Brain Abscess

An abscess is a self-contained pocket of pus that can form anywhere in the body, including on the skin, under a tooth, or in a hair follicle. An abscess that develops in the brain is especially dangerous because it puts pressure on surrounding brain matter as it grows and can cause neurological damage. It causes intense inflammation of the surrounding brain, often resulting in severe swelling. Immediate treatment is required.

A brain abscess, also called a cerebral abscess, usually develops as a result of an infection or injury. White blood cells rush to the site of a trauma or infection, and as those cells accumulate along with bacteria and dead tissue the body responds by walling it all off into a capsule of pus. The original injury or infection can be a sinus infection, a dental abscess, or a puncture wound that becomes infected. That injury or infection can set off a chain of events that causes a brain abscess to form, grow, or even rupture.

A brain abscess is typically diagnosed using a CT or MRI scan. Depending on the size and location of the abscess, a neurosurgeon may aspirate it (suck it out) through a small “keyhole” opening in the skull; larger abscesses often require full craniotomies to open the skull and allow a neurosurgeon to drain it. A strong course of antibiotics helps to ensure that all the infectious material is eliminated. Very small abscesses may be treated with antibiotics only, with careful monitoring to be sure the infection is responding well.

Symptoms of a brain abscess include severe headache, nausea, lethargy, or even seizures. Emergency attention is required any time an individual experiences what he or she describes as “the worst headache of my life,” as it may signal a stroke, a ruptured aneurysm, or other urgent neurological condition, including an abscess. Left untreated, a brain abscess may lead to neurological damage, and ultimately death.

The overall mortality rate from a brain abscess is 10 percent, but if the abscess ruptures into the ventricle (the fluid chambers in the brain), the mortality rate goes up to as much as 25 to 40 percent.  Survival statistics don’t tell the whole story, as 45 percent of cerebral abscess patients develop some neurologic disability afterwards, 29 percent develop hemiparesis (weakness on one side of the body), and 27 percent develop seizures. 

The urgent nature of many brain conditions makes it critical to seek care at a major medical center, where experts have the skills and tools available to treat emergencies like these. At the Weill Cornell Medicine Brain and Spine Center, our world-class faculty members are available at the main campus of NewYork-Presbyterian Weill Cornell Medical Center, as well as at the NewYork-Presbyterian locations in Queens, Brooklyn, and Lower Manhattan.

Reviewed by Michael Ayad, M.D., PhD.
Last reviewed/last updated: August 2023

See Related Patient Stories:
A "20 Out of 10" Headache

No Patient Exists in a Vacuum
Amazing Kid Returns to New York for a Team Reunion