Brain abscess
Abscess - brain; Cerebral abscess; CNS abscessA brain abscess is a collection of pus, immune cells, and other material in the brain, caused by a bacterial or fungal infection.
Causes
Brain abscesses commonly occur when bacteria or fungi infect part of the brain. As a result, swelling and irritation (inflammation) develop. Infected brain cells, white blood cells, live and dead bacteria or fungi collect in an area of the brain. Tissue forms around this area and creates a mass or abscess.
The germs that cause a brain abscess can reach the brain through the blood. Or, they enter the brain directly, such as during brain surgery. In some cases, a brain abscess develops from an infection in the sinuses.
The source of the infection is often not found. However, the most common identified source is a lung infection. Less often, a heart infection is the cause.
The following raise your chance of developing a brain abscess:
- A weakened immune system (such as in people with HIV/AIDS)
HIV/AIDS
Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). When a person becomes infected with HIV, the ...
Read Article Now Book Mark Article - Chronic disease, such as cancer
- Drugs that suppress the immune system (corticosteroids or chemotherapy)
Chemotherapy
The term chemotherapy is used to describe cancer-killing drugs. Chemotherapy may be used to:Cure the cancerShrink the cancerPrevent the cancer from ...
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Congenital heart disease
Congenital heart disease
Congenital heart disease (CHD) is a problem with the heart's structure and function that is present at birth.
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Symptoms
Symptoms may develop slowly, over a period of several weeks, or they may develop suddenly. They may include:
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Changes in mental status, such as confusion, slow response or thinking, unable to focus, or sleepiness
Changes in mental status
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
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Decreased ability to feel touch or pain (sensation)
Decreased ability to feel touch or pain...
Numbness and tingling are abnormal sensations that can occur anywhere in your body, but they are often felt in your fingers, hands, feet, arms, or le...
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- Headache, seizures, or stiff neck
Seizures
A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...
Read Article Now Book Mark Article - Language problems
- Loss of muscle function, typically on one side
- Vision changes
- Vomiting
- Weakness in a limb (such as an arm or leg)
Exams and Tests
A brain and nervous system (neurological) exam will usually show signs of increased pressure inside the skull and problems with brain function.
Increased pressure inside the skull
Increased intracranial pressure is a rise in the pressure inside the skull that can result from or cause brain injury.
Read Article Now Book Mark ArticleTests to diagnose a brain abscess may include:
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Blood cultures
Blood cultures
A blood culture is a laboratory test to check for bacteria or other germs in a blood sample.
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Chest x-ray
Chest x-ray
A chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.
Read Article Now Book Mark Article - Complete blood count (CBC)
CBC
A complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...
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Head CT scan
Head CT scan
A head computed tomography (CT) scan uses many x-rays to create pictures of the head, including the skull, brain, eye sockets, and sinuses.
Read Article Now Book Mark Article - Electroencephalogram (EEG)
EEG
An electroencephalogram (EEG) is a test to measure the electrical activity of the brain.
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MRI of head
MRI of head
A head MRI (magnetic resonance imaging) is an imaging test that uses powerful magnets and radio waves to create pictures of the brain and surrounding...
Read Article Now Book Mark Article - Testing for the presence of antibodies to certain germs
Antibodies
Antibody titer is a laboratory test that measures the level of antibodies in a blood sample.
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A needle biopsy is usually performed to identify the cause of the infection.
Biopsy
A biopsy is the removal of a small piece of tissue for laboratory examination.
Read Article Now Book Mark ArticleTreatment
A brain abscess is a medical emergency. Pressure inside the skull may become high enough to be life threatening. You will need to stay in the hospital until the condition is stable. Some people may need life support.
Medicine such as an antibiotic, not surgery, is recommended if you have:
- A small abscess (less than 2 cm)
- An abscess deep in the brain
- An abscess and meningitis
Meningitis
Meningitis is an infection of the membranes covering the brain and spinal cord. This covering is called the meninges.
Read Article Now Book Mark Article - Several abscesses (rare)
- Shunts in the brain for hydrocephalus (in some cases, the shunt may need to be removed temporarily or replaced)
Hydrocephalus
Hydrocephalus is a buildup of fluid inside the skull that leads to the brain pushing against the skull. Hydrocephalus means "water on the brain. "...
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Toxoplasmosis
Toxoplasmosis is an infection due to the parasite Toxoplasma gondii.
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You may be prescribed several different types of antibiotics to make sure treatment works.
Antifungal medicines may also be prescribed if the infection is likely caused by a fungus.
Surgery is needed if:
- Increased pressure in the brain continues or gets worse
- The brain abscess does not get smaller after medicine
- The brain abscess contains gas (produced by some types of bacteria)
- The brain abscess might break open (rupture)
- The brain abscess is large (more than 2 cm)
Surgery consists of opening the skull, exposing the brain, and draining the abscess. Laboratory tests are often done to examine the fluid. This helps identify the cause of the infection, so that the right antibiotics or antifungal medicine can be prescribed.
Needle aspiration guided by CT or MRI scan may be needed for a deep abscess. During this procedure, medicines may be injected directly into the mass.
Aspiration
Aspiration means to draw in or out using a sucking motion. It has two meanings:Breathing in a foreign object (for example, sucking food into the air...
Read Article Now Book Mark ArticleCertain diuretics (medicines that reduce fluid in the body, also called water pills) and steroids may also be used to reduce the swelling of the brain.
Outlook (Prognosis)
If untreated, a brain abscess is almost always deadly. With treatment, the death rate is about 10% to 30%. The earlier treatment is received, the better.
Some people may have long-term nervous system problems after a brain abscess or surgery.
Possible Complications
Complications may include:
- Brain damage
- Meningitis that is severe and life threatening
- Return (recurrence) of infection
- Seizures
When to Contact a Medical Professional
Go to a hospital emergency room or call 911 or the local emergency number if you have symptoms of a brain abscess.
Prevention
You can reduce the risk of developing a brain abscess by getting treated for infections or health problems that can cause them.
Some people, including those with certain heart disorders, may receive antibiotics before dental or other procedures to help reduce the risk of infection.
References
Gea-Banacloche JC, Tunkel AR. Brain abscess. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 90.
Nath A, Berger JR. Brain abscess and parameningeal infections. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 385.
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Amebic brain abscess - illustration
Amebiasis, normally an infection of the intestinal tract, may spread and infect other organs such as the liver or brain. Infection of the brain can be fatal. In this slide, ameba are shown in a sample of brain tissue. Ameba represent a serious infection in immunocompromised individuals. (Image courtesy of the Centers for Disease Control and Prevention.)
Amebic brain abscess
illustration
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Brain - illustration
The brain is that part of the central nervous system contained in the skull and is composed of cerebrum, cerebellum, pons, and medulla oblongata.
Brain
illustration
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Amebic brain abscess - illustration
Amebiasis, normally an infection of the intestinal tract, may spread and infect other organs such as the liver or brain. Infection of the brain can be fatal. In this slide, ameba are shown in a sample of brain tissue. Ameba represent a serious infection in immunocompromised individuals. (Image courtesy of the Centers for Disease Control and Prevention.)
Amebic brain abscess
illustration
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Brain - illustration
The brain is that part of the central nervous system contained in the skull and is composed of cerebrum, cerebellum, pons, and medulla oblongata.
Brain
illustration
Review Date: 12/4/2022
Reviewed By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.