What is encephalitis?
Encephalitis is a condition in which there is inflammation (swelling) of the brain. It is a serious condition, often caused by infections or the immune system mistakenly attacking the brain.
Encephalitis needs urgent hospital treatment as it can be life-threatening.
What causes encephalitis?
In many cases, the exact cause of encephalitis remains unknown. However, possible causes include:
Infections causing inflammation in the brain, known as infectious encephalitis. This is most commonly caused by viral infections such as the herpes simplex virus or the varicella zoster virus. In rarer cases, it can be from bacterial and fungal infections.
The body’s immune system mistakenly targeting the brain following an infection or tumour elsewhere in the body. This is known as autoimmune encephalitis.
Infections transmitted through mosquito or tick bites.
What happens in encephalitis?
The brain can swell when an infection or abnormal immune response causes inflammation. The swelling itself can damage brain tissue and may also cause a build-up of pressure. This can also cause damage, as the brain only has a limited amount of space within the skull.
A person with encephalitis may initially present with flu-like symptoms such as headaches, a high temperature and body aches. These can be followed by more serious symptoms over the hours, days or weeks that follow, such as:
confusion;
changes in behaviour or personality;
drowsiness;
hallucinations;
seizures;
difficulty speaking;
weakness or loss of movement;
vision problems;
neck stiffness;
loss of consciousness.
Call 999 if flu-like symptoms are followed by confusion, significant changes in behaviour or personality, difficulty speaking, weakness or loss of movement, increasing drowsiness, a seizure or loss of consciousness.
You should also call 999 if someone has a seizure for the first time, confusion, changes in behaviour or personality, difficulty speaking, weakness or loss of movement, increasing drowsiness or loss of consciousness. If you are experiencing these symptoms, do not drive yourself to A&E.
Catherine's story
"On Boxing Day 2016, when Alan collapsed with absolutely no warning, our lives changed forever.
"A terrible time when he was in a coma in intensive care was followed by a year in hospital. The diagnosis was Autoimmune Encephalitis and the resulting brain injury meant that when Alan finally came home to us, he was a completely different person."
Find out more about Catherine and Alan's story.
What happens after encephalitis is treated?
Following treatment for encephalitis, a person will usually need to stay in hospital. They will continue to be monitored by the medical team. The length of the hospital stay will depend on the severity of the illness, the treatment needed and the person’s individual circumstances.
The person may have rehabilitation to help manage the physical, cognitive or emotional impact of encephalitis. Rehabilitation may take place in hospital, at a specialist rehabilitation unit or through community-based services.
The person may be able to return directly home from hospital, but they will need to continue resting. The time needed to recover and return to usual activities varies from person to person.
Clair's story
When Clair woke up in hospital after having encephalitis, she had no idea that the strangers around her bed were her closest family members. She was struggling with her memory and was unable to remember the past year of her life.
Three years on, Clair, 28, still experiences short-term memory loss, and struggles to remember the time that has passed since her injury.
Read more about how Clair learnt to manage life with encephalitis.
