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Brain ischemia has been linked to a variety of diseases or abnormalities. Individuals with sickle cell anemia, compressed blood vessels, ventricular tachycardia, plaque buildup in the arteries, blood clots, extremely low blood pressure as a result of heart attack, and congenital heart defects have a higher predisposition to brain ischemia in comparison to the average population.
The thrombosis of the veins themselves causes venous infarction (damage to brain tissue due to a congested and therefore insufficient blood supply). This results in cerebral edema (both vasogenic and cytotoxic edema), and leads to small petechial haemorrhages that may merge into large haematomas.
Brain ischemia is insufficient blood flow to the brain, and can be acute or chronic. Acute ischemic stroke is a neurological emergency typically caused by a blood clot blocking blood flow in a vessel in the brain. [15] Chronic ischemia of the brain may result in a form of dementia called vascular dementia. [16]
A stroke is the rapid decline of brain function due to a disturbance in the supply of blood to the brain. [13] This can be due to ischemia, thrombus, embolus (a lodged particle) or hemorrhage (a bleed). [13] In thrombotic stroke, a thrombus (blood clot) usually forms around atherosclerotic plaques. Since blockage of the artery is gradual, the ...
Atrial fibrillation causes blood clots to form within the heart, which may travel to the arteries within the brain and cause an embolism. The embolism prevents blood flow to the brain, which leads to a stroke. [26] An aneurysm is an abnormal bulging of small sections of arteries, which increases the risk of artery rupture.
The disruption to blood supply can come from many causes, including: Thrombosis (obstruction of a blood vessel by a blood clot forming locally) Embolism (obstruction due to an embolus from elsewhere in the body), [18] Systemic hypoperfusion (general decrease in blood supply, e.g., in shock) [19] Cerebral venous sinus thrombosis. [20]
A thrombus (pl. thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cross-linked fibrin protein. The substance making up a thrombus is sometimes called cruor.
An inflammatory response is mounted, and phagocytic cells engulf damaged but still viable tissue. Harmful chemicals damage the blood–brain barrier. Cerebral edema (swelling of the brain) occurs due to leakage of large molecules like albumins from blood vessels through the damaged blood brain barrier.