostic testing, such as cerebrospinal fluid abnormalities and magnetic resonance imaging abnormalities, which can be helpful in identifying the etiological agent. By taking a systematic approach, one can often identify life threatening, common, and/or treatable etiologies. Here the authors describe some of the pearls and pitfalls in diagnosing and treating acute infectious meningitis and encephalitis.