There are two types of “brain attacks” ischemic and hemorrhagic. With ischemic strokes, a blood clot blocks or “plugs” a blood vessel in the brain. With hemorrhagic strokes, a blood vessel in the brain breaks or ruptures.

Ischemic Stroke
Ischemic strokes are the most common kind of stroke causing 84 percent of all strokes. Please note, the most important treatment and prevention strategies refer to ischemic rather then hemorrhagic stroke.

In everyday life, blood clotting is beneficial. When you are bleeding from a wound, blood clots work to slow and eventually stop the bleeding.  In the case of stroke, however, blood clots are dangerous because they can block arteries and cut off blood flow to the brain, a process called ischemia. An ischemic stroke can occur in two ways—embolic and thrombotic strokes.

Embolic Stroke
In an embolic stroke, a blood clot forms somewhere in the body (usually the heart) and travels through the bloodstream to the brain.  Once in your brain, the clot eventually travels to a blood vessel small enough to block its passage. The clot lodges there, blocking the blood vessels and causing a stroke. The medical word for this type of blood clot is embolus.

Thrombotic
In the second type of ischemic stroke, blood flow is impaired because of a blockage to one or more of the arteries supplying blood to the brain.  The process is leading to this blockage is known as thrombotisis. Strokes caused in this way are called thrombotic strokes. That’s because the medical word for a clot that forms on a blood-vessel deposit is thrombus.

Blood-clot strokes can also happen as the result of unhealthy blood vessels clogged with a buildup of fatty deposits and cholesterol. Your body regards these build-ups as multiple, tiny and repeated injuries to the blood vessel wall. So your body reacts to these injuries just as it would if you were bleeding from a wound—it responds by forming clots.