Stress Management

Stroke

Types and Causes of Stroke

There are two major forms of stroke

Ischemic Stroke - Blockage of a blood vessel supplying the brain

Hemorrhagic Stroke - Bleeding into or around the brain.

Ischemic Stroke

Ischemic strokes are virtually identical to heart attacks, except that they happen in your brain instead of your heart. These strokes begin with tiny injuries to brain arteries caused by high blood pressure, smoking, or a high-fat, high- cholesterol diet. Over time, these injured areas get covered with cholesterol-rich deposits called plaques that narrow the injured arteries.

Sometimes a plaque ruptures, causing a blood clot in the artery and cutting off the blood supply to part of your brain. That's an ischemic stroke. In fact, heart attacks and ischemic strokes are so similar that the American Heart Association now calls them brain attacks.

About 80 percent of all strokes are ischemic.

The process of clotting is necessary to stop bleeding and to allow repair of damaged areas of arteries or veins. However, when blood clots develop in the wrong place within an artery they can cause devastating injury by interfering with the normal flow of blood. Problems with clotting become more frequent as people age.

Blood clots can cause ischemia and infarction in two ways.

1. Embolic stroke

Here, a clot forms in a part of the body other than the brain. It then travels through blood vessels and becomes wedged in a brain artery. This free-roaming clot (called an embolus) is often formed in the heart. A stroke caused by an embolus is called an embolic stroke.

2. Thrombotic Stroke

A blood clot forms in one of the cerebral arteries. It stays attached to the artery wall until it grows large enough to block blood flow. The resulting stroke is called a thrombotic stroke.

Ischemic Strokes From Stenosis

Stenosis is a narrowing of the artery due to the buildup of plaque and blood clots along the artery wall. Stenosis can occur in large arteries leading to large vessel disease and small arteries leading to small vessel disease. When a stroke occurs due to small vessel disease, a very small infarction results, sometimes called a lacunar infarction.

The most common blood vessel disease that causes stenosis is atherosclerosis. In atherosclerosis, deposits of plaque build up along the inner walls of large and medium-sized arteries, causing thickening, hardening, and loss of elasticity of artery walls and decreased blood flow.

Source: National Institutes of Health

Caution: If you suspect a stroke, seek emergency medical treatment immediately. Time is of essence.

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