brain abscess

Brain abscess
A brain abscess is a neurological disease characterized by an accumulation of pus in the brain. The manifestations of this pathology are due to its localization in the brain. However, the signs of the disease are not specific, since they are characteristic of a wide variety of neurological pathologies.

The content of the article:
Etiology and pathogenesis of brain abscess
Stages of disease development
Clinical picture of brain abscess
The course of a brain abscess
Diagnosis of brain abscess
Differential diagnosis of brain abscess
Treatment of brain abscess
Prognosis for brain abscess
Prevention of brain abscess
Brain abscess
The disease is detected using diagnostic techniques such as magnetic resonance imaging and computed tomography of the brain. If during the diagnosis the patient has a minimal accumulation of pus in the brain, the doctor prescribes conservative treatment. Large abscesses that provoke sharp jumps in intracranial pressure need surgical treatment.

An important place in the treatment of a brain abscess is occupied by its timely diagnosis, which provides for the definition of the type of disease. In neurology, an extensive classification of the disease is used. Depending on the place of accumulation of pus in the brain, an abscess of the cerebellum, temporal region, frontal region, occipital lobe and parietal lobe is isolated. Depending on the purulent accumulation relative to the membranes of the brain, there are such types of abscess as intracerebral, subdural, epidural and periventricular.

Depending on the development of the disease, there are four stages of it: initial, latent, explicit and terminal. According to the etiology of the disease , the following forms are distinguished:

abscesses that are provoked by traumatic brain injuries;
rhinogenic abscesses that have arisen due to purulent sinusitis, pharyngitis, rhinitis;
metastatic abscesses caused by complications of various diseases;
otogenic abscesses as a result of purulent otitis, mastodon;
abscesses due to sterility disorders during intravenous administration of medications.
Etiology and pathogenesis of brain abscess
The cause of a brain abscess is most often an inflammatory process due to the activity of streptococci. With the otogenic nature of the disease, its pathogens are enterobacteria. In the case of an open brain injury, staphylococci can provoke the accumulation of pus. In more than 30% of cases of the disease, it is impossible to establish its exact cause, since laboratory tests of pus show its sterility.

Inflammatory process
The most common cause of the disease is considered to be an inflammatory process that is activated in organs and tissues. For example, inflammations such as pleural empyema, chronic and acute pneumonia may occur in the lungs. Infection of the brain occurs due to the ingestion of an infected blood clot through the blood vessels.

Brain injuries
Often the cause of the disease is open or closed brain injuries. Infection in this case occurs due to the ingress of staphylococci into the wound. In rare cases, an abscess may occur in a patient after a severe neurosurgical operation. Patients with purulent forms of sinusitis, sinusitis, frontitis, otitis media are also at risk. In such cases, the causative agent of infection can enter the brain in two ways: through the veins of the brain or through its hard shell.

Stages of disease development
The pathogenesis of a brain abscess involves four stages of its development:

Early inflammation of the brain (1-3 days). The patient has the development of encephalitis — a limited inflammation of brain tissues. It is important that at this stage it is still quite possible to reverse the disease. The inflammatory process may end spontaneously or at the end of antibacterial therapy.
Late stage (4-9 days). This stage occurs in the case of weakened protective functions of the patient’s body or due to incorrectly chosen treatment tactics. Therefore, the inflammation begins to progress — the cavity filled with pus begins to increase in size.
Early encapsulation (10-13 days). This stage of inflammation is characterized by necrosis of the central part of the brain, as well as the formation of a capsule that limits the further spread of pus.
Late encapsulation (starting from day 14). Starting from the second week after the activation of the inflammatory process, the patient is diagnosed with a clear collagen capsule filled with pus and surrounded by a gliosis zone. The further development of inflammation depends on the reactivity of the patient’s body, the virulence of the flora, and proper treatment. Often at this stage there is an increase in the volume of purulent content and the formation of new foci of inflammation.
Clinical picture of brain abscess
There are the following signs of a brain abscess: general infectious, cerebral and focal.

General infectious signs
Common manifestations of the disease include fever, increased ESR, chills, leukocytosis, as well as signs of an infectious process such as weight loss, pallor or weakness.

General cerebral symptoms
General cerebral symptoms occur due to sudden jumps in intracranial pressure. The most common symptom of pathology is headache, accompanied by vomiting. The patient may have problems with vision: often, optic neuritis develops against the background of an abscess, and stagnant discs appear on the fundus. The clinical picture of the disease also includes mental disorders, inhibition of thought processes, lethargy, weakness, apathy. In the case of intracranial hypertension, epileptic seizures may occur. Most patients also experience constant drowsiness, and in the most severe cases, coma may occur.

Focal signs
Focal signs of the disease depend largely on the localization of the abscess. For example, if pus accumulates in the depths of the cerebral hemispheres outside the motor zone, the disease can proceed without specific symptoms. If the patient has an accumulation of pus located too close to the membranes of the brain or is located in the cerebellum, meningeal symptoms appear.

The course of a brain abscess
As for the course of the disease, it often has a very violent and acute onset, which is characterized by focal and hypertensive manifestations. The inflammatory process almost always develops against the background of an elevated temperature. In rare cases, the onset of the disease may be less pronounced and resemble the clinical picture of meningitis. However, with minimal symptoms and a normal temperature, the first stage of the disease is extremely rare.

After 5-30 days, the disease passes into the next, latent, stage, which is characterized by either the complete absence of any symptoms, or minimally pronounced signs of the disease. The patient may complain of severe and regular headache, mental retardation and vomiting. The duration of this stage is variable: in some patients it lasts a couple of days, while in others it lasts several years. Then, due to the influence of some factor (for example, infection), this stage ends and the patient’s symptoms begin to actively progress. The most severe and life-threatening consequence of a brain abscess is considered to be its breakthrough, which usually leads to death.

Diagnosis of brain abscess
Timely comprehensive diagnosis of a brain abscess is important in its further treatment. To make a diagnosis, a neurologist uses anamnesis data and the results of the patient’s examination, as well as information obtained during instrumental and laboratory studies. The following methods are used to diagnose the disease:

A general blood test. The disease is usually indicated by such analysis results as an increase in ESR and pronounced leukocytosis. At the stage of capsule formation around the abscess, a normal or slightly increased number of white blood cells is observed in the patient’s blood.
Computed tomography. The accuracy of detecting an abscess using this technique depends on the stage of pathology. In the early stages, an abscess is very difficult to detect. At the stage of encephalitis, CT can reveal a zone of reduced density, having an uneven shape. At this stage, the contrast agent accumulates unevenly — often only in the peripheral parts. It is much more accurate to diagnose the disease at a late stage of encephalitis development.
Magnetic resonance imaging. This is a more accurate and effective method of diagnosing an abscess, which allows you to identify it at an early stage. Since the technique is considered the most informative, according to its results, treatment can be prescribed even without bacteriological tests.
Echoencephaloscopy. This diagnostic method is usually prescribed if, for some reason, MRI and CT cannot be performed. With the help of this study, it is possible to detect a displacement of brain structures, which indicates compression of its tissues by an abscess.
Bacteriological research. This technique involves taking a puncture of pus from an abscess for its examination. A detailed study of pus helps to establish the causative agent of inflammation, which then allows you to choose the most appropriate tactics of drug therapy.
Radiography of the skull. This technique is used to detect the source of infection that provoked the abscess.
Craniography. It is prescribed to detect symptoms of intracranial hypertension.
Differential diagnosis of brain abscess

Since most of the symptoms of a brain abscess are not specific, differential diagnosis plays an important role. If the doctor has doubts during the diagnosis, he can prescribe MR spectroscopy. This technique is carried out in order to differentiate a brain abscess from tumors of the cerebral hemispheres. It is based on the different content of lactate and amino acids in tumors and purulent accumulation.

As for other diagnostic methods, they are considered less informative. For example, signs such as an increase in C-reactive protein in the blood, chills, an increase in ESR, leukocytosis may indicate a variety of inflammatory processes. Blood cultures with an abscess often turn out to be sterile.

Treatment of a brain abscess Treatment of a brain abscess usually involves both drug therapy and surgery. Doctors make the choice of the most optimal treatment tactics based on the results of the diagnosis of the disease, as well as the general state of health of the patient. The stage of the disease is also taken into account. For example, in the early stages of abscess formation, conservative treatment can be dispensed with. If the abscess has already formed, and a dense capsule has formed around it, you cannot do without neurosurgical intervention.

Medical treatment
Medical treatment of brain abscess involves the appointment of antibiotics, decongestants and anticonvulsants. Since the inflammatory process is provoked by bacteria, the therapy of the disease necessarily provides for their destruction. The combination of penicillin and chloramphenicol has been considered the most standard and frequently used treatment regimen for brain abscess for decades.

Penicillin was prescribed for the treatment of the disease, because it is able to destroy streptococci and most other bacteria that can provoke a brain abscess. Chloramphenicol was used because of its ability to easily dissolve in adipose tissue and destroy anaerobic bacteria.

Today, doctors are slightly correcting this scheme. For example, cefotaxime is prescribed instead of penicillin, and metronidazole is prescribed instead of chloramphenicol. Usually, the doctor prescribes antibacterial therapy a few weeks before the operation. The duration of taking antibiotics can be about 6-8 weeks.

Patients who have a brain abscess that occurs against the background of immunodeficiency are also prescribed amforeticin. If the abscess has disappeared, the patient will have to undergo a course of fluconazole for ten weeks. Drugs such as sulfadiazine and pyrimethamine are usually present in the treatment regimen of HIV patients.

Of great importance in the treatment of the disease is the correct determination of the causative agent of infection using an antibioticogram. However, there are cases when the sowing turns out to be completely sterile. Therefore, empirical antibacterial therapy is prescribed in such situations.

In addition to antibiotics, medications that help reduce swelling are also prescribed. For example, glucocorticoids are used for this purpose. However, the appointment of these drugs is indicated only in the case of a positive result from antibacterial therapy. They can reduce the severity of a brain abscess and reverse the development of a capsule around it. However, the opposite effect is also possible, when glucocorticoids activate the spread of inflammation beyond the boundaries of the focus. To eliminate convulsive manifestations, phenytoin is usually prescribed.

Surgical treatment
If a brain abscess is diagnosed at late stages, and a dense capsule has already formed around it, it is impossible to do without surgery. For the treatment of the disease, puncture aspiration and abscess removal are most often used.

As for puncture aspiration, it is advisable to prescribe it at the early stages of pathology. At the same time, antibacterial therapy should be carried out at the same time. Indications for this procedure may also be multiple abscesses, a deep location of the abscess, a stage of cerebritis and a stable neurological condition of the patient. In order for the procedure to be performed as accurately as possible, the doctor resorts to stereotactic biopsy and intraoperative ultrasound.

Puncture aspiration has one important drawback — in most cases, a repeat procedure may be required after it is performed. In difficult cases, a complete removal of the abscess is prescribed. This technique is also prescribed if they want to avoid a possible recurrence of the disease. It is advisable to remove the abscess with the following indications: if antibacterial therapy or puncture aspiration did not prove effective, with a superficial abscess and a well-formed capsule around it.

If multiple abscesses were found in the patient during the diagnosis, in this case, first you need to drain the focus of inflammation to exclude the breakthrough of pus into the ventricular system of the brain. In case of an increase in neurological disorders or the absence of positive dynamics during MRI and CT, a repeat operation may be prescribed.

Prognosis for brain abscess
The outcome of the disease depends on whether the doctor was able to identify the causative agent of the abscess from the sowing. It is extremely important to do this, because then it will be possible to determine the sensitivity of bacteria to antibiotics and choose the most appropriate therapy regimen. The prognosis for the health of a patient with a brain abscess also depends on the number of purulent accumulations, the patient’s state of health, and the right treatment tactics.

The risk of various complications in brain abscess is very high. Namely, about 10% of all cases of the disease end in death, and 50% — disability. In addition, most patients may develop epileptic syndrome after the end of treatment, a condition characterized by the occurrence of epileptic seizures.

Doctors give less favorable forecasts to patients who have been found to have subdural empyema. In this case, the patient does not have a clear border of the purulent focus due to the high activity of the pathogen of infection or insufficient resistance of the body to it. Fatal cases with subdural empyema reach 50%.

The most dangerous form of brain abscess is considered to be fungal empyema, which is accompanied by immunodeficiency. Such a disease is practically not treated, and the number of deaths with it is about 95%. In turn, epidural empyema has a more favorable prognosis and is almost never accompanied by complications.

Prevention of brain abscess
There are no effective methods to prevent brain abscess. Nevertheless, with the help of several preventive measures, it is possible to significantly reduce the risk of the disease. In particular, in the case of a traumatic brain injury, the patient should receive adequate surgical care.

Timely elimination of foci of infection (pneumonia, boils), treatment of purulent processes in the inner and middle ear, as well as the paranasal sinuses will also help prevent the disease. Good nutrition also plays a great role in the prevention of brain abscess.

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