By Dr Bilal Shirazi | 17 Feb 2021

Understanding encephalitis

Ahead of World Encephalitis Day on 22nd February, get the facts you need to know about this serious condition that many of us know little about.


What is encephalitis?

Encephalitis is an uncommon but potentially devastating condition during which we suffer brain inflammation. Encephalitis can affect anyone, with an estimated 6,000 cases per year in the United Kingdom, and 25,000 per year in the United States.

According to The Encephalitis Society, 78% of people worldwide have no idea what encephalitis even is!

What causes encephalitis?

There are two types of encephalitis:

  • Infectious encephalitis, which is an infection that directly affects the brain.
  • Auto-immune encephalitis, also known as post-infectious encephalitis, which occurs when our immune system mistakenly attacks the brain.

It isn't always obvious what causes encephalitis. However, relatively simple viruses like herpes and chickenpox can cause it in rare instances. Bacterial or fungal infections can also cause encephalitis. Such occurrences are far more infrequent than those caused by viral infections or immune response.

Some types of encephalitis are spread by mosquitoes and ticks, while mammals who carry rabies can also develop encephalitis. One of the biggest challenges clinicians face around understanding encephalitis is how rare it is. Even catching rabies or being bitten by a mosquito rarely leads to the onset of encephalitis.

Encephalitis itself is not, however, transmissible between humans. To develop encephalitis, you would have had to acquire an infection which then causes the condition, or experienced an illness which would cause your immune system to cause brain inflammation.

What are the symptoms of encephalitis?

Encephalitis patients typically experience influenza-like symptoms at first, including fever and headaches.

Another challenging aspect of identifying encephalitis is how slowly or quickly it develops. Patients can experience the onset of more severe symptoms within hours. Others may not experience a change in their condition for a matter of weeks and can continue with their everyday lives while unknowingly experiencing encephalitis.

More severe encephalitis symptoms include:

  • Changes in personality and/or behaviour.
  • Confusion or disorientation.
  • Difficulty speaking.
  • Loss of consciousness.
  • Seizures or fits.
  • Weakness or loss of movement across the body.

You should always seek immediate medical attention if you or someone you know is experiencing these symptoms.

How do clinicians diagnose encephalitis?

It differs from patient to patient. For example, some tests may not be possible if a patient arrives at the hospital in an irritable condition.

Typically, clinicians use a combination of examinations like CT scans, ECG analysis, and blood testing to diagnose encephalitis. As with any medical emergency, earlier diagnosis significantly reduces mortality and improves overall treatment outcomes.

How is encephalitis treated?

As with diagnosis, treatment depends on various factors, including the type of encephalitis and whether any potential side-effects pose a risk to the patient.

Typically, encephalitis patients will receive:

  • Treatment for the specific type of encephalitis they are suffering. This typically consists of antibiotics, antivirals, or immunomodulatory drugs.
  • Treatment for symptoms and complications arising from encephalitis. This will often involve the administering of steroid injections and painkillers.

Medics may also provide oxygen and mechanical ventilation to patients in severe cases.

There is no direct treatment for some types of encephalitis caused by specific viruses. In such cases, clinicians' place all their focus on treating the symptoms and complications.

Some patients will be placed into an induced coma to buy time for brain inflammation to reduce.

Encephalitis prognosis and recovery

Mortality rates for encephalitis are highest among babies under one year old and adults over 55.

Patients who receive no or late treatment for encephalitis have a mortality rate of between 50% - 75%, with survivors almost always experiencing long-term brain damage. Patients who receive treatment have a mortality rate of around 20%. The chances of a full recovery often depend on how quickly encephalitis is identified, and how soon medics provide the necessary treatments.

Due to the nature of neurological injuries, encephalitis recovery will typically involve a variety of medical professionals. These may include:

  • Educational psychologists, where patients have to learn specific neurological skills again.
  • Occupational therapists.
  • Speech therapists.
  • Physiotherapist, to help with motor and coordination functions, which may range from regaining full use of limbs to learning how to walk again.

Even patients who do make a full recovery from encephalitis often take many years to do so. Mental health support both for the patient and those closest to them is often a vital part of the recovery process, which can be long, frustrating, and distressing for all involved.

What are the long-term effects of encephalitis?

Patients who don’t make a full recovery from encephalitis may experience a variety of long-term complications, including:

  • Long-term frequent seizures or fits.
  • Short and long-term memory loss.
  • Difficulty performing motor functions.
  • Fatigue and persistent tiredness.
  • Changes in personality and behaviour.
  • Problems with neurological functions, including paying attention, concentrating, planning, and solving problems.

Can encephalitis be prevented?

As with many conditions, it is not always possible to prevent encephalitis itself. The best protection against encephalitis is vaccination against the viral infections that can lead to it.

In addition to any routine vaccinations you get from the healthcare system in your home country, you should check any vaccinations you require before travelling overseas to specific locations.

World Encephalitis Day 2021

World Encephalitis Day was founded by The Encephalitis Society in 2014 and takes place annually on 22nd February. The event aims to raise awareness of encephalitis and help those affected by the condition, either through suffering it themselves of having a relative or close friend who has done so.

Learn more about World Encephalitis Day, including events that take place around the world and how you can get involved, with The Encephalitis Society.