Brain abscesses are rare but serious infections, occurring in about 4 per million people annually, with roughly 1,500-2,500 cases yearly in the U.S., and are considered a neurosurgical emergency due to potential fatality. They are more common in men and young adults, especially those with weakened immune systems, and can arise from dental issues, sinus/ear infections, or trauma, though sometimes the source is unknown.
If the immune system is unable to kill an infection, it will try to limit its spread by using healthy tissue to form an abscess, to stop the pus infecting other tissue. Infections of the brain are rare because the body has evolved a number of defences to protect this vital organ.
Between 10% and 30% of all brain abscess cases are deadly.
Diagnosing brain abscess
For this reason, the diagnosis of brain abscess is often not made until about two weeks after symptoms first develop. In some cases, people with brain abscesses develop seizures or neurological changes, such as muscle weakness on one side of the body, before the diagnosis is made.
An abscess may form in your brain when bacteria from an infection elsewhere in your head or bloodstream or from a wound enter your brain.
A brain abscess is a localized collection of pus within the brain parenchyma, often resulting from infection. Common causes include hematogenous spread from distant infections (eg, lung infections and endocarditis), local infections (eg, otitis media and sinusitis), and posttraumatic or postoperative infections.
Causes. Abscesses occur when an area of tissue becomes infected and the body's immune system tries to fight and contain it. White blood cells (WBCs) move through the walls of the blood vessels into the area of the infection and collect in the damaged tissue. During this process, pus forms.
Brain abscesses are focal parenchymal infections, most often occurring in the first two decades of life. Overall, 25% of brain abscesses are seen in children and most often between 4–10 years of age. Abscesses begin as regions of cerebritis and progress to suppurative collections of encapsulated pus within 14 days.
Brain abscess development can be divided into four stages: 1) early cerebritis (1–4 days); 2) late cerebritis (4–10 days); 3) early capsule formation (11–14 days); and 4) late capsule formation (>14 days). Staging of brain abscess in humans has been based on findings obtained during CT or MRI scans.
Symptoms of a brain abscess
changes in mental state – such as confusion or irritability. problems with nerve function – such as muscle weakness, slurred speech or paralysis on one side of the body. a high temperature. seizures (fits)
Once the abscess has been treated, the bone is replaced. The operation usually takes around 3 hours, which includes recovery from general anaesthetic, where you're put to sleep.
A severe and ongoing headache is often the first sign of brain swelling. This headache feels more intense than usual and may feel like pressure in your head. Not all headaches mean brain swelling, but a severe one needs medical attention.
This condition usually occurs when a virus infects the brain. The infection may affect one area or be widespread. Viruses are the most common causes of infectious encephalitis, including some that can be passed by mosquitoes or ticks. Very rarely, encephalitis may be caused by bacteria, fungus or parasites.
Abscesses can form very quickly. Sometimes they form only one or two days after the infection starts. There are two types of abscesses: A gum abscess (also called a periodontal abscess) usually is caused by an infection in the space between the tooth and gum.
The most common sites for brain abscess were the frontal lobe (33%), followed by the temporal lobe (20%) and temporo‐parietal lobe (10%).
The infection and inflammation can range from mild to severe. Encephalitis is rare and affects approximately 4,000 people in the UK each year. Only certain viruses have the capability to affect the nerves and gain access to the central nervous system (the brain and spinal cord).
A brain abscess can press on the brain, damage tissue, or block blood vessels in the brain. It's a serious and life-threatening condition that must be treated right away. With treatment, some children can recover with few or no complications.
Symptoms of an abscess may include swelling, redness, pain and fever. Abscesses usually need medical treatment to prevent further infection.
The diagnosis is usually made by a combination of the history, physical exam and brain imaging. MRI with and without contrast is the study of choice. Unlike other brain infections, a brain abscess is usually not diagnosed by CSF studies.
A cerebral abscess often occurs when bacteria or fungi make their way into your brain. This can happen either through your bloodstream or from an infected area in your head, such as your ears or sinuses. An injury to your head or head surgery can also let in germs that can cause an abscess.
When bacteria is introduced underneath the skin, the body combats the infection by walling it off, thereby creating an abscess. After about a week, the center of the abscess becomes soft and mushy (filled with pus). The overlying skin then thins out and becomes ready for draining.
An abscess forms when your immune system walls off an infection, usually bacterial (like Staph), creating a pocket filled with pus (bacteria, white blood cells, dead tissue) that can't drain, often entering through cuts, follicles, or blocked glands. While bacteria are the main culprit, fungi, parasites, or blocked ducts can also cause them, leading to painful, swollen, red lumps, and sometimes deeper internal abscesses from surgery or existing conditions.
When we're stressed out, our bodies find it harder to fight infection as our immune systems are weaker. If bacteria in the mouth gets inside the teeth, gums or bone, this can lead to dental abscesses, which can be incredibly painful and will require a dentist to clear the build-up of pus that accumulates.
A deficiency in local or systemicimmunologic defense, particularly of neutrophils, also can lead to abscesses. Conditions that cause such a deficiency include congenital or acquired neutropenia,leukocyte adhesion deficiency, and chronic granulomatous disease.
Abscesses can form in almost any part of the body. The skin, under the skin, and around the teeth are the most common sites. Abscesses may be caused by bacteria, parasites, and foreign substances. Abscesses in the skin are easy to see.