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Quick Facts

Brain Abscess


The Manual's Editorial Staff

Last full review/revision Sep 2020| Content last modified Sep 2020
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What is a brain abscess?

An abscess is a pocket of pus. A brain abscess is a pocket of pus in your brain.

  • One or more brain abscesses can form when an infection spreads from somewhere else in your body

  • An abscess puts pressure on your brain

  • A brain abscess is dangerous and can be fatal

  • Symptoms include headache, sleepiness, feeling sick to your stomach, and sometimes weakness on one side of your body or seizures

  • Doctors do a CT scan or MRI of your head to find an abscess

  • Treatment includes antibiotics and sometimes surgery to drain the abscess

What causes a brain abscess?

An abscess is caused by an infection from bacteria, fungi, or parasites. The infection usually starts somewhere else and goes to your brain.

  • Infections can spread from another place in your head, such as your tooth, sinuses, or ear

  • Infections can travel through your blood from another part of your body

Sometimes infections enter your brain when you have a bad head injury or brain surgery.

People who have a problem with their immune system such HIV infection have an increased risk of brain abscess caused by toxoplasmosis or a fungus.

What are the symptoms of a brain abscess?

A brain abscess can cause different symptoms, depending on where it is and how much it swells. Symptoms can include:

  • Fever and chills, which may start early and then go away

  • Headache

  • Feeling sick to your stomach or throwing up

  • Feeling very sleepy

  • Feeling weak on one side of your body

  • Problems thinking

  • Seizures or coma

How can doctors tell if I have a brain abscess?

Doctors find an abscess with an imaging test, such as an MRI or CT scan. They figure out which type of infection caused the abscess by taking a sample of the pus and trying to grow germs from it in a lab.

How do doctors treat a brain abscess?

Doctors treat a brain abscess using:

  • Antibiotics for 4 to 6 weeks to get rid of the infection

  • Corticosteroids to lower swelling in your brain

  • Medicines to prevent seizures

  • Sometimes draining the abscess with a needle

  • Sometimes doing surgery to remove the whole abscess

If you have a condition that makes your immune system weak, you may need antibiotics for the rest of your life.

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