Encephalitis is an uncommon but serious condition in which the brain becomes swollen. It can be life threatening and require urgent treatment in hospital. Anyone can be affected, but the very young and very old are most at risk.

Encephalitis sometimes starts off with flu-like symptoms such as a fever and headache. More serious symptoms come on over the following hours, days or weeks, including confusion or disorientation, seizures, changes in personality and behaviours, weakness or loss of movement in some of the body parts, and loss of consciousness.

It is not always clear what causes encephalitis, but it can be caused by a viral infection. There are several common viruses that can spread to the brain and cause encephalitis in rare cases such as the herpes simplex virus which causes cold sores and genital herpes.

A problem with the immune system can cause the body to attack itself causing inflammation in the brain. Or a bacterial or fungal infection although these cases are much rarer. Encephalitis is not infectious and cannot be caught from other people.

Treatment for encephalitis is more effective the earlier it is started and must be provided in a hospital. The exact treatment will depend on the underlying cause, but may include antiviral medications, steroid injection, anti-biotic or antifungal medication, pain killers to control fever, seizure medication or treatment to help control the immune system. A patient with encephalitis may need to remain in hospital for a long period of time depending on the severity.

Some patients will make a full recovery from encephalitis, although it can be a long process. Others may never make a full recovery and can be left with long-term damage to their brain. It may cause complications such as memory loss, frequent seizures or fits, personality and behavioural changes, problems with attention or persistent tiredness.