Encephalitis is a swelling (inflammation) of the brain. It is usually caused by a virus. The normal blood flow to the brain changes. This can cause confusion, a high fever, and a severe headache. You also may be sleepy and sensitive to light. And you may have nausea and a stiff neck and back. In more serious cases, a person may have seizures or tremors.

Encephalitis is not common, but it can be deadly if it's not treated right away.

Encephalitis is treated in the hospital. Treatment may include antiviral medicine. It can help your body get rid of the virus. It also may make symptoms less severe. You will also get supportive care. This helps to ease your symptoms and allow your body to heal on its own. Some people may need physical therapy or occupational therapy.