Transient ischemic attack
A transient ischemic attack (TIA) or “mini stroke” is just like a stroke, except a TIA lasts for a very short time — usually less than five minutes — and leaves no permanent damage. A TIA may predict that a stroke will occur sometime in the future and should never be ignored. Call 9-1-1 immediately if you suspect a TIA is occurring.
An ischemic stroke occurs when the blood flow in an artery of the brain is blocked and brain tissue dies. Ischemic strokes account for nearly 85 percent of all strokes.
There are two kinds of ischemic strokes: embolic and thrombotic.
- Embolic stroke: Occurs when a blood clot or fragment of plaque (fatty deposit) forms in the body and travels through the bloodstream to the brain. Once in the brain, the clot blocks a blood vessel, causing a stroke.
- Thrombotic stroke: Occurs when there is a buildup of plaque and blood clots in the lining of the blood vessel wall, which narrows the blood vessel. This can interrupt the blood flow and causes a stroke.
A hemorrhagic stroke occurs when a weakened blood vessel breaks and bleeding occurs inside the brain.
There are two types of hemorrhagic stroke:
- Intracerebral hemorrhage (ICH): Caused when a burst blood vessel bleeds into the brain; the bleeding causes brain cells to die, resulting in that part of the brain not functioning properly. ICH is typically due to chronic risk factors that damage the vessels over time, such as high blood pressure, smoking, diabetes, heavy alcohol use and high cholesterol.
- Subarachnoid hemorrhage (SAH): A blood vessel bursts near the surface of the brain causing blood to pour into the area around the outside of the brain. The bleeding can increase pressure in the brain and lead to injured brain cells. This type of stroke has many possible causes, but typically is the result of an aneurysm (a bulging, weakened vessel wall) that ruptures.