Encephalitis

9-minute read

If your baby is under 3 months old and has a fever over 38°C, seek urgent medical attention or go to the nearest hospital emergency department.

If you or your child has symptoms of encephalitis, a seizure or altered alertness, go to the nearest emergency department immediately, or call triple zero (000) for an ambulance.

Key facts

Encephalitis is inflammation of the brain and can be life-threatening.
It's mainly caused by viruses but can also be caused by bacteria, parasites or your immune system.
Symptoms may include drowsiness, confusion, seizures, fever and headaches.
Encephalitis should be monitored and treated in hospital.
After recovering from encephalitis you may have lasting medical issues such as seizures or problems with memory, balance, hearing or speaking.

What is encephalitis?

Encephalitis is an inflammation of the brain. It is usually caused by a virus. It is rare, but can be life-threatening. Encephalitis can lead to permanent brain damage or death.

What are the symptoms of encephalitis?

Encephalitis can start with flu-like symptoms and progress to severe neurological problems.

Flu-like symptoms may include:

high fever and weakness
headaches
nausea and vomiting

Neurological symptoms can appear suddenly, and may include:

confusion
sensitivity to light or vision changes
seizures
difficulty moving or controlling your body
neck stiffness
drowsiness or decreased consciousness

Babies and children with encephalitis may have similar symptoms. Babies may also have a bulging fontanelle (the 'soft spot' of the head starts to swell).

Many of these symptoms can be caused by other conditions. If you experience any of these symptoms, see your doctor so they can diagnose and treat you appropriately.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

When should I call an ambulance or go to the emergency department?

If your baby is under 3 months old and has a fever over 38°C, seek urgent medical attention or go to the nearest hospital emergency department.

If you or your child has symptoms of encephalitis, a seizure, or altered alertness, go to the nearest hospital emergency department immediately or call triple zero (000) for an ambulance.

You should call an ambulance or go to the hospital emergency department if you or someone close to you has severe signs of encephalitis, such as:

severe headache
vomiting
confusion
altered consciousness (a 'blackout')
paralysis
seizures

What should I do while waiting for the ambulance?

Stay on the phone unless you are told to hang up. Follow the call taker's instructions while waiting for the ambulance.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

What causes encephalitis?

Encephalitis can be caused by an infection or by your immune system.

Herpes simplex virus (HSV) is the most common infection that causes encephalitis.

Other infections that can cause encephalitis include but is not limited to:

enteroviruses
toxoplasmosis
viruses transmitted by mosquito bites, such as Murray Valley encephalitis and Japanese encephalitis
chicken pox
measles
mumps
rubella (German measles)

Autoimmune encephalitis happens when your immune system attacks your brain by mistake.

In some cases, the cause of encephalitis cannot be found.

How is encephalitis diagnosed?

Encephalitis is diagnosed with tests to look for the cause and severity, which may include:

MRI or CT scan of your brain
lumbar puncture (LP)
blood tests
a swab taken from your nose or throat
urine tests or stool tests
an EEG (electroencephalogram)

Rarely, a brain biopsy may be needed, if you are not getting better and no cause has been found.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How is encephalitis treated?

Encephalitis treatment depends on the cause and severity.

Treatment with medicines may include:

antiviral or antibiotic medicines
pain relief medicines
medicines to prevent seizures
steroid medicines to reduce inflammation
medicines to lower your immune system's response

You may also be treated with:

intravenous fluids — fluids given directly into a vein
respiratory support — if you have a severe infection, you may need help breathing

While you recover, you may benefit from therapies:

These therapies can help you manage any long-lasting symptoms.

What are the complications of encephalitis?

Encephalitis can lead to serious problems for both adults and children. Your risk of having complications depends on your age and the severity of your condition. Very young children and older adults are at a higher risk of complications. Encephalitis in some cases can cause death.

Complications in adults may include:

epilepsy
difficulty with your memory and concentration
difficulty with balance and control of your bodily functions
headaches and fatigue
changes to your mood and behaviour
difficulty speaking

Complications in babies and children may include:

infections
hearing loss
epilepsy
hydrocephalus (fluid build-up in or around the brain)
developmental delays

Babies may need regular follow-up to check their hearing and development.

Can encephalitis be prevented?

Some infections that cause encephalitis can be prevented through vaccination. For example, the measles, mumps, rubella and varicella vaccines are all part of the routine childhood vaccines recommended in Australia.

Sometimes viruses that cause encephalitis are transmitted via mosquito bites. Mosquito bite prevention (for example, using mosquito repellent, mosquito nets and wearing long sleeves) can help reduce spread of these viruses.

Resources and support

Visit the Brain Foundation for information on encephalitis.
Fight The Bite provides information on how to protect yourself and your family from mosquito bites.
You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available 24 hours a day, 7 days a week.