Antipsychotic drugs may be needed for a short time period if behavior alternations are present. Given the possibility of complications developing from viral encephalitis, an interdisciplinary team consisting of the clinicians, therapists, rehabilitation specialists, and speech therapists is important in order to help patients. Prognosis
If treated, most individuals recover from viral encephalitis without long-term problems related to the illness. Mortality rates vary for those who do not receive treatment, for example being about 70% for herpes encephalitis but low for the La Crosse virus. Individuals who remain symptomatic after initial infection may have difficulty concentrating, behavior or speech disorders, or memory loss. Rarely, individuals may remain in a persistent vegetative state. The most common long-term complication of viral encephalitis is seizures that may occur in 10% to 20% of patients over several decades. These seizures are resistant to medical therapy. However, individuals who have unilateral mesial temporal lobe seizures after viral encephalitis have good results following neurosurgery. Prognoses related to specific viruses include:
For Eastern equine encephalitis, some children may experience seizures, severe intellectual disability, and various forms of paralysis. For Japanese encephalitis, extrapyramidal symptoms relating to motor function may remain. For St. Louis encephalitis, low blood sodium level and excess, unsuppressable release of antidiuretic hormone
For Western equine encephalitis, some children may experience seizures and behavioral changes.
Treatment
Treatment of viral encephalitis is primarily supportive with intravenous antiviral therapy due to there being no specific medical therapy for most viral infections involving the central nervous system. Individuals may require intensive care for frequent neurological exams or respiratory support, and treatment for electrolyte disturbance, autonomic disregulation, and renal and hepatic dysfunction, as well as for seizures and non-compulsive status epilepticus.A very specific exception is herpes simplex virus (HSV) encephalitis, which can be treated with acyclovir for 2 to 3 weeks if it is provided early enough. Acyclovir significant decreases morbidity and mortality of HSV encephalitis and limits the long-term behavioral and cognitive impairments that occur with illness. As such, and because HSV is the most common cause of viral encephalitis, acyclovir is often administered as soon as possible to all patients suspected of having viral encephalitis even if the exact viral origin is not yet known. Viral resistance to acyclovir rarely occurs, primarily among the immunocompromised, in which case foscarnet should be used. Although not as effective, nucleoside analogs are used for other herpesviruses as well, such as acyclovir, with possible adjunctive corticosteroids for immunocompetent individuals, for varicella-zoster virus encephalitis and a combination of ganciclovir and foscarnet for cytomegalovirus encephalitis.Serial intracranial pressure (ICP) is important to monitor as elevated ICP is associated with poor prognosis. Elevated ICP can be relieved with steroids and mannitol, though there is limited data of the efficacy of such treatment with regards to viral encephalitis. Seizures can be managed with valproic acid or phenytoin. Status epilepticus may required benzodiazepines.