Viral Encephalitis

Viral encephalitis is an infection of the brain by a virus. It usually is accompanied by an infection of the lining of the brain and spinal cord (meningitis). It is sometimes called meningoencephalitis.


Viral encephalitis is caused by many viruses. Some of these viruses can be passed between humans. Others come from contact with infected animals or insects. A bite from a mosquito or tick can pass viral encephalitis.


Symptoms of viral encephalitis vary. Common signs include:

  • Fever.

  • Muscle aches.

  • Headache or backache.

  • Eye pain from lights.

  • Stiff neck.

  • Confusion.

  • Unusual drowsiness

  • Nausea and vomiting.

  • Difficulty speaking.

  • Irritability.

  • Clumsiness.

  • Convulsions.


Blood and spinal fluid are tested. Spinal fluid is tested by collecting a sample during a spinal tap. Sometimes imaging studies of the brain are done. It can take a while to figure out which virus is causing the infection.


Some of the viruses that cause encephalitis can be treated with anti-viral medications. Other viruses have no specific treatment. Except in very mild cases, hospitalization is often needed to treat and watch for complications. Sometimes antibiotics are given for a day or two. This is to be sure that the infection is not due to a bacterial germ. Intravenous fluids can be given if:

  • Vomiting has led to dehydration.

  • You cannot keep fluids down.

Medications can treat convulsions. Fever and pain relievers can be helpful.


  • Treatment can be done at home for mild cases or after hospitalization. It is important for caregivers at home to wash their hands after handling the patient.

  • Give pain and fever relievers as needed.

  • Give plenty of fluids if there is nausea and vomiting.

  • Bed rest and quiet are best. Keep the room dark or lit dimly for sensitivity to light.


  • New symptoms develop.

  • Fever returns after being gone for a day or two.


  • Convulsions occur in the arms, legs, or elsewhere. Convulsions can be uncontrolled stiffening, twitching or jerking.

  • The patient cannot wake up.

  • There is weakness in an arm or leg.

  • There is memory loss.

  • Signs of dehydration develop including:

  • Increased thirst.

  • Weakness.

  • Confusion.

  • Drowsiness.

  • Dizziness.

  • Fainting.

  • Decreased urination.

  • Decreased activity (child).

  • Irritability, fussiness (child).


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.