Stroke

Introduction

What should I know about Stroke?

The term “stroke" or “paralytic stroke" is commonly used to describe a sudden problem with the brain that is usually related to its blood supply. A “stroke," therefore, can be due to ischemia (decreased blood supply), infarction (interrupted blood supply), or hemorrhage (severe bleeding), and usually means that there is some kind of permanent problem with the nervous system. (1) All three of these causes (ischemia, infarction, or hemorrhage) would be due to cerebrovascular disease (disease related to the blood supply to the brain).

Cerebrovascular disease can be described as any disease affecting the blood vessels, blood flow, or quality of the blood in the brain. (2) Other terms for this disease include apoplexy or cerebrovascular accident (CVA). In the United States, the term stroke is most often used. Most strokes are caused by ischemia and infarction because of diseases of the large, small, and medium-sized arteries in the brain. Cerebral embolism (blood clot in the brain) causes strokes about 20 percent of the time. Hemorrhage into the brain tissue account for about 15 percent of all strokes.

Cerebrovascular disease is divided into two broad categories: thrombotic and embolic. Thrombotic strokes occur without warning symptoms in 80-90 percent of patients. They often occur with symptoms that start and stop, and then worsen over several minutes or hours. Embolic strokes have symptoms that are at their maximum when the stroke occurs. (3)

Within 10 seconds after brain blood flow stops, the brain tissue begins to fail. The electrical activity of the brain slows down, and brain function begins to be affected. If the circulation is restored immediately, brain function recovers. If the problem continues for a few minutes, injury to the nerve cells result. When the blood flow returns, the brain’s recovery may not be complete. (4) When the blood flow is interrupted for longer periods of time, the brain tissue will die.

Atherosclerosis (hardening) of the brain arteries occurs in the same way that atherosclerosis occurs anywhere else in the body. The atherosclerosis that occurs in the arteries of the brain might be affected slightly less than the aorta, arteries in the heart, and arteries of the limbs. The atherosclerosis that develops includes the formation of plaque, and the narrowing or blockage of arteries. Plaque formation also stimulates the formation of clots, increasing the risk of stroke.

The other broad category of cerebrovascular ischemia is a brain embolism. Approximately 20 percent of strokes are caused by emboli. While any region of the brain may be affected by embolism, the middle cerebral artery is usually involved. The most common types of embolism result from pieces or fragments of an arterial blood clot that have broken off. The embolus usually circulates until it is too large to move through the blood vessel. The blockage often occurs in a narrowed area, and both sides of the brain are affected the same way. Hemorrhage often occurs in this process, due to blood returning into ischemic tissues. The size of the embolus may vary from large to so small that it cannot be noticed.

The third most frequent cause, accounting for approximately 15 percent of strokes, is hemorrhage in the brain. Some causes of hemorrhage include increased blood pressure and rupture of an artery. This allows for movement of blood into the brain tissue, which forms a mass. As bleeding continues, the mass enlarges, pushing aside other tissue. As tissue is pushed and moved, brain function may be affected.

While many risk factors have been identified that increases a person’s risk for stroke, hypertension (high blood pressure), is by far, the greatest. Hypertension has been identified as a factor in 70 percent of all strokes. A famous heart study, the Framingham study, reported that there is a direct link between increased blood pressure and stroke risk. (5)

A problem with heart function is the next most important single treatable risk factor for stroke. Individuals with heart diseases such as coronary heart disease, congestive heart failure, enlargement of the left ventricle, and arrhythmias (specifically atrial fibrillation) have more than twice the stroke risk compared to those with normal heart function. (6) Atrial fibrillation patients have a sixfold increase in stroke frequency over those without fibrillation. (7) , (8) , (9)

Transient ischemic attacks (TIA's) are episodes of focused ischemic problems lasting less than 24 hours. (10) The most common time these last is from a few seconds up to five to 10 minutes, depending on where in the brain the event occurs. Symptoms depend on the part of the brain that has been affected by the decrease or absence of blood flow. Often, TIA's occur as a result of emboli, which break away from distant blood clots. These emboli are then dissolved by the body’s natural system, allowing normal blood flow and brain function to return. The more often a TIA occurs, the higher the probability of a stroke, and a previous stroke is a greater risk factor for additional strokes. (11)

Other groups considered at higher risk for stroke include those with sickle cell disease, and middle-aged male patients with a history of stroke on their mother’s side of the family. Patients with increased blood thickness are also considered at higher risk for stroke.

Hyperlipidemia and hypercholesterolemia (increased cholesterol and fats in the blood) are risk factors for the development of atherosclerosis, which increases the risks of both coronary heart disease and stroke. Another major risk factor for both ischemic and hemorrhagic stroke is cigarette smoking. Smokers have two to three times the risk of stroke compared with non-smokers, and a fourfold to sixfold increase in stroke risk compared with those who have never smoked. (12)

Statistic

World Health Organization, 2002.

  • Annually, 15 million people worldwide suffer a stroke.
  • Of these, 5 million die and another 5 million are left permanently disabled, placing a burden on family and community.
  • Stroke is uncommon in people under 40 years; when it does occur, the main cause is high blood pressure.
  • Stroke also occurs in about 8% of children with sickle cell disease.

American Heart Association Statistical Update, 2005.

    Each year 700,000 people experience a stroke. On average, someone in the United States has a stroke every 45 seconds, and every 3 minutes, someone dies from a stroke. 40,000 more women than men experience strokes. Strokes accounted for more than 1 in 15 deaths in the US in 2002. From 1992 to 2002, the rate of deaths actually dropped, but the number of strokes increased.
  • African Americans have about twice the risk of a first stroke incident than Caucasians.

Not available

Signs and Symptoms

[span class=alert]The following list does not insure the presence of this health condition. Please see the text and your healthcare professional for more information.[/span]

A stroke is likely occurring if there is a sudden onset of one or more of the following symptoms:

  • Numbness or weakness in the face, arms, or legs (usually only on one side of the body)
  • Confusion, difficulty understanding speech, or trouble speaking
  • Severe headache that has no known cause
  • Blurry, double, or decreased vision in one or both eyes
  • Loss of balance, loss of coordination, trouble walking, or dizziness

If any of these signs or symptoms are present, please consult a healthcare professional immediately.

Treatment Options

Conventional

Treatments for cerebrovascular disease are generally divided into categories of prevention and managing severe symptoms. Many risk factors for stroke have been identified. Family history of stroke, diabetes mellitus, hypertension, tobacco smoking, and increased cholesterol increase the risk of stroke. Of these factors, hypertension is the most important. Generally, all hypertension should be treated. The first line of treatment should be through changes in lifestyle and diet.

Clinical studies have shown the benefits of aspirin in men in preventing a TIA as well as in producing a decrease in major blood vessel problems. Drugs used are as follows:

    Aspirin for stroke prevention. The use of coated aspirin may be easier on the stomach for some individuals. Ticlopidine or clopidogrel are currently recommended alternatives to aspirin in cases where the patient cannot take aspirin, or if aspirin fails to stop or decrease the TIA. Warfarin is recommended for some patients. Dosing must be done very carefully, and patients must be monitored closely for bleeding problems. Alteplase is recommended as emergency therapy in acute ischemic stroke if therapy can be started within three hours of the event.

Surgery is done when the goal is to remove the blockage and increase blood flow to the ischemic area in the brain.

Nutritional Suplementation


Vitamin B6, Vitamin B12

Increased amounts of a byproduct called homocysteine in the blood are now recognized as risk factors for stroke and other forms of heart disease. (13) Three B-vitamins, folic acid, vitamin B6, and vitamin B12, are required for the breakdown of homocysteine. Without enough of these B-vitamins, homocysteine can increase in the blood and raise the risk for stroke as well as other brain circulation and heart problems. (14) , (15)


Docosahexaenoic Acid (DHA)

Studies are showing the beneficial effects of fish oils on the cardiovascular disease. (16) Animal studies report that using DHA for five weeks resulted in a decrease in blood thickness and clotting factors. (17) Dietary fish oils are becoming known for their ability to protect against heart disease. A study that examined the effects of docosahexaenoic acid reported it to be effective at decreasing stroke-related risk factors such as hypertension and narrowing of blood vessels. (18) These results show that docosahexaenoic acid may be the active ingredient in fish oils which may provide some protection to the heart. A study in humans was conducted in Japan. The levels of docosahexaenoic acid (DHA) were higher in individuals who lived in fishing villages where deaths from strokes were low compared to people who lived in farming villages where the occurrence and death rate from strokes was much higher. (19)


Potassium

Results from the Nurses Health Study reported that potassium in the diet was linked to a decreased occurrence of ischemic stroke in women, (20) and potassium has also been identified to affect stroke risk in men. (21) , (22) In an eight-year study, men with the highest amount of potassium in their diet were 38 percent less likely to have a stroke compared to men with the lowest amount of potassium in their diet. (23) The results from a 12-year study reports that a high amount of potassium from food may protect against stroke-related death. (24)


Magnesium

Results from the Nurses Health Study reported that magnesium in the diet was linked to a decreased occurrence of ischemic stroke in women. (25) Studies also reported that magnesium affects stroke risk in men, (26) and that men with the highest amount of magnesium in their diet have a 30 percent lower risk of stroke compared to men consuming the lowest levels. (27) It has also been reported that patients with ischemic stroke have lower magnesium in the blood and spinal fluid compared with healthy patients. (28)


Vitamin C

Free radical damage probably plays a role in the nerve damage caused by strokes. Several antioxidant nutrients, including ascorbic acid, are associated with the amount of nerve damage following stroke. These results mean that antioxidants activity may be an important factor providing nerve protection from stroke. (29)

Data from the Second National Health and Nutrition Examination Survey (NHANES-II) reported that an increase in ascorbic acid was linked to an 11 percent decrease in the occurrence of heart disease and stroke. (30) Data from the 30-year Chicago Western Electric Study reported that those individuals with the highest amount of vitamin C in their diet had a 29 percent decrease in the occurrence and related death from strokes compared to individuals with the lower amounts of vitamin C in their diet. (31) In a review of studies from 1966 to 1996, researchers found that vitamin C provided protection against strokes. (32)


Acetyl-L-Carnitine (ALC)

Results from animal studies report that treatment with acetyl-L-carnitine improved recovery and prevented weight loss in the animals that had strokes. (33) In human patients who suffered an ischemic stroke at least six months before the study, acetyl-L-carnitine resulted in an increase in brain blood flow. (34)


Selenium

In a study of 1,110 men in Finland between the ages of 55 to 74 who did not have heart disease, there was a strong connection between low selenium levels and strokes. (35)


Beta-Carotene

Data from the 30-year Chicago Western Electric Study reported the effect of antioxidants on the risk of strokes. Individuals with the highest amount of beta-carotene in their diet had a 16 percent decrease in the occurrence and rate of death from strokes compared to individuals with the lowest amount of beta-carotene in their diet. (36)


Policosanol

Policosanol is a natural mixture from sugar cane wax that has cholesterol-lowering effects. (37) , (38) , (39) , (40) The lowering of blood cholesterol can be directly connected to a decrease in stroke. (41) , (42)

Policosanol has also been reported to protect against the development of atherosclerotic lesions in laboratory animal studies, (43) thus providing a possible therapeutic effect in brain blood vessel diseases. (44)

Herbal Suplementation


Ginkgo

Ginkgo is among the oldest living species on earth and has been used as a medicine worldwide for centuries. It is the most frequently prescribed herb in Europe. It is reported to improve circulation in the elderly. (45) , (46) This can lead to improved memory, a delay in the start of Alzheimer's disease, (47) and a decrease in senile dementia, (48) tinnitus (ringing in the ears), (49) and vertigo (dizziness). (50) Memory improvement has also been reported in younger people as well.

The main active ingredients of ginkgo are the flavoglycosides. These compounds act as free radical scavengers or antioxidants. (51) Ginkgo is also reported to slow down platelet activating factor (PAF), which keeps platelets from sticking together, possibly improving circulation, decreasing the formation of blood clots, thereby decreasing the risk of stroke. Ginkgo has also been reported to dilate blood vessels and have additional effects on the blood vessels to improve circulation. (52) , (53) It may also remove toxins that occur during ischemic episodes. (54) Gingko reportedly acts as a tonic for the circulatory system. It may increase blood flow to the brain and bring more nutrition to the brain. (55) Ginkgo may also affect acetylcholine in the brain, improving cognitive function. (56)


Hawthorn

Hawthorn is used to dilate blood vessels and increase the circulation. (57) It has been used by doctors in Europe for a variety of heart and circulation conditions. It is used as a tonic, especially for the elderly, where mitral stenosis (a narrowing in the area of the mitral valve in the heart) and minor heart failure may be present. Studies have reported a decrease in blood pressure due to arteriosclerosis (hardening of the arteries) and chronic nephritis (inflammation of the kidney) with the use of hawthorn. (58) It is also used for Raynaud’s disease.

Hawthorn is reported to be able to regulate both low and high blood pressure. Its active ingredients reportedly dilate blood vessels. (59) It is also used to decrease angina attacks. Hawthorn affects the circulation in the heart and increases the force of the heartbeat. (60) Hawthorn flower and leaf have a slight diuretic effect (removes fluid from the body) which may help lower high blood pressure, so the berry may be preferred in managing hypotension (low blood pressure). Laboratory studies have reported that hawthorn berry may also remove atherosclerotic plaque (responsible for hardening of the arteries). (61)


Cordyceps

Cordyceps is a unique black mushroom that takes nutrients from and grows only on a caterpillar found in the high altitudes of Tibet and China. Cordyceps has been used in traditional Chinese medicine as the herb of choice for lung and kidney problems, and as a general tonic for promoting long life, vitality, and endurance. (62) Cordyceps is beneficial in helping individuals with decreased energy increase their level of activity. Cordyceps has been used in humans for centuries as a tonic for improving performance and vitality, by increasing the use of oxygen by the cardiopulmonary (heart and lungs) system.

Cordyceps may provide value in stroke cases because of its ability to bring more oxygen to ischemic areas. Cordyceps may increase physical strength and endurance. (63) , (64) Cordyceps has traditionally been used to improve breathing in individuals with decreased lung function, such as asthma and bronchitis. (65) Cordyceps has been reported to have anticancer effects. (66) , (67) , (68) Cordyceps has been used to decrease the kidney problems that may develop from some drugs, (69) , (70) and in individuals with chronic kidney failure. (71) Cordyceps was also reported to protect stem cells and red blood cells during chemotherapy and radiation. (72)

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