Acute encephalitis is a serious form of neurological disease caused by inflammation of the brain parenchyma. It is generally characterized by the acute onset of fever, altered mental status, new onset of focal neurological symptoms, and generalized or focal seizures. It can develop with various etiologies, but viral infection and autoimmune disorders are the most common. Causes of acute viral encephalitis include herpes simplex virus, other herpes viruses, adenoviruses, influenza A.