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What Is Encephalitis?

Encephalitis is an inflammation of the brain. This is an uncommon but serious condition which requires urgent treatment in hospital.  It can cause personality changes, seizures, weakness, and other symptoms depending on what part of the brain is inflamed. Anyone can be affected, but the very young and very old are most at risk and those with a weak immune system.

The disease is caused usually caused by one of several viral infections, and sometimes can be called viral encephalitis. With proper care many people recover from encephalitis and the most suitable treatment and the chance of recovery depends on the virus involved and the severity of the inflammation.

Most cases of encephalitis, the inflammation will resolve in a few days. For severe cases, it may require weeks or months for them to get better and it can sometimes cause permanent brain damage, loss of brain function or even death.

Types of Encephalitis

Primary encephalitis: This can result if a fungus, virus or bacterium infects the brain. Primary infection may be a reactivation of a virus that had been inactive after a previous illness.

Secondary encephalitis(or post-infectious) : This condition results from a faulty immune system reaction to an infection elsewhere in the body. Instead of attacking only the cells causing the infection, the immune system also mistakenly attacks healthy cells in the brain and often occurs two or three weeks after infection.

Other forms of encephalitis are:

Human immunodeficiency virus (HIV) and the brain: HIV-meningoencephalitis is an infection of the brain and the lining of the brain (called the meninges) by HIV. It can happen a few weeks or months after a person first contracts HIV infection.

Subacute sclerosing pan-encephalitis (SSPE): SSPE is a very rare type of encephalitis which can follow natural (wild) measles virus infection.

Encephalitis Lethargica: An uncommon form of encephalitis, also known as sleeping sickness. There was an epidemic in the 1920s, however, there has been no epidemic since, although isolated cases have been reported.


Symptoms may be mild, to begin with, but can become more serious over hours or days.

Early symptoms

The first symptoms of encephalitis can be similar to flu, such as:

  • a high temperature (fever) of 38C (100.4F) or above
  • a headache
  • feeling and being sick
  • aching muscles and joints
  • spotty or blistery rash on skin

In many cases, these symptoms do not always appear and sometimes the first sign of encephalitis may be one or more of the more serious symptoms.

More severe symptoms develop when the brain is affected, such as:

  • confusion or disorientation
  • drowsiness
  • seizures (fits)
  • changes in personality and behaviour, such as feeling very agitated
  • difficulty speaking
  • weakness or loss of movement in some parts of the body
  • seeing and hearing things that aren’t there (hallucinations)
  • loss of sensation in certain parts of the body
  • involuntary eye movements, such as side-to-side eye movement
  • vision problems
  • loss of consciousness

There may also be symptoms of meningitis, which can often be the first conclusion. These include severe headache, sensitivity to bright lights, a stiff neck and a spotty rash that doesn’t disappear when a glass is pressed against it.


Encephalitis can occur if an infection spreads to the brain.

Many of the infections associated with the condition are quite common and are usually mild. It is most often due to a virus such as:

  • herpes simplex viruses, which cause cold sores and genital herpes (this is the most common cause of encephalitis)
  • the varicella-zoster virus, which causes chickenpox and shingles
  • measles, mumps and rubella viruses
  • viruses spread by animals, such as tick-borne encephalitis, Japanese encephalitis, rabies (and possibly Zika virus)

You can catch these infections from someone else, but encephalitis itself cannot be spread from person to person.

Diagnosing Encephalitis

The symptoms of encephalitis can have a number of possible causes and can often be symptoms of meningitis, so several tests may be needed to diagnose it.

  1. Brain Scans

The brain scan can show whether you have encephalitis. It can also show other problems such as a stroke, brain tumour or brain aneurysm.

The two types of scan are:

  • a CT scan – several X-rays are taken from different angles and are put together by a computer to create a detailed image of the brain
  • an MRI scan – strong magnetic fields and radio waves are used to produce a detailed image of the brain
  1. Lumbar puncture

A lumbar puncture is a procedure to remove some fluid from around the spinal cord (the nerves running up the spine) so it can be checked for signs of encephalitis. This is whereby a needle is inserted into the lower part of the spine and a sample of the fluid is removed.

Other tests

Several other tests may also be needed to help diagnose encephalitis and check for an underlying cause. These may include an electroencephalogram (EEG) whereby small electrodes are placed on your scalp, which pick up the electrical signals from your brain and show abnormal brain activity and even tests of your blood, urine or other bodily fluids to check for an infection.


Once you have been diagnosed with encephalitis, you will need to be treated urgently. The treatment will cover tackling the underlying cause, relieving symptoms and supporting bodily functions.

Encephalitis is treated in a hospital, usually in an intensive care unit if you are very ill and need extra care. This can vary from a few days to several weeks or even months, depending on how well the treatment works and if any complications of encephalitis occur.

Possible treatments include:

  • antiviral medication – used if encephalitis is caused by the herpes simplex or chickenpox viruses; it’s usually given into a vein three times a day for two to three weeks
  • steroid injections – used if encephalitis is caused by a problem with the immune system and sometimes in cases linked to the chickenpox virus; treatment is usually for a few days
  • immunoglobulin therapy – medication that helps control the immune system, which may be needed if steroids don’t help
  • plasmapheresis – a procedure which removes the substances that are attacking the brain from the blood, which may be needed if immunoglobulin therapy doesn’t help
  • surgery to remove abnormal growths (tumours) – done if encephalitis was triggered by a tumour somewhere in the body
  • antibiotics or antifungal medication – used if encephalitis is caused by a bacterial or antifungal infection

If there’s no treatment for the underlying cause, treatment is given to support the body, relieve symptoms, and allow the best chance of recovery (see below).

Other treatments

Encephalitis puts a lot of strain on the body and can cause a range of unpleasant symptoms. Most people treated will want to relieve these symptoms and to support certain bodily functions until they are feeling better. This may involve fluids given into a vein to prevent dehydration, painkillers to reduce discomfort, medication to control seizures or help a person relax, and many other forms depending on the patient and the seriousness of encephalitis.

Occasionally, surgery is required to remove a small piece of the skull if the pressure inside the brain increases and medication isn’t helping.

Encephalitis and clinical negligence

Encephalitis is not easy to diagnose or easy to treat. Despite the best efforts of doctors, the outcome is not always what the patient would hope for. On rare occasions, the standard of treatment received by a patient may fall short of that which the medical profession itself would expect. This could be a failure to carry out the appropriate tests, failure to diagnose the condition as the symptoms are very similar to meningitis or failure to provide the appropriate treatment.

In the cases where it can be shown that the standard was unacceptable, it is possible you may have a potential clinical negligence claim. If you feel that is the case contact the clinical negligence team at Wilson Browne Solicitors.