Encephalitis.

Encephalitis is an infectious or inflammatory disorder of the brain that presents with fever, headache, and an altered level of consciousness. There may also be focal or multifocal neurologic deficits, and focal or generalized seizure activity. Of the infectious etiologies, herpesviruses are the most common and some of the few treatable viral causative agents of encephalitis. The etiology, clinical presentation, diagnosis, and treatment of viral encephalitis is discussed in this chapter.