Encephalitis is inflammation of the brain. Viral infections are the most common cause of the condition. Encephalitis can cause flu-like symptoms, such as a fever or severe headache. It can also cause confused thinking, seizures, or problems with senses or movement. However, many cases of encephalitis result in only mild flu-like symptoms or even no symptoms.
The most common types of encephalitis are:
1. infectious – inflammation occurs as a direct result of an infection, which is often viral
2. post-infectious – inflammation is caused by the immune system reacting to a previous infection, and can occur days, weeks or months after the initial infection
3. autoimmune – inflammation is caused by the immune system reacting to a non-infectious cause, such as a tumour
4. chronic – inflammation develops slowly over many months and can be due to a condition such as HIV; in some cases, there's no obvious cause.
Most people with viral encephalitis have either no symptoms or mild flu-like symptoms, such as Headache, fever, aches in muscles or joints, fatigue or weakness. Additional signs and symptoms of more serious encephalitis may include confusion, agitation or hallucinations, seizures, loss of sensation or paralysis in certain areas of the face or body, muscle weakness, double vision, perception of foul smells, such as burned meat or rotten eggs.
Treatment depends on the type of encephalitis but may include anti-viral medication, steroid injections, immunosuppressants medicines that stop the immune system attacking healthy tissue.