CEREBRAL CIRCULATION — blood circulation on system of vessels of a brain. Blood supply of a brain more intensively, than any other bodies: apprx. 15% of the blood coming to a big circle of blood circulation at cordial emission proceeds on blood vessels of a brain (the weight makes it only 2% of the body weight of the adult). Extremely high brain blood stream provides the greatest intensity of metabolic processes in tissue of a brain. Such blood supply of a brain is supported and during sleep. In a brain also the fact that 20% of the oxygen absorbed from the environment are consumed by a brain and it is used on the oxidizing processes proceeding in it demonstrates to metabolic rate.
- 1 PHYSIOLOGY
- 2 METHODS of the RESEARCH of the BRAIN BLOOD-GROOVE
- 3 PATHOLOGICAL PHYSIOLOGY
- 4 PATHOLOGICAL ANATOMY of FRUSTRATION of CEREBRAL CIRCULATION
- 5 PATHOLOGY
The circulatory system of a brain provides perfect regulation of blood supply of its fabric elements, and also compensation of disturbances of a brain blood-groove. Brain (see) the person it is supplied with blood at the same time four main arteries — pair internal sleepy and vertebral, to-rye are combined among themselves by a wide anastomosis in the field of an arterial (villiziyev) circle of a great brain (tsvetn. fig. 4). In normal conditions blood does not mix up here, arriving ipsilateralno from each internal carotid artery (see) in hemicerebrums, and from vertebrata — it is preferential in the departments of a brain located in the field of a back cranial pole.
Brain arteries are vessels not of elastic, but muscular type with a plentiful adren-and a cholinergic innervation therefore, changing the gleam over a wide range, they can participate in regulation of blood supply of a brain.
The pair front, average and back brain arteries departing from an arterial circle, branching and anastomosing among themselves, form the complex system of arteries of a soft meninx (pialny arteries) having a number of features: branchings of these arteries (up to the smallest, to dia. 50 microns and less) are located on the surface of a brain and regulate blood supply of extremely small areas; each artery lies in rather wide canal of subarachnoid space (see. Meninx ), and therefore its diameter can change over a wide range; arteries of a soft meninx lie over the anastomosing veins. The radial arteries branching in the thickness of a brain depart from the smallest arteries of a soft meninx; they have no around walls of the free space and, according to experimental data, are least active from the point of view of change of diameter at M.'s regulation to. An interarterial anastomosis in the thickness of a brain is absent.
A capillary network in the thickness of a brain continuous. Its density of subjects is more, than more intensively a metabolism in fabrics therefore in gray matter it is much more dense, than in white. In each part of a brain the capillary network is characterized by specific very tectonics.
A venous blood comes from capillaries of a brain to widely anastomosing venous system as soft meninx (pialny veins), and to a big brain vein (Galen's vein). Unlike other parts of a body the venous system of a brain does not perform capacity function.
In more detail anatomy and histology of blood vessels of a brain — see. Brain .
Regulation of cerebral circulation is carried out by perfect physiological system. Effectors of regulation are the main, intracerebral arteries and arteries of a soft meninx, to-rye are characterized specific funk. features.
Four types of regulation of M. to. are represented on the scheme.
At change of level of the general ABP in certain limits intensity of a brain blood-groove remains to a constant. Regulation of a constant blood-groove in a brain at fluctuations of the general ABP is carried out thanks to change of resistance in arteries of a brain (cerebrovascular resistance), to-rye are narrowed at increase in the general ABP and extend at his decrease. Originally assumed that vascular shifts are caused by reactions of unstriated muscles of arteries to different degree of stretching of their walls intravascular pressure. This type of regulation received the name of an autoregulyation or self-control. Level of the raised or lowered ABP, at Krom a brain blood stream stops being to constants, call respectively the upper or lower bound of an autoregulyation of a brain blood-groove. Experimental and the wedge, works showed that the autoregulyation of a brain blood-groove is in close interrelation with neurogenic influences, to-rye can displace top and bottom borders of its autoregulyation. Effectors of this type of regulation in arterial system of a brain are the main arteries and arteries of a soft meninx, active reactions to-rykh support a constant blood stream in a brain at change of the general ABP.
M.'s regulation to. at change of gas composition of blood is that the brain blood stream amplifies at increase in maintenance of CO 2 and at reduction of maintenance of O 2 in an arterial blood also decreases at their return ratio. Influence of blood gases on a tone of arteries of a brain, according to a number of authors, can be carried out in the humoral way: at hypercapnias (see) and hypoxias (see) concentration of H increases in tissue of a brain + , the ratio between HCO changes 3 - and CO 2 , what together with others biochemical, shifts in extracellular liquid directly influences metabolism of unstriated muscles, causing dilatation) arteries. An important role in operation of these gases on vessels of a brain is played also by the neurogenic mechanism, in Krom chemoceptors of a carotid sine and, apparently, other brain vessels participate.
Elimination of excess volume of blood in vessels of a brain is necessary since the brain is located in a bottletight skull and its excessive krovenapolneniye leads to increase intracranial pressure (see) and to a prelum of a brain. The excess volume of blood can arise at difficulty of outflow of blood from veins of a brain and at excess inflow of blood owing to an arteriectasia of a soft meninx, napr, at asphyxia (see) and at a post-ischemic hyperemia (see. Hyperemia ). There are data that effectors of regulation at the same time are the main arteries of a brain, to-rye are narrowed reflex owing to irritation of baroreceptors of brain veins or arteries of a soft meninx and limit inflow of blood to a brain.
Regulation of adequate blood supply of tissue of brain provides compliance between intensity of a blood-groove in system microcirculation (see) and metabolic rate in tissue of a brain. This regulation takes place at change of metabolic rate in tissue of a brain, napr, sharp strengthening of its activity, and at primary change of inflow of blood to tissue of a brain. Regulation is carried out locally, and its effector are small arteries of a soft meninx, to-rye exercise control of a blood-groove in is insignificant small sites of a brain; the role at the same time of smaller arteries and arterioles in the thickness of a brain is not established. Management of a gleam of arteries effectors at regulation of a brain blood-groove, according to most of authors, is carried out in the humoral way, i.e. at direct action of the metabolic factors collecting in tissue of a brain (hydrogen ions, potassium, adenosine). Nek-ry experimental data confirm the neurogenic mechanism (local) of a vazodilatation in a brain.
Types of regulation of cerebral circulation. Regulation of a brain blood-groove at change of level of the general arterial pressure (III) and at an excess krovenapolneniye of vessels of a brain (IV) is carried out by the main arteries of a brain., At change of the oxygen content and carbon dioxide gas in blood (II) and at disturbance of adequacy of blood supply of tissue of brain (I) regulation joins small arteries of a soft meninx.
METHODS of the RESEARCH of the BRAIN BLOOD-GROOVE
the Method of Ket — Schmidt allows to determine a blood stream in the whole brain of the person by means of measurement of speed of a saturation (saturation) of tissue of brain by inert gas (usually after inhalation of small amounts of nitrous oxide). Saturation of tissue of brain is established by definition of concentration of gas in tests of the venous blood taken from a bulb of a jugular vein. This method (quantitative) allows to define an average blood stream of the whole brain only discretely. It was established that intensity of a brain blood-groove at the healthy person is equal to about 50 ml of blood on 100 g of tissue of brain in 1 min.
The clinic uses the direct method allowing to obtain quantitative data on a brain blood-groove in small areas of a brain by means of clearance (speed of clarification) of radioactive xenon ( 133 Xe) or gaseous hydrogen. The principle of a method is that tissue of a brain is saturated with easily diffusing gases (solution 133 Xe usually enter into an internal carotid artery, and inhale hydrogen). Determine the speed of clarification of tissue of brain from gas by the corresponding detectors (for 133Xe they are established over the surface of an intact skull, for hydrogen platinum or gold electrodes enter into any areas of a brain), edges it is proportional to intensity of a blood-groove.
The method of definition of changes of volume of blood in superficially located vessels of a brain with radionuclides belongs to straight lines (but not quantitative) to methods, to-rymi mark proteins of a blood plasma; at the same time radionuclides do not diffuse through walls of capillaries in fabric. Special distribution was gained marked a radioiodine by albumine of blood.
Rheoencephalography (see) — eurysynusic kosven ny method of a research of a brain blood-groove. Define by the electrodes attached to the surface of a skull conductivity of edge, in turn, depends the otkrovenapolneniye of vessels changing at each pulse wave. Registering this parameter continuously, do the conclusion about a blood-groove and a condition of walls of vessels of a brain.
the Basic structural elements of a brain — neurocytes — are the most sensory cells of an organism to disturbances of blood supply. The blood-groove in tissue of a brain completely suffices to stop for several seconds that function of neurocytes was broken; in a few minutes in them there occur irreversible changes. Circulator disturbances are the most frequent reason of various defeats of function of a brain.
Disturbances of a brain blood-groove consist hl. obr. in patol, changes of its intensity (easing or strengthening), to-rykh changes of arteriovenous swing pressure and resistance in vessels of a brain are the most frequent reasons (see. Hemodynamics ).
Reduction of arteriovenous swing pressure owing to decrease in the general ABP or increase in the general is the reason of decrease in intensity of a brain blood-groove venous pressure (see), at the same time the major role is played by arterial hypotension (see. Hypotension arterial ). The general the ABP can sharply go down, and the general venous pressure increases less often and less considerably. Reduction of intensity of a brain blood-groove can be caused also by increase in resistance in vessels of a brain that can depend on such reasons as atherosclerosis (see), thrombosis (see) or vasomotor spasm (see) these or those of arteries of a brain. Decrease in intensity of a brain blood-groove can depend on intravascular aggregation of uniform elements of blood (see. Aggregation of erythrocytes ). Arterial hypotension, weakening a blood stream in all brain, causes the greatest decrease in its intensity in so-called zones of adjacent blood supply where intravascular pressure falls most strongly. During the narrowing or occlusion of separate arteries of a brain the expressed changes of a blood-groove are observed in the center of pools of the corresponding arteries. Are of great importance at the same time secondary patol, changes in vascular system of a brain, napr, change of reactivity of brain arteries at ischemia (konstriktorny reactions in response to vazodilatatorny influences), not recovered blood stream.v tissues of a brain after ischemia or a spasm of arteries in the field of an ekstravazation of blood, in particular subarachnoidal hemorrhages. The increase in venous pressure in a brain playing less significant role in easing of intensity of a brain blood-groove can have independent value when it is caused, in addition to increase in the general venous pressure, the local reasons leading to difficulty of outflow of a venous blood from a skull (thrombosis or a tumor). At the same time there are phenomena of venous stagnation of blood in a brain, to-rye lead to the increase in a krovenapolneniye of a brain promoting increase in intracranial pressure (see. Hypertensive syndrome ) and to edematization of a brain (see. Swelled also swelling of a brain ).
Patol, strengthening of intensity of a brain blood-groove can depend on increase in the general ABP (see. arterial hypertension ) also it can be caused by primary dilatation (patol, a vazodilatation) arteries; then it occurs only in those areas of a brain where arteries are expanded. Patol, increase in intensity of a brain blood-groove can lead to increase in intravascular pressure. If walls of vessels are patholologically changed (see. Arteriosclerosis ) or there are arterial aneurisms, that sudden and sharp increase in the general ABP (see. Crises ) can lead to hemorrhage. Patol, strengthening of intensity of a brain blood-groove can be followed by regulatory reaction of arteries — their konstriktion, and at sharp increase in the general ABP she is very considerable. If the functional condition of unstriated muscles of arteries at the same time is changed in such a way that process of reduction is strengthened, and process of relaxation, on the contrary, is lowered, then in response to increase in the general ABP there comes vasoconstriction patol, type, i.e. vasomotor spasm (see). These phenomena are most expressed at short-term increase in the general ABP. At disturbances of a blood-brain barrier, at tendency to wet brain build-up of pressure in capillaries causes sharp strengthening of filtering of water from blood in tissue of a brain where she is late therefore hypostasis of a brain develops. Increase in intensity of a brain blood-groove is especially dangerous at action of the accessory factors (a craniocereberal injury, a heavy hypoxia) promoting edematization.
Compensatory mechanisms — the obligatory component of a symptom complex, to-ry characterizes each disturbance of M. to. At the same time compensation is carried out by the same regulatory mechanisms, to-rye function also in normal conditions, but they are more strained.
At increase or decrease in the general ABP compensation is carried out by means of change of resistance in vascular system of a brain, and the major role is played by large brain arteries (internal carotid and vertebral arteries). If they do not provide compensation, then microcirculation stops being adequate and arteries of a soft meninx are involved in regulation. At bystry increase in the general ABP the specified mechanisms of compensation can work not at once, and then intensity of a brain blood-groove sharply amplifies with all possible effects. In nek-ry cases compensatory mechanisms can work very absolutely and even at hron, hypertensia when the general is sharply raised by the ABP (280 — 300 mm of mercury.) considerable time; intensity of a brain blood-groove remains normal and nevrol, disturbances do not arise.
At decrease in the general ABP compensatory mechanisms can also maintain normal intensity of a brain blood-groove, and depending on degree of perfection of their work limits of compensation can be not identical at different persons. At perfect compensation normal intensity of a brain blood-groove is noted at decrease in the general ABP even to 30 mm of mercury., whereas not lower than 55 — 60 mm of mercury consider by usually lower bound of an autoregulyation of a brain blood-groove the ABP.
At increase in resistance in these or those arteries of a brain (at an embolism, thrombosis, a vasomotor spasm) compensation is carried out due to collateral inflow of blood. Compensation is provided in this case by the following factors:
1. Existence of arterial vessels on which collateral inflow of blood can be carried out. The arterial system of a brain contains a large number of collateral ways in the form of a wide anastomosis of an arterial circle, and also numerous interarterial macro - and a microanastomosis in system of arteries of a soft meninx. However a structure of arterial system individually, anomalies of development, especially in the field of an arterial (villiziyev) circle are frequent. The small arteries located in the thickness of tissue of a brain have no anastomosis of arterial type and though a capillary network in all brain continuous, it cannot provide collateral inflow of blood to the neighboring sites of fabric if inflow of blood to them from arteries is broken.
2. Increase in pressure difference in collateral arterial ways at emergence of obstacles for a blood-groove in this or that brain artery (a hemodynamic factor).
3. Active expansion of collateral arteries and small arterial branches to the periphery from the place of closing of a gleam of an artery. This vazodilatation represents, apparently, manifestation of regulation of adequate blood supply of tissue of brain: as soon as there is a deficit of inflow of blood to fabric, the physiological mechanism causing dilatation begins to work) those arterial branches, to-rye are bringing for this microcirculator system. Thereof resistance for a blood-groove in collateral ways decreases that promotes inflow of blood to area with the lowered blood supply.
Efficiency of collateral inflow of blood to area of the lowered blood supply at different persons is not identical. The mechanisms providing collateral inflow of blood depending on specific conditions can be broken (as well as other mechanisms of regulation and compensation). So, ability of collateral arteries to expansion at sclerous processes in their walls falls that interferes with collateral inflow of blood to area of the broken blood supply.
Duality is characteristic of mechanisms of compensation, i.e. compensation of one disturbances causes other circulator frustration. E.g., at recovery in the tissue of a brain which had deficiency of blood supply, a blood-groove in it emergence of a post-ischemic hyperemia is possible, at a cut intensity of microcirculation can be much higher than the level necessary for ensuring metabolic processes in fabric, i.e. there occurs the excess perfusion of blood promoting, in particular, development of post-ischemic hypostasis of a brain.
On adequate and pharmakol, influences the perverted reactivity of arteries of a brain can be observed. So, normal vazodilatatorny reaction of the healthy vessels surrounding the center of ischemia of tissue of brain, and absence that at the affected arteries in the center of ischemia therefore blood is redistributed from the center of ischemia in healthy vessels is the cornerstone of a syndrome of «intracerebral burglarizing», and ischemia is aggravated.
PATHOLOGICAL ANATOMY of FRUSTRATION of CEREBRAL CIRCULATION
Morfol. signs of disturbance of M. to. come to light in the form of focal and diffusion changes, weight and localization to-rykh are various and substantially depend on a basic disease and direct mechanisms of development of a circulatory disturbance. Distinguish three main forms of disturbance
of M. to.: hemorrhages (hemorrhagic stroke), heart attacks of a brain (ischemic stroke) and multiple melkoochagovy changes of substance of various character of a brain (vascular encephalopathy).
Stroke (see) — sharply arisen M.'s frustration to., followed by focal injuries of a brain and resistant nevrol, symptoms. The hemorrhagic stroke is caused by a hematencephalon from patholologically the changed vessels usually against the background of arterial hypertension or hemorrhage in substance of a brain or under its covers as a result of a rupture of inborn arterial or arteriovenous aneurisms (see. Aneurism of vessels of a brain ). Hematencephalons can arise also at an injury of a skull or ruptures of vessels a tumor of a brain.
At insufficient inflow of blood to sites of a brain there is focal ischemia (see) with the subsequent development of a heart attack of a brain.
At vascular encephalopathies (see) the multiple small centers of quite often various character and different prescription come to light: sites of loss of neurocytes, small hemorrhages, the small fresh and organized centers of a full and incomplete necrosis, gliomezodermalny hems and cysts of the small sizes. A part of these changes can be revealed only at microscopic examination. Often their development is shown clinically in the form of vascular and brain crises or passing disturbances of M. to. Usually such circulatory disturbances are observed at a hypertension and secondary arterial hypertension. In the period of crisis permeability of walls of small vessels sharply increases that involves edematization of a brain, plasmorrhagias (see) with formation of the centers of a perivascular entsefalolizis, and also small perivascular hemorrhages. At the organization of these hemorrhages there is a glial reaction, there are macrophages absorbing decomposition products of blood and fabric, hemosiderin is formed; as a result the small gliomezodermalny hem or a cyst containing pigments of blood forms. Developing of multiple diapedetic hemorrhages with similar dynamics is possible also at other diseases and states connected with disturbance of permeability of vascular walls (hemorrhagic diathesis, diseases of blood, uraemia, nek-ry infections, intoxications and avitaminosis). At repeated crises the gleam of small arteries and arterioles is narrowed as a result of treatment by plasma of walls of vessels; additional narrowing up to full closing of a gleam is caused by proliferation of an internal cover. It is the reason of a hypoxia and emergence of melkoochagovy necroses (microheart attacks). It is possible to observe the centers at different stages of development: the centers with neurocytes in a phase of ischemia, the organized centers with granular spheres and corpulent astrocytes, the organized centers in the form of gliomezodermalny hems and cysts, free of pigments of blood. Small cysts (lacunas) arising after heart attacks (is more rare after hemorrhages), can be multiple; they are often symmetrized in subcrustal nodes, white matter of hemispheres, a thalamus and the varoliyevy bridge. This peculiar form of vascular pathology carries the name of a lacunary state (status lacunaris).
Atherosclerosis of vessels of a brain can be the cause of development of polymorphic melkoochagovy changes of substance of a brain: from focal ganglioznokletochny loss before development of the centers of a full and incomplete necrosis. Their localization corresponds to the pool of the changed vessel. More often they arise on the mechanism of sosudistomozgovy insufficiency. However perhaps full closing of a gleam of a vessel owing to an obliteration or thrombosis, is more rare than a microembolism. M.'s disturbances to. meet more often at elderly persons therefore along with atherosclerosis (see) age changes of vessels are found: a diffusion sclerosis of vascular walls, the proliferation of an internal cover leading to a bigger narrowing of a gleam.
the Reason of M.'s disturbances to. there can be following diseases: atherosclerosis, hypertension, combination of atherosclerosis to arterial hypertension, vasculites, napr, rheumatic, syphilitic, heart disease, diseases of blood, etc. On the nature of disturbances of M. to. allocate initial manifestations of insufficiency of blood supply of a brain, acute disorders of M. to. (passing disturbances, different types of a stroke, acute hypertensive encephalopathy, etc.), hron, M.'s insufficiency to. The nature of pathology of vessels is various (obstruction, narrowing of a gleam, excesses and aneurisms of vessels etc.). Localization of defeats of M. to. it is diverse (a hemisphere, a brainstem, a cerebellum, etc.). Along with arteries (a carotid, main artery, etc.) also brain veins and sine therefore, except disturbances of arterial circulation, in a brain the cerebrovascular frustration caused by damage of brain veins and sine can be observed are surprised. The main nevrol, the symptoms caused by vascular defeat of a nervous system, the following: motive disturbances (paresis, paralyzes, Extrapyramidal disorders, disorders of coordination, hyperkinesias); disorders of sensitivity (decrease in sensitivity, sometimes pains); focal disturbances of the highest cortical functions (aphasia, agraphia, alexia, etc.); epileptiform attacks (the general, focal); changes of intelligence, memory, emotional and strong-willed sphere; psychopathological symptomatology.
Clinical manifestations of insufficiency of cerebral circulation
Initial manifestations of insufficiency of brain blood supply represent the compensated stage latentno of the proceeding vascular pathology of a brain. Compensation of deficit of blood supply of a brain at the same time is defective since it is at a critical level and mechanisms of self-control of a brain blood-groove not always work adequately that is shown at increase in need of a brain for inflow of blood (e.g., at exercise and intellectual stress) and brings to a number of subjective signs defined a wedge, to manifestations, expressed; the headache, dizziness, noise in the head, a memory impairment, decrease in intellectual working capacity are most characteristic.
Acute disorders of cerebral circulation are characterized by emergence a wedge, symptoms from a nervous system against the background of the existing vascular disease: atherosclerosis, idiopathic hypertensia or arterial hypertension of other origin, rheumatism and nek-ry other diseases. The disease is characterized by usually sudden beginning and differs in considerable dynamics of all-brain and local symptoms of damage of a brain. During the definition of character of an acute disorder of M. to. consider the further course of a disease, rate of development nevrol, symptoms, their features and degree of manifestation.
Allocate passing disturbances of M. to. — cerebral vascular crises (see), characterized by regress nevrol, signs no more than within a day after their emergence, and acute disorders with more resistant, sometimes irreversible nevrol, symptomatology — strokes (see), to-rye subdivide on hemorrhagic and ischemic (a heart attack of a brain).
Passing disturbances — the most widespread type of an acute disorder of M. to.; are more often observed at atherosclerosis with defeat of brain vessels and at an idiopathic hypertensia. Wedge, their manifestations, as well as pathogenetic mechanisms, polimorfna. At atherosclerosis in a wedge, a picture passing focal symptoms from vertebral and basilar or carotid system prevail, at an idiopathic hypertensia — all-brain symptoms and symptoms of dysfunction of century of N of page.
In a brain carry venous hemorrhages, vein thromboses to acute disorders of venous blood circulation and sine (see. Thrombosis, thrombosis of vessels of a brain ), thrombophlebitises (see. Thrombophlebitis ). Venous hemorrhages can arise at a hemorrhagic stroke as the manifestation accompanying it or to be an independent form that meets seldom.
Chronic disturbances of cerebral circulation lead to gradually progressing organic change of tissue of brain — the distsirkulyatorny encephalopathy caused by various vascular diseases (a hypertension, atherosclerosis, rheumatism, etc.). The Distsirkulyatorny encephalopathy arising at various diseases has much in common as in a wedge, manifestations, and during. However its nek-ry features depend from etiol, a factor. The pseudo-neurotic syndrome, emotional instability, a memory impairment, a headache, dizziness, frustration of a dream, a sonitus and other symptoms is characteristic of an initial stage of distsirkulyatorny encephalopathy. Often take place the increased vascular reactivity, instability of the ABP, especially at an idiopathic hypertensia, for a cut passing increases in the ABP are characteristic in this stage. Signs of organic lesion of a nervous system at the same time usually do not come to light. On an eyeground narrowing of arteries of a retina is noted. Efficiency of the patient remains, to lay down. - prof. of an action can promote permanent compensation.
At the adverse course of a disease the wedge, manifestations become heavier and persistent. There are not rough symptoms of organic lesion: asymmetry of a cranial innervation, tendon jerks, muscle tone, indistinct pyramidal signs, etc. Vegetovascular lability is noted, quite often there are cerebral vascular crises, later to-rykh the organic symptomatology amplifies. Often the mentality changes: there is an uncertainty in itself, tendency to hypochiondrial states, phobias, an explosibility, an egocentrism, faintheartedness; dysmnesias, especially on current events go deep. Changes on an eyeground become more considerable and have character of an atherosclerotic or hypertensive angiosclerosis. Working ability of patients decreases.
At sharply expressed distsirkulyatorny encephalopathy in connection with increase morfol, changes of tissue of brain the wedge, a picture becomes heavier. Decrease in memory and attention progresses, the focus of interest is narrowed, and dementia gradually develops. Repeated vascular cerebral crises and strokes aggravate a disease. In nevrol, the status at the same time clear symptoms of organic lesion are noted: insufficiency of a cranial innervation, nystagmus (see), signs of pyramidal insufficiency, sometimes speech frustration (see. Speech ), paresis of extremities (see. Paralyses, paresis ), disturbances sensitivity (see) and pelvic frustration. The pseudobulbar syndrome is often observed (see. Pseudobulbar paralysis ). At defeat of subcrustal nodes there are various Extrapyramidal symptoms, to-rye can reach degree parkinsonism (see). On eyeground (see) the rough changes characteristic of late stages of atherosclerosis or an idiopathic hypertensia are observed.
To hron, to disturbances of venous blood circulation refer venous stagnation and venous encephalopathy. Venous stagnation is caused cordial and a pulmonary heart, a prelum of extracranial veins in a neck, an injury of a skull and brain and other reasons. Thanks to rich compensatory opportunities of system M. to. signs of difficulty of venous outflow even at its long existence can be absent. At the phenomena of a decompensation the wedge, a picture consists of headaches, convulsive attacks, cerebellar symptoms, disturbance of functions of cranial nerves.
Venous encephalopathy is characterized by a variety a wedge, manifestations. Allocate the following syndromes: gipertenzionny (pseudo-tumorous), the syndrome of scattered melkoochagovy damage of a brain, an asthenic syndrome, for to-rykh are characteristic signs of venous stagnation and dominance of all-brain symptoms over focal. Also carry a bettolepsy (tussive epilepsy) to venous encephalopathy, edges develops at the diseases causing venous stagnation in a brain. Persistent cough comes to an end with attacks of epileptiform character, at the same time there can come the sudden loss of consciousness.
Disturbances of cerebral circulation in certain vascular pools. A wedge, syndromes at ischemic disturbances of M. to. passing character and heart attacks of a brain are result of the factors depending on a condition of the main vessels and vessels of the brain and on compensatory opportunities of collateral circulation. On the basis a wedge, a syndrome it is possible to judge degree of a distsirkulyation or size of a heart attack of a brain, its localization and a confinedness to the pool of this or that vessel of a brain. However not always on one wedge, the picture manages to solve, this syndrome is caused by pathology of the main or brain vessel whether it is connected with full or partial occlusion of a vessel. Reliable information about it can be obtained only by means of an angiography. The wedge, syndromes arising at a hematencephalon not always correspond to the pool of the become torn vessel since the streamed blood can spread to the areas supplied by other vessels.
The wedge, a picture at extensive heart attacks in the pool of a front brain artery is characterized by spastic paralysis of extremities — proximal department of a hand and distal department of a leg; sometimes a delay or an incontience of urine, existence of a grasp reflex and symptoms of oral automatism (see Reflexes pathological). At the bilateral centers the mentality is often broken (an aspontannost, decrease in criticism, easing of memory, etc.). Quite often the apraxia of the left hand (at the left-side centers) which is a consequence of defeat of a corpus collosum takes place (see. Apraxia ). Unsharply expressed disorders of sensitivity on the paralyzed leg are sometimes observed. At defeat of the pool of a paracentral artery Stotta's monoparesis usually takes place, at damage of a calloused artery there is left-side apraxia.
At defeat of all pool of an average brain artery the syndrome of a total heart attack of a brain — contralateral is observed hemiplegia (see), a hemianaesthesia (see. Sensitivity ) and hemianopsia (see); at heart attacks in the left hemisphere — aphasia of the mixed type or total, at heart attacks in the right hemisphere — an anosognosia — a peculiar disturbance of perception of disorders of sensitivity and movements of a body (see Agnosia). The heart attack in the pool of the general trunk of the ascending branches of an average brain artery is followed by a hemiplegia or a hemiparesis with preferential defeat of function of a hand, gemigipesteziy cortical type, at the left-side centers — motor aphasia. The heart attack in the pool of back branches of an average brain artery is shown by the so-called parietal and temporal and angular syndrome including hemianopsias) (half or nizhnekvadrantny) and a hemianaesthesia with an astereognosis (disorder of recognition of objects at palpation); in connection with disturbance of sensitivity, especially deep, so-called afferent paresis of extremities can take place. At the left-side centers touch and anamnestic aphasia, apraxia, an acalculia and agraphia joins these symptoms (see. Aphasia ) and manual agnosia. At the right-hand centers frustration of a body scheme can take place. At a heart attack in the pool of deep branches of an average brain artery the spastic hemiplegia is observed, it is changeable — disturbance of sensitivity, at the centers in the left hemisphere — motor aphasia. Heart attacks in the pool of separate branches of an average brain artery proceed with more limited symptomatology: at a heart attack in the pool of a pretsentralny frontal branch paralysis preferential of the bottom of the person, language and chewing muscles is observed; at the left-side centers at the same time there is motor aphasia. At the bilateral centers in this area the pseudobulbar syndrome with disturbance of an articulation, swallowing and an aphonia develops. At a heart attack in the pool of a parietofrontal branch of an average brain artery (a rolandovy artery) the hemiplegia or a hemiparesis with dominance of paresis in a hand is observed.
At damage of a front artery of a vascular texture wedge. the syndrome includes a hemiplegia, a hemianaesthesia, sometimes a hemianopsia, vasculomotor disturbances in the paralyzed extremities. Aphasia at the same time is absent.
At a heart attack in the pool of cortical branches of a back brain artery it is observed we babble-naya a hemianopsia, usually with safety of macular sight, or a verkhnekvadrantny hemianopsia; there are phenomena less often metamorphopsias (see) and visual agnosia. At defeats in the left hemisphere the alexia and unsharply expressed touch and anamnestic aphasia can be observed, dysmnesias, especially short-term are frequent. At a heart attack in the pool of a talamokolenchaty artery there is a thalamic syndrome of Dezherin — Russia (see. Thalamus ), including a gemigipesteziya or a hemianaesthesia, and also a hyperpathia and a dizesteziya on the party opposite to defeat, thalamic pains in a half of a body opposite to defeat, passing contralateral hemiparesis; the hemianopsia, hyperkinesias of athetotic and horeoatetozny character are changeably observed (see. Hyperkinesias ), a hemiataxia (see. Ataxy ), trophic and vegetative frustration. The heart attack in the pool of a talamoperforiruyushchy artery is characterized by existence of a heavy ataxy and intentsionny tremor in contralateral extremities (an upper red nucleus syndrome). Sometimes instead of a tremor in a hand there is a hyperkinesia of horeoatetozny type or a hemiballism. A peculiar tonic installation of a hand — «thalamic arm» can be also observed.
A wedge, manifestations at damage of arteries of a brain trunk differ in polymorphism. Heart attacks in the field of a brain trunk are result of damage of arteries of vertebral and basilar system at various levels. Spottiness — dispersion of several, usually small centers of a heart attack is characteristic of ischemic defeats of a brain trunk.
At a heart attack in the pool of paramedian arteries of a mesencephalon the so-called lower red nucleus syndrome — paralysis is most often observed third cranial nerve (see) on the party of the center, an ataxy and trembling of intentsionny character in contralateral extremities; the choreiform hyperkinesia is sometimes observed. At defeat of oral departments of a red kernel the third cranial nerve can not suffer; in such cases there is an upper red nucleus syndrome (an ataxy and an intentsionny tremor in contralateral extremities). At the heart attack taking the basis of legs of a brain Weber's syndrome develops (see. Alternating syndromes ). Damage to a back longitudinal bunch is caused by paralysis or paresis of a look (see. Look paralysis, spasm ), what is sometimes combined with a nystagmus. At a heart attack in the pool of short lateral arteries of a mesencephalon (back branches of a vascular texture) there is paresis of extremities of the party opposite to defeat with a gemigipesteziya. Damage of a brain in the pool of long lateral arteries of a mesencephalon at a distsirkulyation in an upper cerebellar artery is followed by choreiform and atetoidny hyperkinesias on the party of the center, disturbance painful and a thermoesthesia on the party opposite to defeat, sometimes a myoclonia of a soft palate. At a heart attack in the pool of a chetverokholmny artery symptoms of defeat of a third cranial nerve, and also paresis and paralyzes of a look are observed. Paralysis of a look up and paresis of convergence (Parino's syndrome, or a syndrome of a back commissure) is especially characteristic. Often cerebellar symptoms take place. At extensive, especially bilateral, the heart attacks in the field of a mesencephalon affecting kernels of a reticular formation disturbances of consciousness and a dream often take place, pedunkulyarny hallucinosis is sometimes observed.
The heart attack in the pool of paramedian arteries of the bridge causes or the upper medial syndrome of the bridge, to-ry is characterized by a contralateral hemiplegia with disorder of deep sensitivity, or the lower medial syndrome, at Krom along with a contralateral hemiplegia and disorder of deep sensitivity paresis taking away, and sometimes a facial nerve on the party of the center is noted. The bilateral heart attack leads to a tetraplegia, pseudobulbar and cerebellar symptoms.
At a heart attack in the pool of short lateral branches there is a lateral syndrome of the bridge. The gomolateralny cerebellar syndrome which is combined with disturbance of superficial sensitivity, and sometimes and pyramidal signs on the party opposite to defeat is most constantly observed; on the party of the center Horner's syndrome can be noted (see. Bernard — Horner a syndrome ). At the centers in an average and lower third of a side part of the bridge there is a frustration painful and a thermoesthesia of the person on the party of the center and frustration of these types of sensitivity on a half of a trunk opposite to defeat and extremities, i.e. the alternating gemigipesteziya or a hemianaesthesia can appear. At the centers in the lower third of a side part of the bridge along with the main syndrome the flaccid paralysis of mimic muscles on the party of the center can take place,
the Heart attack of oral departments of a tire of the bridge in a zone of blood supply of an upper cerebellar artery is followed by frustration painful and a thermoesthesia on the party opposite to defeat, cerebellar disturbances on Goma to the lateral party, paresis of a look of bridge type (the patient looks at the paralyzed extremities), sometimes a nystagmus. The hyperkinesia of choreiform or atetoidny character and Horner's syndrome on the party of defeat, sometimes a myoclonic syndrome can join it.
The heart attack in a caudal part of a tire of the bridge, blood supply to-rogo is carried out by an anteroinferior cerebellar artery and the short bending-around arteries, is followed by not rough gomolateralny cerebellar symptoms, the dissociated disorder of sensitivity on a half of a body opposite to defeat, sometimes a flaccid paralysis of facial muscles on the party of defeat.
At bilateral heart attacks in the field of a tire of the bridge the pseudobulbar syndrome clearly is expressed.
At a distsirkulyation in arteries of a myelencephalon, napr, at the medial heart attack arising in the pool of paramedian arteries defeat of a hypoglossal nerve on the party of defeat and paralysis of extremities of the opposite side is noted. Sometimes only the pyramidal way with one or from two parties is surprised depending on what one is observed - or bilateral spastic paralysis. The lateral heart attack of a myelencephalon arising at a distsirkulyation in a vertebral artery or in a back lower cerebellar artery is clinically shown by Wallenberg's syndrome — Zakharchenko (see. Alternating syndromes ).
Wedge, manifestations of okklyuziruyushchy defeat of ekstrakranialny department of an internal carotid artery in an initial stage proceed more often in the form of passing disturbances of M. to. Nevrol, symptomatology is various. Approximately in 1/3 cases the alternating optiko-pyramidal syndrome — a blindness or decrease in sight, sometimes with an atrophy of an optic nerve on side of the affected artery (owing to a distsirkulyation in an orbital artery), and pyramidal disturbances on the party opposite to defeat takes place. Sometimes these symptoms arise at the same time, is sometimes dissociated. The most frequent at occlusion of an internal carotid artery are signs of a distsirkulyation in the pool of an average brain artery: paresis of extremities of the party opposite to defeat, usually cortical type with more expressed defect of a hand. At heart attacks in the pool of the left internal carotid artery aphasia, usually motor often develops. Disturbances of sensitivity and a hemianopsia can meet. Epileptiform attacks are occasionally noted.
At the heart attacks caused by the intracranial thrombosis of an internal carotid artery proceeding with dissociation of an arterial circle along with a hemiplegia and a gemigipesteziya sharply expressed all-brain symptoms are observed: headache, vomiting, disturbance of consciousness, psychomotor excitement; there is a secondary stem syndrome.
The syndrome of okklyuziruyushchy defeat of an internal carotid artery, in addition to intermittent) courses of a disease and specified nevrol, manifestations, is characterized by easing or disappearance of a pulsation of the struck carotid artery, is frequent existence of vascular noise over it and decrease in retinal pressure on the same party. The prelum of not struck carotid artery causes dizziness, sometimes a faint, spasms in healthy extremities.
«Spottiness» of defeat of various departments of the pool of pozvonochnobazilyarny system is characteristic of okklyuziruyushchy defeat of ekstrakranialny department of a vertebral artery: often vestibular disturbances (dizziness, a nystagmus), frustration of a statics and coordination of movements, visual and oculomotor disturbances, a dysarthtia take place; less often motive and sensitive disturbances are defined. At nek-ry patients attacks of sudden falling in connection with loss of a postural tone, an adynamia, a hypersomnia are noted. Dysmnesias on current events of type are quite often observed korsakovsky syndrome (see).
At obstruction of intracranial department of a vertebral artery resistant alternating syndromes of damage of a medulla are combined with passing symptoms of ischemia of oral departments of a brain trunk, occipital and temporal shares. Approximately Wallenberg's syndromes — Zakharchenko, Babinsky — Nazhotta and other syndromes of hemilesion of lower parts of a brain trunk develop in 75% of cases. At bilateral thrombosis of a vertebral artery there is a heavy dysphagia, phonations, breath and cordial activity is broken.
Acute obstruction of a basilar artery is followed by symptoms of preferential defeat of the bridge with disorder of consciousness up to a coma, bystry development of damages of cranial nerves (III, IV, V, VI, VII couples), a pseudobulbar syndrome, paralyzes of extremities with existence bilateral patol. reflexes. Vegetative and visceral crises, hyperthermia, disorder of vital functions are observed.
Diagnosis of disturbances of cerebral circulation
the Basis for the diagnosis of initial manifestation of inferiority of M. to. is: existence of two or more subjective signs which are often repeating; absence at a usual nevrol, survey of symptoms of organic lesion of c. N of page and detection of signs of the general vascular disease (atherosclerosis, an idiopathic hypertensia, a vasculitis, vascular dystonia, etc.) that is especially important since subjective complaints of the patient are not Pathognomonic for initial manifestations of vascular inferiority of a brain and can be marked out also at other states (a neurasthenia, asthenic syndromes of various genesis). For establishment at a sick general vascular disease carrying out versatile a wedge, inspections is necessary.
The basis for the diagnosis of an acute disorder of M. to. sudden emergence of symptoms of organic lesion of a brain against the background of the general vascular disease with considerable dynamics of all-brain and local symptoms serves. At disappearance of these symptoms in time less than 24 hours passing disturbance of M. is diagnosed to., in the presence of more resistant symptomatology — a brain stroke. During the definition of nature of a stroke not separate signs, but their set have the leading value. Pathognomonic signs for this or that type of a stroke do not exist. For diagnosis of a hemorrhagic stroke ABP and cerebral hypertensive crises in the anamnesis, the sudden beginning of a disease, the bystry progressing aggravation of symptoms, considerable expressiveness not only focal, but also all-brain symptoms, clear vegetative disturbances, early emergence of the symptoms caused by the shift and a prelum of a brain trunk, quickly occurring changes from blood (a leukocytosis, a neutrocytosis with shift to the left in a leukocytic formula, increase in an index of Krebs to 6 and above), availability of blood in cerebrospinal liquid matter high.
Development of a stroke in a dream or against the background of weakening of cardiovascular activity, absence of arterial hypertension, existence of a cardiosclerosis, a myocardial infarction in the anamnesis, relative stability of vital functions, safety of consciousness testifies to a heart attack of a brain at a massive nevrol, symptomatology, absence or weak expressiveness of a secondary trunk syndrome, rather slow development of a disease, lack of changes from blood in the first days after a stroke.
Data help with diagnosis ekhoentsefalografiya (see) — the shift of the M-echo towards a contralateral hemisphere speaks well for intratserebralny hemorrhage rather. Rentgenol, a research of vessels of a brain after administration of contrast mediums (see. Vertebralnaya angiography , Carotid angiography ) at vnutripolusharny hematomas reveals an avascular zone and shift of arterial trunks; at a heart attack of a brain okklyuziruyushchy process in the main or intracerebral vessels often comes to light, dislocation of arterial trunks is uncharacteristic. Valuable information at diagnosis of a stroke is given by a computer tomography of the head (see. Tomography computer ).
Philosophy of therapy of disturbance of cerebral circulation
At initial manifestations of inferiority of M. to. therapy shall be directed to treatment of the basic vascular disease, normalization of a work-rest schedule, to use of the means improving metabolism of tissue of brain and a hemodynamics.
At acute disorders of M. to. urgent actions since it is not always clear whether there will be M.'s disturbance to are required. passing or resistant therefore absolute mental and physical rest is anyway necessary. It is necessary to stop a brain vascular attack at the earliest stages of its development. Treatment of passing disturbances of M. to. (vascular cerebral crises) shall provide first of all normalization of the ABP, cordial activity and a brain hemodynamics with inclusion in need of anti-hypoxemic, antiedematous and various symptomatic means, including sedative, in nek-ry cases anticoagulants and antiagregant apply. Treatment at a hematencephalon is directed to a stop of bleeding and the prevention of its resuming, to fight against wet brain and disturbance of vital functions. At treatment of a heart attack
of a brain hold the events directed to improvement of blood supply of a brain: normalization of cordial activity and the ABP, increase in inflow of blood to a brain by expansion of regional brain vessels, reduction of a vasospasm and improvement of microcirculation, and also normalization physical. - chemical properties of blood, in particular on restoring the balance in coagulant system of blood for the prevention of thromboembolisms and for dissolution of already formed blood clots.
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