Inflammation of the brain (regardless of cause).
- Acute encephalitis syndrome: inflammation of the brain, most often caused by viruses. The inflammation, which is essentially what encephalitis is, can be part of another disease or medical problem such as meningitis (inflammation of the covering of the brain (the meninges). Seven out of ten people with encephalitis will die within a few days. This is a very severe disease.
- Chronic encephalitis syndrome: is essentially the same as the acute form (see above) but with a longer time course with less severe symptoms. The patients are generally less debilitated over time.