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Brain abscess (cerebral hemispheres, cerebellum)

Brain abscess (cerebral hemispheres, cerebellum)

Most brain abscesses located in the white matter of temporal lobe of the brain or in the cerebellum, in the vicinity of the affected temporal bone with otitis. Much rarer brain abscesses in the parietal, occipital, frontal lobe, in the pons legs of the brain, medulla and spinal cord and even on the side opposite the patient otitis ear (contralateral abscess).

Selected MRI images (T1 C+ axial) demonstrate a left cerebellar hemisphere lesion, which has high T2 signal centrally, and a thin relatively regular rim of contrast enhancement peripherally.

Causes of brain and cerebellum abscess

The cause of brain abscesses are traumatic and metastatic factor. Brain abscess occurs in 4-5 times more often in chronic purulent inflammation of the middle ear (otitis), than in acute otitis. In acute inflammation of the middle ear (otitis media), brain abscess may occur without perforation of the tympanic membrane (with negnoynom process), and emerge even after clinical cure of acute otitis media, normal otoskopicheskoy picture.

In chronic suppurative otitis media brain abscess occurs in the vast majority of cases when epitimpanitah and mezoepitimpanitah complicated by cholesteatoma. There may be cases of brain abscess and mezotimpanitah.

Most often, pus from an abscess of the brain are different types of streptococci, staphylococci, diplococcus, E. coli, anaerobes, Proteus, etc. Often, the pus from an abscess of the brain has a mixed flora. Flora identified in the pus at seeding of brain abscesses are not always identical detectable in secretions from the ear, due to accession to the microbe that caused inflammation of the ear, and other pathogens.

Factors contributing to the emergence of brain abscesses are lowering the body's resistance due to common infectious diseases, trauma, skull, especially the structure of the temporal bone (excessive pneumatization, especially the petrous part, presentation of sigmoid sinus, inferior position of the middle cranial fossa, etc.).

Pathway of infection of the temporal bone into the brain abscess in the brain are different. In abscess of the temporal lobe of the brain most often cited way to contact infection, which have some changes, until the destruction of the roof cavities of the middle ear (tympanic cavity or cave). The infection can spread to blood as a result of thrombosis of small veins tympanic cavity roof or thrombosis of the sinuses of the dura mater (transverse, cavernous, superior petrosal). Possible infection with abscess formation of the brain through the roof birth defects tympanic cavity or cranial sutures.

When cerebellar abscess infection spreads mainly from the affected labyrinth (chronic purulent otitis media) or thrombosed lateral (sigmoid sinus). When purulent labyrinth the infection can penetrate into the cerebellum after the destruction of the bone of the labyrinth (mostly posterior semicircular canal) on perilabirintnym cells (contact pathway) or preformed paths (vestibular aqueducts and the cochlea and internal auditory canal).

Selected MRI images (T2 axial) demonstrate a left cerebellar hemisphere lesion, which has high T2 signal centrally, and a thin relatively regular rim of contrast enhancement peripherally.

Abscesses are more rare in remote locations from the primary lesion in the temporal bone regions of the brain usually occur as a result of thrombosis of the transverse sinus. Further spread can be either a pin or by a retrograde move blood clots in small veins of the brain or by metastasis. In this way, there otogennye abscesses of the brain in the frontal, parietal and occipital lobes, as well as multiple and contralateral abscess.

In the propagation of infection from the temporal bone in the skull cavity outer layer of the dura mater, wherein the density and a rich blood supply, is very often difficult to overcome the barrier. In this connection, in most cases the process is limited to the development of epidural abscess and meningitis. Rarely extradural abscess is a stage of development of brain abscess.

Seam between the inner layer of the dura mater with a soft and arachnoid membrane and the latter with the substance of the brain prevent the spread of infection in the subarachnoid space and prevents the development of diffuse meningitis. The same union, especially when their vascularization, favor the spread of infection in the brain substance.

The most common way of infection in the brain - a venous (retrograde spread of infection by blood clots) or perivascular (through the lymph spaces surrounding the veins of the pia mater). Spread to the brain along the arteries is rare. In this case, there is thrombosis of the arteries with skid-infected emboli in the white matter of the brain. The introduction of pyogenic infection in the brain does not always lead to the formation of an abscess. Abscess of the brain occurs most often at lower immunobiological reactions.

Spread in brain arteries during rarely occurs. Thus there artery thrombosis skid infected embolus in the white matter of the brain.

The introduction of pyogenic infection in the brain does not always lead to the formation of an abscess. Brain abscess occurs more often at lower immuno-biological reactions.

 

Symptoms and clinical course of brain and cerebellum abscesses

Symptoms observed in abscess of the cerebral hemispheres and cerebellum are diverse and vary depending on the localization of the abscess, the reactions surrounding brain tissue, intracranial pressure, etc. Symptoms can be divided into:

  • toxical
  • cerebral
  • focal
  • distant

During otogenic brain abscesses to distinguish between primary, latent (latent), a clear and final (terminal) stage. Focal symptoms otogennogo abscess revealed in the explicit stage. Most often the initial stage goes unnoticed, is an obvious stage is sometimes absent. As a consequence, brain abscess is recognized sometimes very late, sometimes only on the operating table, or postmortem examination.

By toxic symptoms include pained facial expression (in later stages), weight loss, constipation, dry, coated tongue, a decrease or lack of appetite. Less commonly, an increased appetite (bulimia).

Selected MRI images (T1 C+ coronal) demonstrate a left cerebellar hemisphere lesion, which has high T2 signal centrally, and a thin relatively regular rim of contrast enhancement peripherally. Note the presence of dilatation of the occipital horns, consistent with hydrocephalus.

ESR increased in uncomplicated abscess (without concomitant meningitis or sepsis), leukocytosis, mild formula of white blood a little altered. Body temperature in uncomplicated brain abscesses are usually normal or low-grade, expressed increasing temperature episodic and variable.

Of the symptoms of brain abscess in the brain is the most constant headache. Headache is sometimes unbearable (at significant increased intracranial pressure). Headache is often diffuse in nature, but may be localized on the side of the abscess, and in abscess of the temporal lobe in the frontal or parietal-temporal region, and in abscess of the cerebellum more frequently in the neck or forehead.

Often, especially in abscess of the cerebellum, there is vomiting. Characterized by vomiting, "fountain" that occurs suddenly and out of touch with meals without anticipatory nausea.

Mostly clear in the stage of brain abscess, marked bradycardia. Changes in the fundus (stagnant nipples optic nerve) in brain abscesses are observed in almost half of patients and are usually combined with other expressions of brain or focal symptoms. Meningeal symptoms are frequent, they can be and uncomplicated brain abscesses.

In the cerebrospinal fluid (CSF) after lumbar puncture with uncomplicated abscesses observed a moderate increase in the amount of protein, sometimes slight CSF pleocytosis.

Stupefaction, confusion, excessive sleepiness, apathy - usually accompanied by a clear stage of brain abscess. From other mental disorders occur changes in the character, intellect, pathological distraction and forgetfulness. Patients reluctant and did not immediately respond to questions, showing an indifferent attitude to everything around him. Very rarely observed acute psychosis, systematized delusion, and other severe mental disorders.

When abscesses of the frontal lobe of the brain is often described unmotivated euphoria and excessive talkativeness patients.

Focal symptoms of an abscess of the temporal lobe of the brain as a sensory-amnestic aphasia are expressed only in the left-sided localization (in right-handers). Rarely a symptom of an abscess of the temporal lobe of the brain is hemianopsia (mainly homonymous with prolapse of both right and left halves of view), but spend a study rarely works.

Of the focal symptoms in abscess of the cerebellum should be noted spontaneous nystagmus, often directed towards the abscess. Such a direction of nystagmus is particularly of diagnostically valuable when you turn off the maze patient ear. By focal symptoms are also promahivanie with finger-pointing and nasal samples adiadohokinez become kinetic disorders in the form of deflection to one side or fall in the Romberg test, and walking (past impairments of the majority of patients due to severity of the condition can not be identified). Securities symptoms are disorders of muscle tone on the side of the brain abscess, and sometimes observed speech disorder in the form of dysarthria.

The so-called focal symptoms of an abscess of the cerebellum are essentially symptoms of the vestibular system primarily in the area of the pons and the medulla oblongata.

Paresis of limbs in abscess of the cerebellum are relatively rare and are on the side of the abscess. Paresis of cranial nerves (oculomotor, trigeminal, abducent, facial for peripheral type) are more common in complicated abscesses of the cerebellum.

Focal symptoms of cerebellar abscess is most often not expressed or detected too late. When abscesses right temporal lobe, parietal, occipital and other rare localisations focal symptoms often are absent.

Long-term symptoms of an abscess of the temporal lobe of the brain caused by the transfer pressure away from the abscess of the cerebrum, cerebellum, medulla oblongata, etc., or spread them edema, encephalitis. A number of patients with brain abscesses are marked symptoms of the pyramidal pathway (paresis, and paralysis of the limbs on the opposite side, the impairment of the sensitivity, abnormal reflexes), sometimes attacks of Jacksonian epilepsy, often paresis or paralysis of cranial nerves (oculomotor, facial for the central type, abducent, trigeminal, sublingual, rarely other nerves).

During brain abscess in most patients the initial stage in the form of short-term increase in temperature, chilling, diffuse headache, nausea does not cause suspicion. It is often regarded as a sharpening process in the ear, and sometimes not even attract the attention of any patient or doctor. Then follows a more or less prolonged period (latent stage) - at least up to a year or more, when the characteristic symptoms are not expressed, and these or other symptoms (often periodic, blurred headache) associated with the main process in the ear.

Go to the explicit stage occurs when a significant distribution of abscess or encephalitis zone with edema and swelling of the brain, leading to increased intracranial pressure. Appearing cerebral symptoms, but the focal symptoms are not always. Sometimes the obvious stage so quickly transferred to a terminal that a patient is admitted to the hospital in this state and operate.

The final stage of brain abscess is a consequence of progressive encephalitis, or brain edema and elevated intracranial pressure with compression and displacement of the brain stem, causing paralysis of the respiratory center. In some cases, the final stage occurs when the break abscess into the ventricles or subarachnoid space. Evolving with the meningitis has a rapid course and may in a short time (12-24 hours) lead to death.

 

Diagnosis of brain and cerebellum abscesses

Described the clinical picture of an abscess of the brain explains the difficulty of diagnosis in the absence of focal symptoms. In uncomplicated (meningitis or sepsis), a presumptive diagnosis of an abscess well-founded common grave condition of the patient in the presence of purulent process in the ear, a normal or slightly elevated temperature, severe headache, bradycardia.

Magnetic resonance imaging (MRI) performed for suspected brain abscess.

In patients with complicated abscesses of the clinical picture of meningitis covers symptoms of brain abscess, which is extremely difficult to diagnose. In the presence of focal symptoms diagnosis, of course, does not cause much difficulty. When reasonable suspicion to otogenny encephalopyosis diagnosis is during the operation (sometimes at the same time reveal the characteristic changes of the dura mater the middle and posterior cranial pits or even detect a fistula leading into the abscess cavity) with a puncture of the brain (temporal lobe or cerebellum).

When hidden, the "cold" abscess within the brain (mainly in cases of chronic encapsulated abscess without an apparent increase in intracranial pressure) is often successfully used - auxiliary diagnostic methods in the form:

Cerebral abscess stages:

Stage (age)
Histology highlights
CT and MRI
Resistance to aspiration
I – Early cerebritis
(up to 5 days)
Poorly demarcated inflammation CT: Thick ring enhancement
MRI: T1 hypo, T2 hyper
Slight
II – late cerebritis
(5 days – 2 weeks)
Developing necrotic center None
III – early capsule
(2-3 weeks)
Neovaskular reticular network surrounds CT: thin ring enhancement
MRI: T1 hypo – edema/center, hyper capsule, T2 – hyper edema, capsule and center restricted diffusion
None
IV – late capsule
( > 3 weeks)
Collagen capsule with surrounding gliosis Firm capsule

 

Treatment and prevention of brain and cerebellum abscess

If you suspect an abscess of the brain to operate in the temporal bone - a simple acute otitis media or obschepolostnuyu (radical) in chronic purulent otitis media. Produce a wide exposure of the dura mater in the middle or posterior fossa (sometimes dura mater is exposed pathological process, destroyed the shell adjacent to the bone), depending on operational findings and symptoms.

If the dura is not changed, and there are no focal symptoms and a sharp rise in intracranial pressure, from the puncture of the brain can temporarily refrain and follow closely in the coming days for postoperative symptom dynamics. Otherwise, make a puncture temporal lobe or cerebellum. When identifying an abscess surgery performed.

Treatment of brain abscesses may be closed (number of punctures with aspiration of pus and the introduction of antibiotics in its cavity) and open (wide open abscess after incision of the dura mater), followed by drainage of the cavity. Both methods otohirurgami, with best results obtained with the open method of treatment, providing better control over the abscess cavity and the best conditions for flight.

Neurosurgeons, based on the experience of treatment of traumatic and metastatic (not otogennyh), brain abscess, preferred approach to the abscess through the uninfected area - through the scales of the temporal bone (with abscess of the temporal lobe) or the occipital bone (with abscess of the cerebellum). With such an approach is not affected by anterior middle ear cavity, which is an absolute disadvantage. In addition, neurosurgeons often completely remove an abscess (together with the capsule, if present).

Neurosurgical treatment clearly shown at otogennyh multiple or contralateral abscesses, abscesses in the far distant from the primary tumor in the ear, and otogennyh abscesses with chronic and very dense capsule. In the vast majority of cases the best method of surgery is otiatrichesky open method, in which both removed a festering hotbed of the ear and widely expose the cavity of the brain abscess.

Postoperatively, antibiotics are based on antibiotikogrammy and sulfonamides, introduced as the intramuscular injection and tablets, and locally - in the abscess cavity. Apply dehydration therapy (if indicated), producing a plasma transfusion solutions. Provide thorough patient care, high-energy and fortified food (if required artificial nutrition), monitoring the physiological functions of the body. Despite the advances of surgical and conservative treatment, mortality in otogennyh brain abscesses are relatively high, as a result of delayed diagnosis.

Prevention of brain abscesses is early diagnosis and treatment of infectious diseases of the paranasal sinuses and the ear, the consequences of traumatic brain injury.