Brain Basics: Preventing Stroke

Introduction

If you're like most Americans, you plan your future. When you take a job, you examine its benefit plan. When you buy a home, you consider its location and condition so that your investment is safe. Today, more and more Americans are protecting their most important asset—their brain. Are you?

What is a Stroke?

A stroke, or "brain attack," occurs when blood circulation to the brain fails. Brain cells can die from decreased blood flow and the resulting lack of oxygen. There are two broad categories of stroke: those caused by a blockage of blood flow and those caused by bleeding into the brain. A blockage of a blood vessel in the brain or neck, called an ischemic stroke, is the most frequent cause of stroke and is responsible for about 80 percent of strokes. These blockages stem from three conditions: the formation of a clot within a blood vessel of the brain or neck, called thrombosis; the movement of a clot from another part of the body such as the heart to the brain, called embolism; or a severe narrowing of an artery in or leading to the brain, called stenosis. Bleeding into the brain or the spaces surrounding the brain causes the second type of stroke, called hemorrhagic stroke.

Two key steps you can take will lower your risk of death or disability from stroke: control stroke's risk factors and know stroke's warning signs. Scientific research conducted by the NINDS has identified warning signs and a large number of risk factors.

What are Warning Signs of a Stroke?

Warning signs are clues your body sends that your brain is not receiving enough oxygen. If you observe one or more of these signs of a stroke or "brain attack," don't wait, call a doctor or 911 right away!

Sudden numbness or weakness of face, arm, or leg, especially on one side of the body
Sudden confusion, or trouble talking or understanding speech
Sudden trouble seeing in one or both eyes
Sudden trouble walking, dizziness, or loss of balance or coordination
Sudden severe headache with no known cause

Other danger signs that may occur include double vision, drowsiness, and nausea or vomiting. Sometimes the warning signs may last only a few moments and then disappear. These brief episodes, known as transient ischemic attacks or TIAs, are sometimes called "mini-strokes." Although brief, they identify an underlying serious condition that isn't going away without medical help. Unfortunately, since they clear up, many people ignore them. Don't. Paying attention to them can save your life.

What Are the Treatable Risk Factors?

High blood pressure, or hypertension.

Hypertension is by far the most potent risk factor for stroke. Hypertension causes a two-to four-fold increase in the risk of stroke before age 80. If your blood pressure is high, you and your doctor need to work out an individual strategy to bring it down to the normal range. Some ways that work: Maintain proper weight. Avoid drugs known to raise blood pressure. Eat right: cut down on salt and eat fruits and vegetables to increase potassium in your diet. Exercise more. Your doctor may prescribe medicines that help lower blood pressure. Controlling blood pressure will also help you avoid heart disease, diabetes, and kidney failure.

Cigarette smoking.

Cigarette smoking causes about a two-fold increase in the risk of ischemic stroke and up to a four-fold increase in the risk of hemorrhagic stroke. It has been linked to the buildup of fatty substances (atherosclerosis) in the carotid artery, the main neck artery supplying blood to the brain. Blockage of this artery is the leading cause of stroke in Americans. Also, nicotine raises blood pressure; carbon monoxide from smoking reduces the amount of oxygen your blood can carry to the brain; and cigarette smoke makes your blood thicker and more likely to clot. Smoking also promotes aneurysm formation. Your doctor can recommend programs and medications that may help you quit smoking. By quitting, at any age, you also reduce your risk of lung disease, heart disease, and a number of cancers including lung cancer.

Heart disease.

Common heart disorders such as coronary artery disease, valve defects, irregular heart beat (atrial fibrillation), and enlargement of one of the heart's chambers can result in blood clots that may break loose and block vessels in or leading to the brain. Atrial fibrillation—which is more prevalent in older people—is responsible for one in four strokes after age 80, and is associated with higher mortality and disability. The most common blood vessel disease is atherosclerosis. Hypertension promotes atherosclerosis and causes mechanical damage to the walls of blood vessels. Your doctor will treat your heart disease and may also prescribe medication, such as aspirin, to help prevent the formation of clots. Your doctor may recommend surgery to clean out a clogged neck artery if you match a particular risk profile. If you are over 50, NINDS scientists believe you and your doctor should make a decision about aspirin therapy. A doctor can evaluate your risk factors and help you decide if you will benefit from aspirin or other blood-thinning therapy.

Warning signs or history of TIA or stroke.

If you experience a TIA, get help at once. If you’ve previously had a TIA or stroke, your risk of having a stroke is many times greater than someone who has never had one. Many communities encourage those with stroke's warning signs to dial 911 for emergency medical assistance. If you have had a stroke in the past, it's important to reduce your risk of a second stroke. Your brain helps you recover from a stroke by asking the unaffected brain regions to do double duty. That means a second stroke can be twice as bad.

Diabetes.

In terms of stroke and cardiovascular disease, having diabetes is the equivalent of aging 15 years. You may think this disorder affects only the body's ability to use sugar, or glucose. But it also causes destructive changes in the blood vessels throughout the body, including the brain. Also, if blood glucose levels are high at the time of a stroke, then brain damage is usually more severe and extensive than when blood glucose is well-controlled. Hypertension is common among diabetics and accounts for much of their increased stroke risk. Treating diabetes can delay the onset of complications that increase the risk of stroke.

Cholesterol imbalance.

Low-density lipoprotein cholesterol (LDL) carries cholesterol (a fatty substance) through the blood and delivers it to cells. Excess LDL can cause cholesterol to build up in blood vessels, leading to atherosclerosis. Atherosclerosis is the major cause of blood vessel narrowing, leading to both heart attack and stroke.