Brain Abscess

What Is It?

A brain abscess is a collection of pus enclosed in the brain tissue. Caused by a bacterial or fungal infection, a brain abscess can develop as a complication of an infection, trauma or surgery. They are generally rare, although people with weakened immune systems (such as people with HIV or those who have received an organ transplant) are more likely to get a brain abscess.

This type of infection typically begins in one of these ways:

• It spreads from a nearby site, such as a middle-ear infection, sinus infection or dental abscess.
• Blood carries the infection from elsewhere in the body to the brain.
• Infectious organisms enter the brain through a penetrating injury, such as a gunshot wound, or from neurosurgical procedures or facial trauma.

Symptoms

Symptoms vary depending on the size and location of the abscess. More than 75 percent of people with a brain abscess have a dull, achy headache. For many people this is the only symptom. The pain usually is limited to the side of the brain where the abscess is, and the pain typically becomes worse until the abscess is treated. Aspirin and other pain medications do not relieve the pain.

About half of the people with a brain abscess have a low-grade fever. Other symptoms may include nausea and vomiting, neck stiffness, seizures, personality changes and muscular weakness on one side of the body.

Diagnosis

Diagnosing a brain abscess is not easy because the early symptoms are so general. For example, many things can cause headaches. In some cases, people with brain abscesses are in considerable distress, complaining of a constant headache that has gotten progressively worse, seizures or neurological changes, such as muscular weakness on one side of the body.

Your doctor will ask about your medical and travel history to determine your risk of having certain infections. The doctor also will ask if you have any of the symptoms of brain abscess. If you do, he or she will ask when they started, how they've progressed and whether you've had a recent infection.

You may need diagnostic tests, such as computed tomography (CT) or magnetic resonance imaging (MRI) scans. These provide pictures of the inside of the brain. The abscess will appear as one or more spots. Blood and other body fluids may be studied to find the original source of the infection. If the diagnosis remains uncertain, a neurosurgeon can remove a piece of the brain abscess with a fine needle.

Expected Duration

A brain abscess can grow very quickly, typically becoming fully formed within about two weeks. Your doctor will begin treatment immediately after you are diagnosed. Prompt medical attention is the key to relieving your symptoms more quickly and minimizing damage to your long-term health.