What is Encephalitis?

Encephalitis is a rare disease that causes swelling of the brain. It most often occurs before age one, and the source is usually viral. The majority of cases are caused by the herpes simplex virus, but it can also come from a host of viral maladies including chickenpox, measles, mumps and other childhood diseases.

Immunizations have reduced the risk, but it can also be caused by several other viruses including West Nile. Bacteria, parasites, cancer and allergies to immunizations are also sources of encephalitis. The very young and the elderly are at greatest risk for experiencing severe symptoms. In rare instances, it can be fatal.

What are the Symptoms of Encephalitis?

The symptoms of encephalitis vary according to the severity of the illness. It can begin with cold or flu-like symptoms. Some experience no signs at all.

Mild symptoms include

  • Head pain
  • Fever
  • Achiness in the muscles and/or joints
  • Lethargy

Serious symptoms include

  • Disorientation, anxiety or delirium
  • Paralysis or loss of feeling in specific areas
  • Weak muscles
  • Seeing double
  • Sensitivity to odors
  • Hearing problems
  • Speech difficulties
  • Unconsciousness

Infants and children may experience other symptoms include

  • Bulging fontanelle (soft spot)
  • Queasiness
  • Vomiting
  • Body rigidity
  • Continuous crying
  • Lack of appetite
  • Fussiness

Encephalitis Causes

The cause of encephalitis is generally a viral infection. In some cases, the source of the infection is not known. In some patients, the source isn’t a virus and the cause isn’t fully understood. There are also bacterial infections that can cause this disease, as well as noninfectious inflammatory conditions that lead to it.

Primary encephalitis is caused by an infection in the brain caused by a virus or another infectious agent. The infection of the brain may be spread throughout or it may be concentrated in one region of the brain. This type of encephalitis can also be caused by a reactivation of a previous viral illness. Secondary encephalitis is caused by an infection that is met by a faulty immune system. When the infectious agent spreads through the body, the immune system in these cases attacks healthy brain cells instead of the infection. Infectious agents that can cause encephalitis include herpes simplex virus types 1 and 2, enteroviruses, mosquito-borne viruses, tick-borne viruses, the rabies virus and many childhood infections.

How is Encephalitis Treated?

It is important to seek immediate professional medical care for infants and kids with symptoms of encephalitis. Treatment for confirmed cases vary according to severity of symptoms.

Mild symptoms treatment

  • Rest
  • Increased fluid intake
  • NSAIDs (naproxen sodium, ibuprofen) to relieve inflammation, fever and pain

Serious symptoms treatment

  • Intravenous antiviral medication
  • Respiratory assistance and therapy
  • IV fluids to restore and maintain hydration
  • Anti-inflammatory medication to decrease brain swelling
  • Anti-seizure medications (Dilantin)

Follow-up therapies include

  • Physical therapy
  • Occupational therapy
  • Psychiatric therapy
  • Speech therapy

Encephalitis Prevention

There has been considerable research on encephalitis, and much progress has been made toward preventing this disease. There were may infections that caused this disease that have been largely eradicated through vaccinations. Diseases like measles, rubella, mumps and smallpox are rare or eradicated today because of vaccines. To avoid encephalitis, get the recommended vaccinations and ensure that your children receive the available vaccinations that are given on the standard vaccine schedule for children. If you travel to places where certain infections are more likely, get vaccinations for those diseases before traveling. Avoid getting tick and mosquito bites to prevent the diseases they carry. Use bug spray when outdoors and check yourself thoroughly for ticks after spending time in the woods. Avoid dense vegetation that could harbor ticks.

Last Reviewed:
September 20, 2016
Last Updated:
December 19, 2017