[Encephalitis in adults].

Encephalitis is the result of focal or global inflammation of the brain caused by invasion of the brain parenchyma by viruses, bacteria, parasites or fungi. In addition, postinfectious encephalitis may result from immunological processes as a consequence of preceding viral infections such as measles. For most forms of viral encephalitis no specific therapy is available. Herpes simplex encephalitis may be diagnosed using modern laboratory techniques for detection of viral DNA without the need for brain biopsy. Herpes simplex encephalitis responds well to treatment with acyclovir, as does encephalitis caused by varicella-zoster virus, which typically occurs following cutaneous herpes zoster involving dermatomal distributions of the trigeminal nerve. In immunocompromised hosts many etiologies of encephalitis need to be considered. It is important to arrive at a precise diagnosis in order to choose appropriate therapeutic agents directed toward treatable pathogens such as Toxoplasma gondii and cytomegalovirus.