Prevention of encephalitis:
The most effective way to protect against encephalitis is to get the measles, mumps, and rubella (MMR) vaccine when at a young age.
The first MMR vaccination should be given to all children at around 13 months of age, with a booster dose given before they start school (when they are between 3-5 years of age). Between 5-10% of children are not fully immune after the first dose, so the booster jab helps to increase protection and results in less than 1% remaining at risk.
Vaccinations are also available for two types of encephalitis that are spread by insects:
- Japanese encephalitis - spread by mosquitoes
- tick-borne encephalitis - transmitted by bite of an infected tick or, less commonly, drinking unpasteurised milk from infected animals, particularly goats
Treatment for encephalitis:
3 important aims of the treatment:
- to use anti-viral medication to halt and then reverse, the process of infection
- to control any immediate complication of encephalitis (e.g. seizures or dehydration, caused by fever)
- try to prevent long-term complications (e.g. memory loss or epilepsy)
Most people are transfered directly to an intensive care unit (ICU) in hospital.
Aciclovir - primary option treatment used in England. Aciclovir has proved to be very effective in treating cases of encephalitis that have been caused by the herpes virus.
The earlier aciclovir is used in cases of encephalitis, the lower the risk of long-term complications. Due to this, treatment with aciclovir is usually started before all the diagnostic tests are complete. If tests reveal that the encephalitis has a different cause, such as bacteria, then aciclovir will be substituted with an appropriate medication.
Aciclovir is given by intravenous infusion usually 3 times a day for at least 10 days and possible for 14-21 days.
Common side effects of aciclovir include:
Less common side effects include:
- liver damage
- drop in the amount of white blood cells produced by the bone marrow, which can make you more vulnerable to infection
Corticosteroids are used in cases of post-infectious encephalitis because they will temporarily stop the immune system from working (immunosuppressants). This will reduce any inflammation in the brain and prevent further damage.
If a person is experiencing repeated seizures due to encephalitis, sedatives, such as benzodiazepine, can be used to prevent further seizures.
Brain swelling Care in an intensive care unit may be needed to measure
and treat raised pressure in the head and to treat breathing difficulties by
artificial ventilation. Powerful diuretics (e.g. Mannitol) may be needed to
reduce the pressure inside the head.
There is a long list of viruses that can cause encephalitis, most of which are impossible to avoid, but which are the important ones?
Aciclovir, the only established treatment, is only effective for encephalitis caused by herpes simplex virus (HSV). Although this is the most commonly diagnosed cause of viral encephalitis in the West, HSV only accounts for about 10-30% of all patients with suspected viral encephalitis.
In many other cases, we don't know the identity of the virus or other organism that produces the inflammation of the brain. Much more research needs to go into understanding the causes, epidemiology, treatment and prevention of viral encephalitis.