Types of Strokes
Roughly 88% of all strokes are ischemic. An ischemic stroke can be either large or small (see above images). During an ischemic stroke the blood flow to the brain is blocked. This blockage prevents oxygen and nutrients from reaching brain cells. Within a few minutes, these cells begin to die.
- One cause of an ischemic stroke can be atherosclerosis, a condition in which a fatty substance called plaque causes arteries in the brain and neck to become clogged and narrow. The plaque can restrict blood flow through the artery or cause a blood clot to block the flow completely.
- The second cause of an ischemic stroke is an embolic clot. An embolic clot occurs when a blood clot or other small piece of material breaks loose from an artery wall or from the inside lining of the heart. These embolic clots can lodge in an artery in the brain. Irregular heart rhythms, known as atrial fibrillation, can cause embolic clots and increase the risk of stroke. Embolic strokes can be a complication of blood pooling in the upper chambers of the heart (atria) in people who have abnormal heart rhythms (arrhythmias) such as atrial fibrillation. The risk of stroke from atrial fibrillation can be reduced by taking “blood thinners” such as anticoagulants or antiplatelts. Please see your doctor to find out the best course of action, never self medicate.
It is estimated that 12% of all strokes are hemorrhagic. There are two types of hemorrhagic stroke: intracerebral hemorrhage and subarachnoid hemorrhage.
During a intracerebral hemorrhage a blood vessel within the brain leaks or ruptures causing bleeding. When this happens, blood leaking into brain tissue from the hemorrhage damages brain cells. High blood pressure is a common cause of an intracerebral hemorrhage.
During a subarachnoid hemorrhage, blood leaks under the lining of the brain. Subarachnoid hemorrhages are often caused by a small bubble on an artery known as a cerebral aneurysm. Of the two forms of stroke, a hemorrhagic stroke poses the more immediate danger. However, ischemic stroke has a number of risk factors that can be controlled.