Encephalitis is defined as inflammation of the brain tissue. It is a term that is mainly used for an acute illness of the brain caused either by a viral infection or by autoimmune conditions affecting the brain. The incidence of encephalitis varies across the world. In the UK it is estimated that there are between 2-4,000 cases each year of which one third are children. Encephalitis has been known for centuries but research in the 21st Century has identified types of encephalitis that were previously unrecognised as part of the encephalitic spectrum. Although the actual incidence of encephalitis remains unchanged the number of children diagnosed with encephalitis has increased.
Regardless of the cause of encephalitis, the resulting symptoms are the same depending on the region of the brain that is affected.
Acute encephalitis is often a life-threatening disorder. Death due to encephalitis is often the result of low levels of oxygen. Brain tissue, unlike other body tissues, cannot survive even short periods without oxygen. As the inflammation increases, the brain swells restricting the blood vessels that supply oxygen to brain tissues. Death can be very quick leaving parents utterly stunned.
When a child / young person does recover from acute encephalitis, the encephalitis itself will have resolved, it will no longer be present. The resulting brain damage however is permanent and irreversible.