by Rosalyn Carson-DeWitt, MD
Encephalitis is swelling of the brain. The swelling may involve the whole brain, or just parts of the brain. Encephalitis may just occur in individuals (sporadic) or may affect many people in a particular area (epidemic).
Encephalitis is most often caused by a viral infection. In the United States, the most common cause of sporadic encephalitis is the herpes simplex virus (HSV). Epidemic causes of encephalitis are usually mosquito or tick-borne viruses.
The most common viruses that cause encephalitis include:
Not all encephalitis is caused by a virus. Some may be due to an overreaction of the immune system.
Risk Factors TOP
Factors that may increase your chance of encephalitis include:
Newborns of mothers who have genital herpes simplex are at risk for herpes simplex encephalitis.
The symptoms may range from mild to severe. Severe symptoms can include permanent neurological damage. Encephalitis can also lead to death.
Milder symptoms include:
More severe symptoms may include:
The doctor will ask about your symptoms and medical history. A physical exam will be done.
Tests may include:
Treatment is mostly supportive. It may include:
Make sure that you and your children are vaccinated against preventable viral illnesses.
Encephalitis Information Resource
National Institute of Neurological Disorders and Stroke
Canadian Neurological Sciences Federation
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Eastern equine encephalitis. EBSCO Publishing DynaMed website. Available at: http://www.ebscohost.com/dynamed/. Updated July 13, 2012. Accessed September 20, 2012.
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Last reviewed September 2012 by Rimas Lukas, MD
Last Updated: 09/30/2012