A stroke is a cerebral vascular accident that interrupts the normal flow of blood through (or to) the brain. It is caused by a blood clot or a break in the wall of a blood vessel that deprives the brain of oxygen. Strokes are generally caused by arteriosclerosis, blood clotting disorders, heart attacks, or heavy drinking. Although strokes are generally caused by external factors, there are some that occur spontaneously without apparent causes.
The most common symptom of a stroke is a sudden loss of coordination or weakness on one side of the body. This is usually accompanied by headaches, dizziness, and/or vision problems. About ten percent of strokes are completely silent and are only detected by a CT scan or MRI. Other symptoms may include slurred speech, inability to move one side of the body, or partial paralysis. In most cases, strokes are also the result of underlying medical conditions (e.g., heart disease or high blood pressure). In some instances, however, strokes may occur without any predisposing medical conditions.
What are the Different Types of Stroke?
There are four major types of stroke: ischemic, hemorrhagic, mixed, and embolic. Ischemic strokes result from a blockage or narrowing of a blood vessel. This blockage deprives the brain of oxygen, which leads to cell damage and death. Hemorrhagic strokes are caused by bleeding into the brain tissue from a ruptured blood vessel. Mixed strokes are caused by a combination of both an ischemic and a hemorrhagic event. Embolic strokes are caused by a foreign body (e.g., a clot, fat, or fibrin) that has lodged in a blood vessel and then traveled to the brain.
Each type of stroke has a specific risk factor. For example, diabetes and heart disease are common contributors to ischemic strokes. Age, genetics, and heredity are also contributing factors to ischemic strokes. An embolic stroke may be caused by excessive drinking or cocaine use. Hemorrhagic strokes often occur in people who have had multiple bouts of heavy drinking. The risk factors for a hemorrhagic stroke include hypertension, coronary heart disease, and cerebral atherosclerosis.
Can Strokes Be Prevented?
It is very important to recognize the risk factors for stroke. This way, people can take measures to minimize their chances of having a stroke. These measures include controlling high blood pressure, avoiding tobacco and excessive alcohol use, and monitoring one’s blood cholesterol levels. Diet and exercise may also be used to prevent strokes. If at least five risk factors for stroke exist in a person, that person is considered to be at high risk of having a stroke. People with high blood pressure, diabetes, and/or heart disease should consult their doctors about taking prescribed medications to lower their blood cholesterol or blood glucose levels.
In some instances, a stroke may be prevented by surgically removing a blood clot, or thrombus, that has formed in a blood vessel. This is called a clot evacuation procedure and was first performed in the 1970s. Clot evacuations are generally performed after the onset of ischemic stroke symptoms. However, in some cases, a clot evacuation may be performed in asymptomatic individuals with high blood clotting tendencies. The first step of a clot evacuation is to locate the blockage in a blood vessel, usually by performing a computerized tomography (CT) scan or magnetic resonance imaging (MRI). Once the location of the clot has been determined, a catheter is inserted into the vessel and maneuvered to the site. Once there, the clot is evacuated.
Another way to prevent strokes is by taking medications that act on the blood vessels. For example, aspirin and clopidogrel (Plavix) may be used to thin the blood and prevent blood clots from forming. These medications may be taken daily, or just before a surgical procedure or high risk event. In some instances, a combination of medications and/or foods may be required to achieve the desired effect. In rare instances, people with high blood clotting tendencies may require blood thinners every day of their life. In some cases, a stent may be placed in the affected blood vessel to keep it open and allow for better tissue oxygenation. This is generally done in conjunction with coronary artery bypass graft (CABG) surgery. Finally, counseling and/or stress management may be used to prevent strokes in people who have stress-related conditions (e.g., hypertension, hyperlipidemia, or diabetes). People with these conditions should speak to their doctors about how they can best manage their psychological and/or physiological state to prevent strokes.
Overall, it is important to remember that not all strokes are created equal. Some are more serious than others, depending on their size and location within the brain. It is also important to recognize the risk factors for different types of stroke so that people can take measures to minimize their chances of having a stroke.