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Brain abscess

A brain abscess is a pus-filled swelling in the brain. It usually occurs when bacteria or fungi enter the brain tissue after an infection or severe head injury.

Although the risk of developing a brain abscess is extremely low in England, it is a life-threatening condition and should be diagnosed and treated as soon as possible.

Symptoms of a brain abscess

The symptoms of a brain abscess may develop quickly or slowly but can include:

When to get medical advice

Any symptoms that suggest a problem with the brain and nervous system should be treated as a medical emergency. These include:

If you or someone you know experiences any of these symptoms, phone 999 immediately and ask for an ambulance.

Any symptoms that suggest a worsening infection, such as a high temperature or being sick, should be reported to your GP immediately.

If your GP is not available, contact your local out-of-hours service or call NHS 111.

Causes of a brain abscess

There are 3 main ways a brain abscess can develop. These are:

However, in some cases, the source of the infection remains unknown.

Read more about the causes of a brain abscess.

Diagnosing a brain abscess

If a brain abscess is suspected, an initial assessment will be made based on your symptoms, medical history and whether you've had a recent infection or a weakened immune system.

Blood tests can also be carried out to check for an infection.

If you're referred to hospital for further tests, you may have either:

If an abscess is found, a procedure known as CT-guided aspiration may be used to remove a sample of pus for testing. This involves using a CT scan to guide a needle to the site of the abscess.

Treating a brain abscess

A brain abscess is regarded as a medical emergency. Swelling caused by the abscess can disrupt the blood and oxygen supply to the brain. There's also a risk of the abscess bursting (rupturing).

If left untreated, a brain abscess can cause permanent brain damage and could be fatal.

A brain abscess is usually treated using a combination of:

Treatment with antibiotics often begins before a diagnosis is confirmed, to reduce the risk of complications.

Read more about treating a brain abscess.

Complications of a brain abscess

Complications of a brain abscess can include: