by Rosalyn Carson-DeWitt, MD
Encephalitis is inflammation of the brain. The inflammation may be in the whole brain or just parts of the brain. The swelling can stop the brain from working properly, increase pressure in the skull, and damage brain tissue.
Encephalitis is often caused by a viral infection. 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 viral encephalitis include:
Certain cancers can overstimulate the immune system. This can increase the risk of encephalitis.
The symptoms may range from mild to severe. Severe encephalitis can lead to permanent brain damage and death.
Milder symptoms include:
More severe symptoms may include:
You will be asked about your symptoms and medical history. A physical exam will be done.
To look for signs of infection your bodily fluids may be tested. This can be done with:
A brain biopsy may also be done to look for problems in the brain tissue.
Images may be taken of your head to look for swelling or damage. This can be done with:
Your brain's electrical activity may be tested. This can be done with an electroencephalogram (EEG).
There are very few treatments for viruses, they simply have to run their course. Most treatment will focus on supporting the body until the virus has passed. Treatment will be based on individual needs but may include:
To help reduce your chance of encephalitis:
The Encephalitis Society
National Institute of Neurological Disorders and Stroke
Canadian Neurological Sciences Federation
Herpes simplex encephalitis. EBSCO DynaMed Plus website. Available at:http://www.dynamed.... Updated February 14, 2015. Accessed September 23, 2016.
Eastern equine encephalitis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.... Updated February 4, 2016. Accessed September 23, 2016.
Mann AP, Grebenciucova E, Lukas RV. Anti-N-methyl-D-aspartate-receptor encephalitis: diagnosis, optimal management, and challenges. Ther Clin Risk Manag. 2014;10:517-525.
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NINDS meningitis and encephalitis information page. National Institute of Neurologic Disorders and Stroke website. Available at:
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Updated April 16, 2014. Accessed September 23, 2014.
West Nile virus infection. EBSCO DynaMed Plus website. Available at: http://www.dynamed.... Updated July 21, 2016. Accessed September 23, 2016.
10/1/2013 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T115142/Mosquito-avoidance. Reimer LJ, Thomsen EK, Tisch DJ, et al. Insecticidal bed nets and filariasis transmission in Papua New Guinea. N Eng J Med. 2013;369(8):745-753.
Last reviewed September 2016 by Rimas Lukas, MD
Last Updated: 3/13/2017
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