Stroke is a form of cerebrovascular disease, meaning it affects the vessels that supply blood to the brain. Stroke was first called “apoplexy,” a Greek word that means “to strike down.” Symptoms may appear slowly or suddenly, but the underlying conditions that lead to the disease are usually present for years before a stroke happens.

The American Heart Association estimates that about 795,000 Americans have a new or recurrent stroke each year. In people who survive a stroke, there may be paralysis, emotional problems, or trouble with speech, memory, or judgment. How bad the injury or impairment is depends on what artery was blocked and for how long.

Most strokes happen in people 65 years and older. Although many strokes happen without warning, there are physical symptoms that may signal you are having a stroke. Learn to recognize the signs.

What is a stroke?

A stroke is an injury to the brain that may also severely affect the body. A stroke happens when blood supply to part of the brain is cut off or when there is bleeding into or around the brain.

Your brain is a large, soft mass of tissue made up of billions of nerve cells. It is your body’s main control center and helps you to see, hear, taste, smell, talk, and walk. It is also the control center for thought, emotion, memory, judgment, and awareness.

The brain’s nerve cells need a constant supply of oxygen and sugar (glucose), which are carried by the blood. When blood fails to get through to parts of the brain, the oxygen supply to those areas is cut off. This is called ischemia. Without oxygen, brain cells die. The longer the brain is without blood, the more severe the damage will be. The area of tissue death that results from ischemia is known as an infarction.

Blood flow to the brain can be blocked in two ways:

• A clump of blood called a blood clot blocks an artery in the brain or neck.
• A weakened artery bursts in the brain.

Your brain cells control movement, so part of your body may become paralyzed after a stroke. If the right side of your brain is affected, the left side of your body may become paralyzed. If the left side of your brain is affected, the right side of your body may become paralyzed.

The effects of a stroke may be mild or severe, short-term or permanent. Some people have this cerebrovascular disease and recover completely within a few days, while others may never recover. The severity depends on

• What part of your brain is affected
• How much brain cell damage there is
• How quickly your body can restore blood to the injured parts of your brain
• How quickly the healthy parts of your brain can take over for the injured area

What are the causes?

A blood clot or a blocked artery leading to the brain causes about 87% of all strokes. This type of cerebrovascular disease is called an ischemic stroke. There are 2 kinds of ischemic stroke: cerebral thrombosis and cerebral embolism.

The other 13% of strokes are caused by ruptured or leaky blood vessels in or around the brain. This type of injury is called a hemorrhagic stroke. There are 2 kinds of hemorrhagic strokes: cerebral and subarachnoid. Hemorrhagic strokes cause more deaths than ischemic strokes, but those who survive a hemorrhagic stroke recover more fully and have fewer long-lasting disabilities.

How is the disease diagnosed?

Tests that show images of the brain (CT scan, MRI), measure the brain’s electrical activity (EEG), and show blood flow to the brain (carotid duplex scan) are used to find out the type and severity of cerebrovascular disease.

What are the treatments for stroke?

Advanced treatments and rehabilitation are helping many stroke patients return to their homes and families. Stroke treatments include anti-clotting drugs, hospital care, rehabilitation, and, rarely, surgery.

The best therapy for stroke is prevention. By knowing the warning symptoms and controlling risk factors such as cigarette or tobacco smoking, high blood pressure, diabetes, and heart disease, you can reduce your risk.

How can you lower your risk of stroke?

You can do a lot to lower your risk of this injury. Here are the top ten steps recommended by the National Stroke Association:

1. Know your blood pressure and have it checked at least every year. If it is high, work with your doctor to lower it.
2. Find out if you have a type of heart rhythm disorder called atrial fibrillation.
3. If you smoke, stop.
4. If you drink alcohol, do so in moderation.
5. Find out if you have high cholesterol then work with your doctor to get it under control.
6. If you have diabetes, follow your doctor’s advice carefully to control it.
7. Include exercise in the activities you enjoy every day.
8. Enjoy a low-sodium (salt), low-fat diet.
9. Ask your doctor if you have circulation problems that may increase your risk.
10. If you have any stroke symptoms or observe them in others, call 9-1-1 right away.

 Facts

• Stroke is the No. 5 cause of death in the United States, killing more than 129,000 people a year.
• Someone in the U.S. has a stroke about once every 40 seconds.
• Stroke is the leading preventable cause of disability.
• African-Americans have nearly twice the risk for a first-ever stroke than white people, and a much higher death rate from the disease.