Understanding strokes, avoiding becoming a statisticPublished 10:22am Tuesday, May 22, 2012
You’ve had a stroke. Not exactly the words you’d like to hear. Most of us don’t know much about strokes. We just know that we don’t want to have one, and people who do usually have some form of a physical deficit or handicap after the event occurs. I’ll do my best to keep the explanations that follow in basic terms, since like you, I’m not a doctor, but it’s important to know about strokes.
Strokes fall into two broad categories: ischemic and hemorrhagic. The vast majority of strokes are ischemic strokes. Ischemic strokes are caused when a blood clot forms in an artery that supplies the brain with blood. Typically the clot arises at a site already narrowed by the buildup of plaque – fatty deposits that accumulate in the walls of arteries. That’s why your cholesterol numbers matter.
Another type of ischemic stroke is caused by an embolism. It occurs when a blood clot or fragment of plaque – an embolus – forms elsewhere in the body and travels through the bloodstream until it lodges in a smaller artery carrying blood to the brain. If blood to the brain is stopped and not restored quickly, nerve cells in the affected area of the brain will die. The death of those cells is what causes permanent physical or mental damage.
Hemorrhagic strokes are the result of ruptures or tears in vessels that supply blood to the brain, allowing blood to leak into surrounding tissues. These are usually caused by high blood pressure or when a weakened segment of a small artery to the brain balloons out – called an aneurysm – fills with blood and ruptures. The extent and severity of damage depends on the amount of blood that leaks from the affected artery.