Brain abscess

definition

A brain abscess is an encapsulated inflammation in the brain. The capsule consists of newly formed tissue (Granulation tissue), which occurs naturally as part of the defense against pathogens and the healing process. In the capsule, the existing cells are destroyed and pus forms. As a result of the inflammation process, fluid is stored in the surrounding tissue, which leads to what is known as brain edema. This cerebral edema can increase intracranial pressure (see: Increased intracranial pressure) - a potentially dangerous process for the patient.

Read more on the subject at: Abscess.

A Brain abscess can have different causes. The possibilities range from one infection with various pathogens, over Injury or surgery-related inflammation, to postponed infections of the respiratory tract or heart.

causes

The causes of a brain abscess are varied, but can be mainly divided into three groups.

Through the Propagation of inflammation of the sinuses (Sinusitis), of Middle ear (Otitis media) or more specific cranial bone structures close to the ear (Mastoiditis) an abscess can form in the front or side lobes of the brain. The pathogens most often come from the group of Strepto- and Staphylococci and are spherical types of bacteria. Also bacteria of the genus Bacteroideswhich are also found in our natural intestinal flora and are important for humans, can be responsible for a brain abscess in the wrong place - in the brain. People with damaged immune system are also susceptible to otherwise rare pathogens. With them, the brain abscess can be caused by a Fungal infection or Toxoplasmosis caused. More rarely, another disorder like a lung infection (pneumonia) or one Heart valve inflammation (Endocarditis) be held responsible for a brain abscess.

In addition to the brain abscesses caused by the pathogen, the traumatic abscesseswhich by Injuries or interventions like Operations a role.

In some patients (10 - 20%) this can also occur after an intensive diagnosis never mind for the brain abscess can be found. That's what the doctor calls one cryptogenic brain abscess.

Symptoms

The symptoms of a brain abscess are very impressive and worsen over time. Since the abscess is usually only on one side of the brain, a so-called half-sided symptomatology arises, a Hemiparesis. Certain muscles or entire extremities (arms and legs) of one half of the body are partially or completely paralyzed and therefore unable to move.

In addition, the examining doctor can observe a congestive papilla by looking into the patient's eyes. This is a bulging of the optic nerve in the fundus, which can be seen through an ophthalmoscope (Fundoscopy) can be seen. It is caused by brain edema.

Another noticeable symptom is clouding of consciousness or total loss of consciousness. At this stage, action should be taken quickly so that consequential damage can be prevented. The examining doctor should also watch out for infections that may be the cause of a brain abscess, such as known inflammation of the respiratory tract and inflammation or injury to the face or head.

In rare cases, so-called meningism occurs, a severe pain when the head is actively bent when the patient is lying flat. Meningism is actually a symptom of meningitis, but can also be an indication of a brain abscess in addition to severe headaches if the abscess is at the edge.

Examination with CT / MRI

A brain abscess can be easily differentiated from other brain diseases using CT (computed tomography) or MRI (magnetic resonance imaging). The representation of the capsule is very impressive and can often be easily identified as a brain abscess.

In the CT image, which is usually done with a contrast medium, a ring-shaped structure is shown that is much lighter than the surrounding brain tissue (hyperdense = high density of the structure). The tissue in the capsule, the pus, is darker than the surrounding tissue due to its liquid form (hypodense = low density of the structure).

When producing an MRI image, contrast media (see: MRI with contrast media - is that dangerous?) Is usually used if there is a suspicion of a brain abscess. Magnetic resonance tomography (MRI of the head) has a higher diagnosis rate than computed tomography, especially in the early stage - abscess formation - and can therefore be used for early detection.

You might also be interested in this article: Abscess on the head

In addition to CT and MRT imaging, the examining doctor also has a special scintigraphy and the EEG (electroencephalogram) available for diagnosis.

therapy

in the Early stage of a brain abscess no capsule yet around the inflammation present. Therapy is therefore initially started with an intensive one Administration of antibiotics.
If a capsule has already formed around the brain abscess or if the disease process continues despite antibiosis, drug treatment is no longer sufficient. The brain abscess comes with a state-of-the-art surgical procedures (stereotactic puncture) punctured (punctured) with millimeter precision in order to achieve a Pressure relief to cause and on the other hand a drainageto lay a tubular drain for the pus.
The surgical removal of brain abscesses (total extinction) with Opening of the skull bone (Craniotomy) is only used at very superficial location considered, but can also be absolutely necessary if, for example, a foreign body (Bone fragments, metal part, etc.) is located in the abscess capsule. That can after a injury the case of the head.

Before and after any surgery, the patient is given antibiotics in high doses to prevent the inflammation from spreading and to kill the causative pathogens. If the antibiosis is not specifically tailored to the pathogen, three different antibiotics are usually used: Metronidazole, one Cephalosporin 3rd generation and an antibiotic against staphylococci like Methicillin or Vancomycin. Vancomycin is mainly used when a multi-resistant bacterial strain is suspected, on which many other antibiotics would not be effective.

Consequential damage

Since a brain abscess is a very invasive disease of the brain, 5 - 10% of patients die despite the best possible treatment. Especially those Pressure increase in the skull can become life threatening Entrapment of the midbrain or the brain stem - both are parts of the brain to the Control of vital processes.

If the disease is survived alive, as is the case with the majority of those affected, half of the patients recover completely. The duration of the healing process can vary from person to person.
The other half carries permanent damage from the brain abscess. These can result in ongoing symptoms, such as permanent Hemiparesis (Hemiplegia) or as failures in other brain regions where the abscess was sedentary. Through the increased intracranial pressurewhich is the diagnostically important Congestive papilla causes (description, see "Symptoms"), the optic nerve can be affected to the extent that it becomes so-called Visual field defects comes. These are visual disorders in which the image that the eye can perceive becomes smaller. The diagnosis of a visual field restriction is difficult, as the patient usually does not notice anything - he does not see any dark or black areas in his field of vision, simply no stimuli are passed on to the brain. Another consequence of a brain abscess that affects about a quarter of all patients is epileptic seizures. It comes to through the scar created by the healing Faults in the brain, within the framework of which the patient may suffer from epilepsy.