Stroke: Symptoms and Risk Factors
Stroke, or cerebrovascular accident (CVA), is the third leading cause of death in the United States, resulting in more than 150,000 deaths per year.
About 80 percent of strokes are caused by a decrease in blood flow to the brain (called ischemic strokes). This is usually the result of a blood clot that has formed within an artery to the brain or has formed elsewhere (e.g., the heart) and traveled to a brain artery, where it has become lodged. Loss of blood flow can also occur if the heart malfunctions and no longer pumps blood effectively. Strokes can also be caused by a break in a blood vessel, causing blood to flow into the brain, compressing and damaging brain tissue. These are referred to as hemorrhagic strokes.
The most common causes of stroke are hypertension and atherosclerosis. In both cases, these result in damage to the arteries that feed the brain with blood and oxygen.
Symptoms of a stroke can be mild or severe and may include:
- Numbness or weakness of the face, arm, or leg, usually on one side of the body
- Difficulty speaking or understanding
- Visual disturbances, which may include partial or complete blindness
- Severe headache with no known cause
A transient ischemic attack (TIA) is a "mini-stroke." The symptoms are similar to those of a stroke, but a TIA usually lasts only 30 to 60 minutes. Although TIAs are not as serious as strokes, they can be a warning sign of an oncoming stroke.
- Race: African-Americans and Latinos have a higher risk of stroke. However, it is unclear whether this increased risk is due to genetic factors.
- Age: The risk of stroke increases with age, especially after age 55.
- Gender: Women have a slightly higher risk than men.
- Smoking: Cigarette smoking increases the risk for stroke significantly.
- Underlying medical diseases: People with hypertension, diabetes, elevated cholesterol, atrial fibrillation, and narrowing (stenosis) of the carotid arteries that lead to the brain have a significantly increased risk of stroke. These disorders should be prevented or treated appropriately.
- Drug and alcohol abuse, especially cocaine abuse.
- Poor nutrition: High-fat, high-sodium diets and a lack of key nutrients, such as folic acid, have been associated with an increased risk for stroke (see Nutritional Considerations).
- Sedentary lifestyle: People who rarely engage in physical activity have an increased risk of stroke.
- If a stroke is suspected, immediate medical attention and hospitalization are necessary.
- The evaluation begins with a detailed history and physical examination. Several medical tests are required to determine if a stroke has occurred and to check for possible causes. These tests may include blood tests, electrocardiogram (EKG), and CT or MRI scans of the head.
- In people who are at risk for a stroke, or who have had a transient ischemic attack, an evaluation is needed to determine the risk of future stroke. This may include an echocardiogram of the heart, a Doppler scan of the carotid arteries in the neck, or magnetic resonance angiogram (MRA) of the carotid arteries.
- Immediate management of a stroke includes supplemental oxygen, intravenous fluids, aspirin, and antihypertensive medications.
- In some cases, thrombolytic agents, or "clot-busting" drugs, are used to dissolve artery-blocking clots in the brain. These drugs can only be used within a few hours of the onset of the stroke, and only in certain patients. Patients at risk of bleeding are not eligible.
- Surgery may be needed in some instances, as in the case of a cerebral bleeding, a ruptured aneurysm, or narrowing of the carotid arteries.
- Most cases of stroke are preventible. Lifestyle changes that can significantly reduce the risk of stroke include smoking cessation, weight loss, blood pressure and cholesterol reduction, and control of blood sugar. In many cases, a healthy diet and regular exercise can normalize body weight, cholesterol, blood pressure, and blood sugar.
- In some cases, medications may be necessary. The most common are drugs to control blood pressure and cholesterol and medications that â€œthinâ€ the blood, such as aspirin, coumadin, and clopidogrel.
- Patients with atherosclerosis of the carotid arteries in the neck may require a surgical procedure, carotid endarterectomy, to reestablish blood flow. This procedure is relatively simple and can significantly reduce the risk of a future stroke.
Stroke: Nutritional Considerations
The following steps are key to preventing a stroke:
- Reducing dietary fat and cholesterol. Individuals with higher blood cholesterol concentrations tend to have a higher risk of stroke. Studies show that men and women who have high dietary intake of saturated fat and cholesterol-which raise blood cholesterol concentrations-have an increased risk of stroke.
The main food sources that contain saturated fats are animal products (meat, dairy products, eggs) and tropical oils (palm oil, coconut oil). Cholesterol, which is not the same as fat, is found only in animal-derived products (meat, dairy products, and eggs). A low-fat, vegan diet leads to the most dramatic reductions in saturated fat.
- Eating a balanced diet with plenty of fruits, vegetables, and whole grains. Eating more fruits and vegetables is associated with a reduced risk for stroke. These healthy foods can displace high-fat, high-cholesterol animal products. Fruits and vegetables also provide important nutrients, including carotenoids, vitamin C, vitamin E, and folate, all of which have been associated with reduced stroke risk in epidemiologic studies.
Fruits, vegetables, and whole grains also provide fiber, which is associated with lower risk for stroke and other diseases.
- Consuming less sodium and more potassium. It is well known that sodium (that is, salt) in foods increases the risk of hypertension, which increases the risk of stroke. Studies have shown that lowering dietary sodium intake will decrease the risk of having a stroke, as well as the risk of dying from a stroke. Foods that tend to have high levels of sodium include processed and packaged foods, some canned foods, "fast foods," baked goods, salty or smoked meats and fishes, and many breakfast cereals.
In contrast, potassium is beneficial. Increasing dietary intake of potassium lowers the risk of having a stroke and dying from a stroke. Fruits and vegetables are the best sources of potassium.
- Maintaining a healthy body weight. Maintaining a healthy body weight reduces the risk of stroke. For weight-control tips, meal plans, and recipes, consult How to Maintain a Healthy Weight.
- Limiting alcohol consumption to no more than one to two alcoholic drinks daily
- A nutritionist can offer more advice about making healthy food choices.