With the exception of herpes simplex and varicella-zoster encephalitis, the viral forms of encephalitis are not treatable. The primary objective is to diagnose the patient as soon as possible so they receive the right medicines to treat the symptoms. It is very important to lower fever and ease the pressure caused by swelling of the brain.

Patients with very severe encephalitis are at risk for body-wide (systemic) complications including shock, low oxygen, low blood pressure, and low sodium levels. Any potentially life-threatening complication should be addressed immediately with the appropriate treatments.
Treating Probable Causes of Encephalitis

Since it is difficult to determine the cause of encephalitis, and rapid treatment is essential, clinical guidelines recommend immediately administering intravenously the antiviral drug acyclovir without waiting to determine the cause of the illness.

Once the doctor receives results from diagnostic tests, drug treatment depends on the cause of the encephalitis. Antiviral drug treatments for specific causes of encephalitis include:

    Herpes Simplex Virus . Acyclovir is recommended.
    Varicella-Zoster Virus . Acyclovir is recommended. Ganciclovir or adjunctive corticosteroids may also be considered.
    Cytomegalovirus . Combination of ganciclovir plus foscarnet.
    Epstein-Barr Virus . Corticosteroids may be used, although risks may outweigh benefits. (Acyclovir is not recommended.)
    Human Herpesvirus 6. Ganciclovir or foscarnet are recommended for immunocompromised patients.
    Measles. Ribavirin may be considered.
    ADEM. High-dose intravenous corticosteroids.
    St. Louis Encephalitis . Interferon alfa-2a may be considered.

For bacterial meningitis, antibiotics (not antiviral drugs) are used.
Additional Treatments

Other encephalitis treatments are aimed at reducing symptoms.

    Seizures may be prevented by using oral anticonvulsant drugs.or intravenous lorazepam (Ativan).
    Sedatives may be prescribed for irritability or restlessness.
    Simple pain relievers may be used for fever and headache.
    In patients who are otherwise stable, the only other treatment measures are to keep the head elevated and monitor the patient's status.

Investigational Treatments

No specific drugs have been effective for treating arboviruses, including West Nile virus, although a number of drugs used to treat other virus infections are being investigated. They include interferon alfa 2a (Roferon-A) and other interferons.