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Stroke (more information)

Overview

Stroke is a type of cardiovascular disease. Cardiovascular refers to the heart and blood vessels.

A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot (ischemic stroke) or burst (hemorrhagic stroke). When that happens, part of the brain cannot get the blood and oxygen it needs, so it starts to die. The effects of a stroke depend on which part of the brain is injured, and how severely it is injured. Strokes may cause sudden weakness, loss of sensation, or difficulty with speaking, seeing, or walking. Since different parts of the brain control different areas and functions, it is usually the area immediately surrounding the stroke that is affected.

There are three different types of stroke: ischemic, hemorrhagic, and transient ischemic attacks.

Ischemic stroke is the most common, accounting for 83% of all strokes (from stroke assoc). It usually results from an obstruction, usually a blood clot. These clots are called cerebral thrombus or cerebral embolism.

  • Cerebral thrombus refers to a thrombus (blood clot) that develops at the clogged part of the vessel.
  • Cerebral embolism refers generally to a blood clot that forms at another location in the circulatory system, usually the heart and large arteries of the upper chest and neck. A portion of the blood clot breaks loose, enters the bloodstream and travels through the brain's blood vessels until it reaches vessels too small to let it pass. Atrial fibrillation (irregular heartbeat) also causes cerebral embolism. It creates conditions where clots can form in the heart, dislodge and travel to the brain.

Hemorrhagic stroke accounts for 17% of stroke cases. It is caused by a weakened vessel that ruptures and bleeds into the surrounding brain. The blood accumulates and compresses the surrounding brain tissue. Hemorrhagic stroke can be of two types: intracerebral hemorrhage or subarachnoid hemorrhage.

Two types of weakened blood vessels usually cause hemorrhagic stroke: aneurysms and arteriovenus malformations (AVMs):

  • An aneurysm is a ballooning of a weakened region of a blood vessel. If left untreated, the aneurysm continues to weaken until it ruptures and bleeds into the brain.
  • An arteriovenus malformation (AVM) is a cluster of abnormally formed blood vessels. Any one of these vessels can rupture, also causing bleeding into the brain.

The third type of stroke is known as transient ischemic attacks (TIAs). These are minor or warning strokes. If you experience TIAs, you will have stroke symptoms and a blood clot will form. However, the blood clot occurs for a short time and tends to go away by itself.

Even though symptoms disappear after a short time, TIAs are strong indicators of a possible major stroke. Steps should be taken immediately to prevent a stroke.

For more on Types of Strokes see "What are the Types of Stroke?" www.strokeassociation.org/presenter.jhtml?identifier=1014

Types of Stroke www.strokecenter.org/pat/stroke_tyupes.htm

Risk factors

The American Stroke Association has identified several factors that increase your risk of stroke. The more risk factors you have, the greater the chance that you will have a stroke. Some risk factors are uncontrollable, such as increasing ages, family history, and race. But others you can control or change to reduce your risk:

Increasing age -- The chance of having a stroke more than doubles for each decade of life after age 55. While stroke is common among the elderly, many people under 65 also have strokes.

Sex -- The latest data show that, overall, the incidence and prevalence of stroke are about equal for men and women. However, at all ages, more women than men die of stroke.

Heredity (family history) and race -- The chance of stroke is greater in people who have a family history of stroke. African Americans have a much higher risk of disability and death from a stroke than whites, in part because blacks have a greater incidence of high blood pressure, a major stroke risk factor.

Prior stroke -- The risk of stroke for someone who has already had one is many times that of a person who has not.

High blood pressure -- High blood pressure is the most important risk factor for stroke. In fact, stroke risk varies directly with blood pressure. Many people believe the effective treatment of high blood pressure is a key reason for the accelerated decline in the death rates for stroke.

Cigarette smoking -- In recent years, studies have shown cigarette smoking to be an important risk factor for stroke. The nicotine and carbon monoxide in cigarette smoke damage the cardiovascular system in many ways. The use of oral contraceptives combined with cigarette smoking greatly increases stroke risk.

Diabetes mellitus -- Diabetes is an independent risk factor for stroke and is strongly correlated with high blood pressure. While diabetes is treatable, having it increases a person's risk of stroke. People with diabetes often also have high cholesterol and are overweight, increasing their risk even more.

Carotid artery disease -- The carotid arteries in your neck supply blood to your brain. A carotid artery damaged by atherosclerosis (a fatty buildup of plaque in the artery wall) may become blocked by a blood clot, which may result in a stroke. If you have a diseased carotid artery, your healthcare provider may hear an abnormal sound in your neck, called a bruit (BROO ee), when listening with a stethoscope.

Heart disease -- People with heart problems have more than twice the risk of stroke as those whose hearts work normally. Atrial fibrillation (the rapid, uncoordinated beating of the heart's upper chambers) in particular raises the risk for stroke. Heart attack is also the major cause of death among stroke survivors.

Transient ischemic attacks (TIAs) -- TIAs are "mini strokes" that produce stroke-like symptoms but no lasting damage. They are strong predictors of stroke. A person who's had one or more TIAs is almost 10 times more likely to have a stroke than someone of the same age and sex who hasn't.

High red blood cell count -- A moderate or marked increase in the red blood cell count is a risk factor for stroke. The reason is that more red blood cells thicken the blood and make clots more likely.

There are other factors that can affect the risk of stroke:

  • Season and climate. Most strokes occur in extremely cold or hot weather conditions.
  • Socioeconomic. Studies have shown that people with lower income levels and education have an increased risk for stroke.
  • Excessive alcohol consumption. Excessive drinking (an average of more than one drink per day for women and more than two drinks per day for men) and binge drinking can raise blood pressure, contribute to obesity, high triglycerides, cancer and other diseases, cause heart failure and lead to stroke.
  • Certain kinds of drug abuse. Intravenous drug abuse carries a high risk of stroke from cerebral emboli. Cocaine use has been closely related to strokes, heart attacks and a variety of other cardiovascular complications. Some of them have been fatal even in first-time cocaine users.

Other risk factors are secondary risk factors. They affect the risk of stroke indirectly by increasing the risk of heart disease. They include:

  • High blood cholesterol and lipids
  • Physical inactivity
  • Obesity or overweight

Prevention and Planning Ahead

Many strokes can be prevented by controlling risk factors and treating other medical conditions that can lead to stroke. Some ways you can control your risk factors include:

  • Having regular medical checkups.
  • Working with doctor to control high blood pressure; this is especially true if you have diabetes.
  • Not smoking. If you do smoke, quit. Daily cigarette smoking can increase the risk of stroke by 250%. (qtd. In webmd)
  • Taking cholesterol-lowering medications called statins if you have high cholesterol or have had a heart attack. (qtd. In webmd)

Seek immediate medical attention if you have symptoms of a transient ischematic attack (TIA). A TIA is a strong indicator of stroke.

  • If your doctor diagnosed you with atherosclerosis, check with him or her about whether you should take an aspirin each day and/or medication to lower your cholesterol. If you have already had a stroke, taking an aspirin daily can reduce the risk of a second stroke, TIA, or carotid endarterectomy surgery.
  • If your doctor hears a swishing sound-a bruit-when listening to the blood flow through the large blood vessels in your neck (carotid arteries), ask whether you need further testing (usually carotid ultrasonography). You may need aspirin or surgery to reopen a blocked carotid artery.

Warning Signs & Symptoms

Learn to recognize a stroke and act quickly:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  • Sudden confusion, trouble speaking or understanding
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking, dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause

Call 9-1-1 immediately if you experience symptoms. Do not wait!

Diagnosis

To diagnose stroke your doctor will ask you questions about the symptoms you are having now or have had in the past, previous medical problems or operations, and illnesses which run in your family. Be sure to bring a current list of all the medicines you take (prescription and non-prescriptions). If your symptoms only lasted awhile, your doctor may want to speak with someone who was with you at the time.

Next, you doctor will perform a physical exam. Your doctor will check your pulse and blood pressure, and examine the rest of your body (heart, lungs, etc). The neurological examination includes detailed tests of your muscles and nerves. The doctor will check your strength, sensation, coordination and reflexes. In addition, you will be asked questions to check your memory, speech and thinking.

If your doctor needs further information, he or she may order the following test:

  • Blood tests
  • CT scan
  • MRI scan
  • Carotid Doppler
  • Electrocardiogram
  • Cerebral arteriogram

You may also be referred to a medical specialist in brain disorders (neurologist), brain surgery (neurosurgery) or another area.

For more on tests see Lab Tests and Procedures Used for Stroke Diagnosis www.strokecenter.org/pat/diagnosis/tests.htm

Treatment/Intervention

It is important to seek treatment at the first sign of a stroke. Just as with a heart attack, permanent damage develops within the first few hours. The shorter the amount of time blood flow tin the brain is blocked, the less permanent damage will develop. Early treatment focuses on preventing life-threatening complications.

Treatment for stroke may include medication, surgery, or rehabilitative therapy and depends on the type of stroke.

Ischemic Stroke

Treatment for ischemic strok depends on two things: the location of a clot blocking blood flow to the brain and the caused of the blood clot. If treatment is received within the first three hours of an ischemic stroke, a clot dissolving drug, tissue plasminogen activator (t-PA) may be used. Antiplatelet and anticoagulants may also be used to slow blood clotting if the clot has formed in the heart or another part of the body and blocks blood supply to the brain. If conditions, such as atrial fibrillation or abnormal heart valve, caused the blood clot, these conditions will also need to be treated. Surgery may be needed if there is a blockage of the large blood vessel in the neck (carotid artery). This surgical procedure, a carotid endarterectomy, will remove the plaque and reopen the blood vessel. This surgery is normally conducted after a patient has recovered from a stroke.

Hemorrhagic Stroke

  • Medication and occasionally surgery is used to treat hemorrhagic strokes. Medication is used to:
    • Prevent blood pressure from getting either too high (which worsens bleeding) or too low (which reduces blood flow to the brain).
    • Lower pressure inside the brain. Increased pressure on the brain often develops when the brain swells after a person suffers a large hemorrhagic stroke. This swelling of the brain usually develops quickly and becomes most severe 1 to 4 days after the stroke.
      • In addition to medication, steps to reduce pressure on the brain include:
      • Keeping the head of the bed in a partially upright position.
      • Closely monitoring for signs of increased pressure on the brain, such as restlessness, confusion, difficulty following commands, and complaints of headache.
      • Having the person avoid straining by avoiding excessive coughing, vomiting, or lifting. Also, the person needs to avoid straining when passing stool or when using his or her arms to change position.
  • Prevent or treat seizures.
  • Manage body temperature. Acetaminophen (such as Tylenol) may be used to treat fever.
  • Prevent blood clots. Special stockings may also be used to help prevent blood clots while a person is in bed.

Surgery generally is not used to control mild to moderate bleeding resulting from a hemorrhagic stroke. However, if a large amount of bleeding has occurred and the person is rapidly getting worse, surgery may be needed to remove the blood that has built up inside the brain and to lower pressure inside the person's head.1

Alternative Medicine

Frequently Asked Questions

Q: What is stroke?

A: Stoke is a cardiovascular disease. It affects the arteries leading to and within the brain. A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts. When that happens, part of the brain cannot get the blood (and oxygen) it needs, so it starts to die.

Q: What are the three types of strokes?

A: There are three types of strokes: ischemic, hemorrhagic, and transient ischemic attacks. Ischemic attacks account for 83% of all strokes and usually result from a blood clot. Hemorrhagic strokes are caused by a weakened vessel that ruptures and bleeds into the surround brain. Transient ischemic attacks or "mini strokes" are warning strokes. If you experience a TIA, you will have stroke symptoms and a blood clot will form. However, the blood clot occurs for a short time and tends to go away by itself.

Q: Why do African Americans have a higher risk of disability and death from stroke than whites?

A: African Americans have a higher risk of disability and death from stroke than whites, in part because black have a greater incidence of high blood pressure, a major stroke risk factor.

Q: Does just having diabetes increase my risk of suffering a stroke?

A: Diabetes is an independent risk factor for stroke and is strongly correlated with high blood pressure. While diabetes is treatable, having it increases a person's risk of stroke. People with diabetes often also have high cholesterol and are overweight, increasing their risk even more.

Q: Can drinking alcohol increase my risk for stroke?

A: Yes. Excessive alcohol consumption. Excessive drinking (an average of more than one drink per day for women and more than two drinks per day for men) and binge drinking can raise blood pressure, contribute to obesity, high triglycerides, cancer and other diseases, cause heart failure and lead to stroke.

Q: Can drug use cause a stroke?

A: Yes. Intravenous (using a needle) drug abuse greatly increases the risk of stroke. Cocaine has been closely related to strokes. Some to them have been fatal even in first-time drug users.

Q: What are the symptoms of stroke?

A: Sudden numbness or weakness of the face, arm or leg, especially on one side of the body. Sudden confusion, trouble speaking or understanding. Sudden trouble seeing in one or both eyes. Sudden trouble walking, dizziness, loss of balance or coordination. Sudden, severe headache with no known cause.

Q: Sometimes I feel a sudden numbness or weakness in my face, arm or leg, especially on one side of my body? What is happening to me?

A: If the numbness goes away after a short period of time, it may be signaling a transient ischemic attack (TIA). TIAs are often clear warning signs of a stroke. See your doctor immediately.

Q: Sometimes I have trouble seeing in one eye. Does this having anything to do with stroke?

A: It may. Sudden trouble seeing in one or both eyes is a symptom of stroke. See your physician to check this out.

For more on stroke visit:

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