Abscess of a brain is a limited congestion of pus in a skull cavity. Distinguish three types of abscesses: intracerebral, subduralny and epiduralny. Symptoms of abscess of a brain depend on its location and the sizes. They are not specific and can make clinic of any volume education. Brain abscess according to brain KT or MPT is diagnosed. At abscesses of the small size are subject to conservative treatment. The abscesses located near brain ventricles, and also causing sharp rise in intra cranial pressure demand surgical intervention, at impossibility of its carrying out - a stereotaksichesky puncture of abscess.
Abscess of a brain is a limited congestion of pus in a skull cavity. Distinguish three types of abscesses: intracerebral (a pus congestion in brain substance); subduralny (located under a firm brain cover); epiduralny (localized over a firm brain cover). The main ways of penetration of an infection to a cavity of a skull are: hematogenic; the open getting craniocereberal trauma; pyoinflammatory processes in additional bosoms of a nose, a middle and inner ear; infection of a wound after neurosurgical interventions.
Most often inflammatory processes in lungs (a bronkhoektatichesky disease, an empiyema of a pleura, chronic pneumonia, lung abscess) are the reason of formation of hematogenic abscesses of a brain. In such cases the fragment of the infected blood clot (from a vessel on the periphery of the inflammatory center) which will get to a big circle of blood circulation becomes a bacterial embol and by a stream of blood it is carried in brain vessels where it is fixed in small vessels (a prekapillyara, a capillary or the arteriol). In pathogenesis of abscesses the bacterial endocarditis, infections of a GIT and sepsis can be of little importance chronic (or sharp).
In case of the open getting craniocereberal trauma abscess of a brain develops owing to direct hit of an infection in a skull cavity. In peace time the share of such abscesses makes 15-20%. In the conditions of fighting it increases many times (mine and explosive wounds, gunshot wounds).
At pyoinflammatory processes in additional bosoms of a nose (sinusitis), a middle and inner ear two ways of spread of an infection are possible: retrograde — on sine of a firm brain cover and brain veins; and direct penetration of an infection through a firm cover of a brain. In the second case the delimited inflammation center originally is formed in brain covers, and then — in adjacent department of a brain.
The brain abscesses which are formed against the background of intrakranialny infectious complications after neurosurgical interventions (ventrikulita, meningitis) arise, as a rule, at the heavy, weakened patients.
Among the allocated causative agents of hematogenic abscesses of a brain streptococci prevail, it is frequent in association from bakteriotida (Bacteroides spp.). Enterobacteriaceae are characteristic of hematogenic and otogenny abscesses (including Proteus vulgaris). At the open getting craniocereberal trauma in pathogenesis of abscess of a brain prevail staphylococcus (St. aureus), Enterobacteriaceae is more rare. At various immunodeficiency (immunosuppressive therapy after organ and tissue transplantation, HIV infection) from crops of contents of abscess of a brain allocate Aspergillus fumigatus. However it is not possible to identify the causative agent of an infection in brain abscess contents quite often as in 25-30% of cases crops of contents of abscess are sterile.
Formation of abscess of a brain takes place in several stages.
- 1-3 days. The limited inflammation of brain fabric — encephalitis develops (early tserebrit). At this stage inflammatory process is reversible. Perhaps as its spontaneous permission, and under the influence of antibacterial therapy.
- 4-9 days. As a result of insufficient protective mechanisms or in case of incorrect treatment inflammatory process progresses, in its center the cavity filled with pus capable to increase.
- 10-13 days. At this stage around the purulent center the protective capsule is formed of connecting fabric which interferes with distribution of purulent process.
- Third week. The capsule is finally condensed, around it the zone of a glioz is formed. Further development of the situation depends on virulence of flora, reactivity of an organism and adequacy of medical and diagnostic actions. Perhaps return development of abscess of a brain, but is more often increase in its internal volume or formation of the new centers of an inflammation on the periphery of the capsule.
Brain abscess symptoms
Today the patognomonichny symptomatology is not revealed. The clinical picture at abscesses of a brain is similar to a clinical picture of volume education when clinical symptoms can vary from a headache to the hardest all-brain symptoms interfaced to oppression of consciousness and the expressed focal symptoms of damage of a brain. In certain cases the epileptiformny attack becomes the first display of a disease. Meningealny symptoms (can be observed at subduralny processes, an empiyema). Epiduralny abscesses of a brain often are associated with osteomyelitis of bones of a skull. Progrediyentny increase of symptomatology is observed.
For diagnosing of abscess of a brain huge value has careful collecting the anamnesis (existence of the centers of a purulent infection, the sharp infectious beginning). Existence of the inflammatory process interfaced to emergence and aggravation of neurologic symptoms — the basis for additional neurovisualization inspection.
Diagnosing accuracy by means of KT of a brain depends on a stage of formation of abscess. At early stages of a disease diagnostics is complicated. At a stage of early encephalitis (1-3 days) KT defines a zone of the reduced density of irregular shape. The entered contrast substance collects unevenly, mainly peripheral departments of the center, is more rare in the center. At later stages of encephalitis contours of the center get equal roundish outlines. Contrast substance is distributed evenly, on all periphery of the center; density of the central area of the center at the same time does not change. However on repeated KT (in 30-40 minutes) diffusion of contrast in the center of the capsule, and also existence it and in a peripheral zone is defined that it is not characteristic of malignant new growths.
The encapsulated brain abscess on KT has an appearance of roundish volume education with accurate equal contours of the increased density (the fibrous capsule). In the center of the capsule the zone of the lowered density (pus), on the periphery is visible a hypostasis zone. The entered contrast substance collects in the form of a ring (on a contour of the fibrous capsule) with a small contiguous zone of a glioz. On repeated KT (in 30-40 minutes) contrast substance is not defined. At a research of results of a computer tomography it is necessary to consider that anti-inflammatory medicines (glucocorticosteroids, salycylates) substantially influence a contrast congestion in the entsefalitichesky center.
Brain MRT — more exact method of diagnosing. When carrying out MRT at the first stages of formation of abscess of a brain (1-9 days) the entsefalitichesky center looks: on the T1-weighed images — hypointensive, on the T2-weighed images — hyper intensive. MRT at the late (encapsulated) brain abscess stage: on the T1-weighed images abscess looks as a zone of the lowered signal in the center and on the periphery (in a hypostasis zone), and on a capsule contour a signal hyper intensive. On the T2-weighed images the center of abscess from - or hypointensive, in a peripheral zone (a hypostasis zone) hyper intensive. The contour of the capsule is accurately outlined.
Differential diagnosis of abscess of a brain has to be carried out with primary glial and metastatic tumors of hemispheres of a brain. At doubts in the diagnosis it is necessary to carry out MZ-spectroscopy. In that case differentiation will be based on various content of amino acids and a lactate in tumors and abscesses of a brain.
Different ways of diagnostics and differential diagnosis of abscess of a brain of a maloinformativna. Increase in SOE, the increased content of S-jet protein in blood, , fever — simptomokompleks practically any inflammatory processes, including intra cranial. Bakposev of blood at brain abscesses in 80-90% are sterile.
Treatment of abscess of a brain
At an entsefalitichesky stage of abscess (the anamnesis – up to 2 weeks), and also in case of small abscess of a brain (to 3 cm in the diameter) conservative treatment which basis has to be an empirical antibacterial therapy is recommended. Carrying out a stereotaksichesky biopsy for final verification of the diagnosis and allocation of the activator is in certain cases possible.
The abscesses causing dislocation of a brain and increase in intra cranial pressure, and also localized in a zone of ventricular system (hit of pus in ventricular system often leads to lethal outcomes) — absolute indications to surgical intervention. The traumatic abscesses of a brain located in a zone of a foreign matter also are subject to surgical treatment as this inflammatory process will not respond to conservative treatment. Despite the adverse forecast, fungal abscesses are also the absolute indication to surgical intervention.
Contraindication to surgical treatment are the brain abscesses located in the vital and deep structures (a visual hillock, a brain trunk, subcrustal kernels). In such cases carrying out a stereotaksichesky method of treatment is possible: a puncture of abscess of a brain and its depletion with the subsequent washing of a cavity and introduction of antibacterial medicines. Perhaps both single, and repeated (through the catheter established for several days) washing of a cavity.
Serious somatic illness is not an absolute contraindication to performing surgical treatment as stereotaksichesky operation can be performed also under local anesthesia. Critical condition of the patient (a terminal coma) as in such cases any surgery is contraindicated can only be an absolute contraindication to carrying out operation.
The purpose empirical (in lack of crops or at impossibility of allocation of the activator) antibacterial therapy is the covering of the greatest possible range of activators. In case of brain abscess without craniocereberal trauma or neurosurgical intervention the following algorithm of treatment is shown in the anamnesis: ; tsefalosporina of the III generation (tsefotaksy, , tsefiksy); metronidazole. In case of post-traumatic abscess of a brain metronidazole is replaced with rifampicin.
The causative agent of abscess of a brain at patients with immunodeficiency (except HIV) most often is Cryptococcus neoformans, Candida spp or Aspergillius spp is more rare. Therefore in these cases appoint In or liposomalny V. V a case appoint disappearance of abscess (according to neyroviualizatsionny researches) within 10 weeks, subsequently reduce a dose twice and leave as supporting. At patients with HIV the causative agent of abscess of a brain most often is Toxoplasma gondii therefore empirical treatment of such patients has to include with pirimetaminy.
After allocation of the activator from crops treatment needs to be changed, considering an antibiotikogramma. In case of sterile crops it is necessary to continue empirical antibacterial therapy. Duration of intensive antibacterial therapy — not less than 6 weeks, after that is recommended to replace antibiotics with oral and to continue treatment of 6 more weeks.
Purpose of glucocorticoids is justified only in case of adequate antibacterial therapy as only at the positive forecast glucocorticoids can cause reduction of expressiveness and the return development of the capsule of abscess of a brain. In other cases their application can cause distribution of inflammatory process out of limits of primary center.
The main methods of surgical treatment of intracerebral abscesses are simple or pritochno-ottochny drainage. Their essence consists in installation in a cavity of abscess of a catheter through which evacuation of pus with the subsequent introduction of antibacterial medicines is carried out. Installation of the second catheter of smaller diameter (for several days) through which infusion of solution for washing is carried out is possible (most often, 0,9% of solution of chloride of sodium). Drainage of abscess needs to be accompanied with antibacterial therapy (at first empirical, further — taking into account sensitivity to antibiotics of the allocated pathogen).
Stereotaksichesky aspiration of contents of abscess without installation of a drainage — an alternative method of surgical treatment of abscess of a brain. Its main advantages — indulgent requirements to qualification of medical staff (close attention and special knowledge are necessary for control over functioning of pritochno-ottochny system) and smaller risk of secondary infection. However in 70% of use of this method there is a need of repeated aspirations.
In case of multiple abscesses of a brain it is necessary to drain first of all the center, the most dangerous concerning complications (break of pus in ventricular system, dislocation of a brain), and also the most significant in a clinical picture. In case of an empiyema or subduralny abscess of a brain apply drainage, without using pritochno-ottochny system.
The forecast at brain abscess
In forecasting of abscesses of a brain an opportunity to allocate the activator from crops and to define its sensitivity to antibiotics is of great importance, only in this case performing adequate pathogenetic therapy is possible. Besides, the outcome of a disease depends on quantity of abscesses, reactivity of an organism, adequacy and timeliness of medical actions. Percent of lethal outcomes at brain abscesses — 10%, invalidizations — 50%. Almost a third of the survived patients has a consequence of a disease an epileptic syndrome.
At subduralny empiyema forecasts are less favorable due to the lack of borders of the purulent center, so it testifies high virulence of the activator, or to the minimum resilience of the patient. A lethality in such cases — to 50%. Fungal empiyema in combination with immunodeficiency in most cases (to 95%) lead to a lethal outcome. Epiduralny empiyema and abscesses of a brain usually have the favorable forecast. Penetration of an infection through the intact firm brain cover is almost excluded. Sanitation of the osteomiyelitichesky center allows to eliminate an epiduralny empiyema. Timely and adequate treatment of primary purulent processes, and also full preprocessing of wounds at ChMT allow to lower a possibility of development of abscess of a brain substantially.