Types of stroke
- Ischemic stroke: About 80% of strokes are ischemic strokes. Blood clots or other particles such as cholesterol may block arteries to the brain and cause severely reduced blood flow (ischemia). This deprives the brain cells of necessary oxygen and nutrients, and may lead to cell death within minutes. The most common ischemic strokes include thrombotic stroke and embolic stroke.
- Thrombotic stroke: This type of stroke occurs when a blood clot (thrombus) forms in one of the arteries that supply blood to the brain. Areas damaged by atherosclerosis (hardening of the arteries) are highly susceptible to developing a blood clot. Arteries in the brain or in the neck (carotid arteries) that carry blood to the brain are susceptible. An ischemic stroke may also be caused by plaque (deposits of fat, protein, and other particles in the blood) that narrows or completely clogs an artery. This narrowing is called stenosis.
- Embolic stroke: An embolic stroke occurs when a blood clot or other particle forms in a blood vessel away from the brain (such as the heart) and travels through the blood to eventually lodge in narrower brain arteries (called an embolus). Emboli may often be caused by irregular beating in the heart's two upper chambers (atrial fibrillation). This abnormal heart rhythm can lead to stagnant (sluggish) blood flow and the formation of blood clots.
- Hemorrhagic stroke: Hemorrhage means bleeding. Hemorrhagic stroke occurs when a blood vessel in the brain leaks or breaks open (ruptures). Hemorrhages can result from a number of conditions that affect the blood vessels, including uncontrolled high blood pressure (hypertension) and weak spots in the blood vessel walls (aneurysms). A less common cause of hemorrhage is the rupture of an arteriovenous malformation (AVM), or a malformed tangle of thin-walled blood vessels present at birth. There are two types of hemorrhagic stroke including intracerebral hemorrhage and subarachnoid hemorrhage.
- Intracerebral hemorrhage: In this type of stroke, a blood vessel in the brain bursts and spills into the surrounding brain tissue, damaging cells. Brain cells beyond the leak are deprived of oxygen and are also damaged. High blood pressure is the most common cause of this type of hemorrhagic stroke, causing small arteries inside the brain to become fragile and susceptible to tearing and rupture.
- Subarachnoid hemorrhage: In this type of stroke, bleeding starts in a large artery on or near the membrane surrounding the brain and spills into the space between the surface of the brain and skull. A subarachnoid hemorrhage is often signaled by a sudden, severe "thunderclap" headache. This type of stroke is commonly caused by the rupture of an aneurysm, which can develop with age or result from a genetic predisposition. After a subarachnoid hemorrhage, vessels may go into vasospasm, in which arteries near the hemorrhage widen and narrow erratically, causing brain cell damage by further restricting or blocking blood flow to portions of the brain.
Lifestyle changes and prevention
- Guidelines for stroke prevention have been developed by the American Heart Association. Primary prevention focuses on preventing a stroke, while secondary prevention focuses on preventing stroke in those with a history of stroke or TIA.
- High blood pressure (hypertension) control: One of the most important interventions that can be made in prevention of strokes is the reduction of high blood pressure. Lowering a patient's blood pressure can help prevent a subsequent transient ischemic attack or stroke. Exercising, managing stress, maintaining a healthy weight, and limiting sodium and alcohol intake are all ways to keep hypertension in check. Medications to treat hypertension, such as diuretics, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers may also be utilized.
- Cholesterol and saturated fat intake reduction: Eating less cholesterol and fat, especially saturated fat, may help prevent further buildup of plaque in the arteries. Medications from the "statin" drug-class, which work by inhibiting an enzyme (HMG-CoA reductase) that is used to make cholesterol in the body may be prescribed to help reduce unhealthy cholesterol levels.
- Smoking cessation: Quitting smoking reduces the risk of stroke. Smoking can double or triple the chances of having a stroke.
- Diabetes control: Managing diabetes with diet, exercise, weight control and medication is essential. Strict control of blood sugar may reduce damage to the brain in the case of a stroke. Increases in blood sugar levels can damage fragile blood vessels in the body, including the brain, and increase the risk of rupture (breaking open).
- Weight control: Being overweight contributes to other risk factors for stroke, such as high blood pressure, cardiovascular disease and diabetes. Weight loss of as little as 10 pounds may lower blood pressure and improve cholesterol levels.
- Exercise: Exercise can lower blood pressure, increase the level of HDL cholesterol (good cholesterol), and improve the overall health of blood vessels and heart. It also helps control weight, control diabetes and reduce stress. Thirty minutes daily of exercise is normally recommended, but each individual should develop an exercise program for his/her own physical ability. A study reported that men with the highest degree of physical fitness were more than three times less likely than men with the lowest degree of physical fitness to have a stroke.
- Stress management: Stress can cause an increase in blood pressure along with increasing the blood's tendency to clot. Finding ways to decrease stress is important in preventing stroke, especially if an individual has other risk factors.
- Alcohol drinking: Alcohol can be both a risk factor and a preventive measure for stroke. Binge drinking and heavy alcohol consumption increase the risk of high blood pressure and of ischemic and hemorrhagic strokes. However, drinking small to moderate amounts of alcohol (1-2 drinks a day) can increase HDL cholesterol and decrease the blood's clotting tendency. Both factors can contribute to a reduced risk of ischemic stroke.
- Illicit drugs elimination: Street drugs, such as methamphetamine (crystal meth, ice), cocaine, and ecstasy are established risk factors for a transient ischemic attack (TIA) or a stroke.
- Dietary modification: Eat healthy foods. A healthy diet should include five or more daily servings of fruits and vegetables, foods rich in soluble fiber (such as oatmeal and beans), foods rich in calcium (dairy products, spinach), soy products (such as tempeh, miso, tofu and soy milk), and foods rich in omega-3 fatty acids, including cold-water fish, such as salmon, mackerel and tuna. Pregnant women and women who plan to become pregnant in the next several years should limit their weekly intake of cold-water fish because of the potential for mercury contamination, which can cause fetal damage.
Copyright © 2011 Natural Standard (www.naturalstandard.com)
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.