Causes
Two Kinds of Stroke
There are two kinds of stroke: ischemic and hemorrhagic. Ischemic stroke occurs when an artery to the brain is blocked. Hemorrhagic stroke occurs when a blood vessel in the brain bursts causing bleeding into or around the brain.
Ischemic Stroke
Blood Flow to Your Brain is Blocked
An ischemic stroke occurs when blood flow to your brain is blocked. Most strokes are of this type. They happen when the arteries to your brain are blocked or narrowed, reducing blood flow. When this happens, your brain is deprived of needed oxygen and nutrients and brain cells die within a few minutes. There are two main forms of ischemic stroke.
Thrombotic Stroke
A thrombotic stroke occurs when a blood clot forms in an artery that supplies the brain with blood. This happens in arteries that are clogged by fatty deposits called plaques. This often involves the carotid arteries in your neck.
Embolic Stroke
An embolic stroke occurs when a blood clot forms in a blood vessel away from your brain and is carried through your bloodstream to lodge in smaller brain arteries. This often occurs as a result of an arrhythmia in the heart's upper chambers, known as the atria. The abnormal rhythm can cause impaired blood flow and formation of a clot.
Hemorrhagic stroke
Weakened Blood Vessel in the Brain Ruptures
This type of stroke takes place when a weakened blood vessel in the brain ruptures. It causes sudden bleeding in or around the brain, and the force of the collecting blood escaping from the vessel can cause excessive pressure in the brain, damaging surrounding brain tissue.