A stroke occurs when blood flow to the brain is stopped and the brain is starved of blood and oxygen. There are two types of strokes: ischemic strokes (where the blood flow is blocked) and hemorrhagic strokes (brain bleeds), which are also called cerebral hemorrhages. Hemorrhagic strokes are more deadly than ischemic strokes, but ischemic strokes are more common (87 percent of strokes).
Ischemic Stroke Caused by Blood Clot
The presence of artherosclerosis (fatty deposits and plaque in the arteries) can affect blood flow and cause the formation of a blood clot in the brain; this is called a thrombotic stroke.
Ischemic Stroke Caused by Embolism
Blood clots or other particles that form in one place and travel to the brain are called emboli and can cause a cerebral embolism, which can lead to a stroke; the most common cause of this type of emboli is atrial fibrillation.
Hemorrhagic Stroke Caused by Weakened Artery Walls
A common cause of cerebral hemorrhage is high blood pressure because this condition weakens the blood vessel walls; sometimes a weak area in the blood vessel wall balloons outward (aneurysm) and eventually bursts, causing bleeding.
Other Causes of Hemorrhagic Stroke
Bleeding in the brain can be caused by an abnormal connection between an artery and a vein (arterial-venous malformation) that leaks. Cancer metastases to the brain, some illegal drugs and bleeding disorders can cause brain hemorrhages as well.
The goal in treating an ischemic stroke is to remove the clot often using thrombolytic (clot-busting) medications, while the goal of treatment in hemorrhagic stroke is to stop the bleeding and to stop the swelling of the tissue impacted by the bleeding.