What Is an Ischemic Stroke?

What Is an Ischemic Stroke?

An Ischemic (‘is-skeem-ic) stroke is the death of an area of brain tissue (cerebral infarction) when the artery to the brain is blocked. The brain is dependent on its arteries to bring fresh blood from the heart and lungs.

The blood carries oxygen and nutrients to the brain, and takes away carbon dioxide and cellular waste. An ischemic stroke is most often the result of blockage of an artery, most commonly a branch of one of the internal carotid arteries.

Blockages are most commonly blood clots (thrombi) or pieces of fatty deposits, (plaques) due to atherosclerosis. Another common cause of ischemic strokes is a lacunar infarction: a small artery deep in the brain becomes blocked by a combination of fat and connective tissue-not a blood clot. Lipohyalinosis and usually occurs in older people with diabetes and poorly controlled high blood pressure.

Lipohyalinosis is different from atherosclerosis, even though both may cause blockage of arteries, only a small part of the brain is damaged in lacunar infarction. An ischemic stroke can also result from any disorder that reduces the amount of oxygen or blood supplied to the brain, such as severe blood loss or very low blood pressure.

On rare occasions a stroke occurs when the blood flow to the brain is normal, but does not contain enough oxygen. This can occur in anemia, suffocation, and carbon monoxide poisoning. Usually these disorders cause widespread damage and a coma results. Symptoms occur suddenly and may include weakness, muscle paralysis, loss of feeling on one side of the body, incoherent or nonexistent speech, vision problems, dizziness of loss of co?�rdination and balance. Ischemic stroke is by far the most common kind of stroke.

About 85-88% of all strokes are ischemic. Strokes can affect people of all ages, including children. Many people are older (60 years and above). The risk of stroke increases with age and are more common in women than men. Also African-Americans more commonly have strokes than white Americans. Many people who suffer a stroke have other co-existing conditions which put them at higher risk. Some of these conditions are: high blood pressure (hypertension), heart disease, smoking or diabetes. This is not an all-inclusive list. There is no way to totally prevent a stroke, but controlling blood pressure, cholesterol and weight are helpful.

Ischemic strokes are the most common type of stroke. All strokes are medical emergencies. Blood supplies are blocked and medical treatment is needed for a good outcome.