Cerebrovascular atherosclerotic thrombosis
Among the many causes of thrombosis of cerebral vessels listed in the table below, the majority of cases occur in their atherosclerotic thrombosis. Atherosclerosis affects extracranial and intracerebral arteries of specific localization. Atheromatous plaques were more likely to occur in the ground and bending branches of large vessels, and thrombosis usually occurs where this plaque narrows the artery more often.
Details of the process that accompanies the development of thrombosis, not clear. Atheromatous lesion itself is located between the intima and tunica media of the artery. It penetrates and destroys the medial shell of the vessel. Plaque is composed of hyaline connective tissue, fibroblasts, macrophages and smooth muscle cells. As the plaque deposits are interspersed with foci of cholesterol crystals.
It is assumed that thrombosis starts to develop when the atherosclerotic process leads to fragmentation of the endothelial lining of the vascular layer, thus creating a hotbed of platelet accumulation and thrombus formation near the wall.
Sometimes it flows through the blood vessel lumen dissecting the atheromatous plaque, it stratifies. Such penetration may be the mechanism of formation of crater cavities and become a hotbed of the formation of thrombus. Less commonly, to a further narrowing of the lumen causes bleeding in the plaque.
Atheromatous narrowing of the vessel in its configuration resembles an hourglass with the length of the narrow segment of 1-2 mm. Intravascular thrombosis can develop in the area of this segment with narrowing of the lumen, and before or after it. Blockage of blood clots (thrombotic occlusion ) usually occurs when atherosclerotic plaque narrows the lumen of the vessel so that prevents further flow of blood through it.
It is difficult to predict what will cause brain damage atherosclerotic thrombosis. The clinical picture may affect collateral blood flow available, the rate of thrombus occlusion of the lumen of the vessel (thrombotic occlusion), occurrence of thrombosis, embolism after further along the vessel.
The clinical picture of obstruction in some arteries supplying the brain varies in different patients, with most syndromes is partial in nature. Given descriptions characterize myocardial ischemia and in pools of blood supply artery thrombosis separate, but similar clinic is also observed after embolization. Sometimes the bleeding within a particular vascular bed can give a close symptoms.
Causes of cerebrovascular atherosclerotic thrombosis
|Thrombophlebitis of cerebral vessels||- secondary thrombosis of cerebral vessels in infectious processes in the ear, paranasal sinuses, facial, etc.;
- thrombosis of cerebral vessels with meningitis and subdural empyema;
- thrombosis of cerebral vessels in conditions of exhaustion, postpartum, postoperative heart failure;
- cerebral thrombosis in hematologic diseases (polycythemia, sickle cell anemia) and in unexplained reasons.
|Arteritis of cerebral vessels||A. syphilis, secondary arteritis in purulent and tuberculous meningitis, rare diseases (typhoid, schistosomiasis, malaria (?), Trichinosis (?) Mukoroz, etc.);
B. Disorders of connective tissue: polyarteritis (necrotizing, granulomatous, allergic, Wegener), temporal arteritis, Takayasu's disease, granulomatous arteritis of the aorta, systemic lupus erythematosus.
|Hematological disorders||- polycythemia;
- sickle cell anemia;
- thrombotic thrombocytopenic purpura.
|Injury of the carotid artery|
|Dissecting of aortic aneurysm|
|Systemic hypotension||- "Simple syncope";
- acute blood loss;
- myocardial infarction;
- Adams' disease;
- traumatic and surgical shock;
- a sensitive carotid sinus;
- severe postural hypotension.
|Complications of arteriography (angiography with contrast)|
|Migraine aura with persistent deficits|
|The syndrome of cerebral herniation (stem, hemispheres or cerebellum):
- into the cerebellar mantling foramen (central downward or upward cerebellar herniation),
- into the foramen magnum (transforaminal herniation cerebellar tonsils),
- herniation under the dural falciform process (herniation of cingulate gyrus).
|Various causes of thrombosis of cerebral vessels||- radioactive or X-ray irradiation;
- lateral compression of the intracerebral hematoma;
- infarction (stroke) in the basin of the middle cerebral artery with unknown mechanism of development with a closed head injury (concussion or brain contusion);
- unruptured saccular aneurysm compression;
- intravascular thrombus in the fusiform aneurysm;
- local delamination carotid or middle cerebral artery;
- complication of oral contraceptives.
|Unexplained causes of thrombosis of cerebral vessels||for example, in childhood|