STROKE

General Infomation
Definition: 

A stroke occurs when the blood supply to a part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen and nutrients. Within a few minutes, brain cells begin to die.
Stroke is a medical emergency, and prompt treatment of a stroke is crucial. Early treatment can minimize damage to your brain and potential stroke complications.
The good news is that strokes can be treated, and many fewer Americans now die of strokes than was the case 20 or 30 years ago. Improvement in the control of major risk factors for stroke — high blood pressure, smoking and high cholesterol — is likely responsible for the decline.

Symptoms: 

Watch for these stroke symptoms if you think you or someone else is having a stroke:
• Trouble with walking. If you're having a stroke, you may stumble or have sudden dizziness, loss of balance or loss of coordination.
• Trouble with speaking. If you're having a stroke, you may slur your speech or may not be able to come up with words to explain what is happening (aphasia). Try to repeat a simple sentence. If you can't, you may be having a stroke.
• Paralysis or numbness on one side of the body. If you're having a stroke, you may have sudden numbness, weakness or paralysis on one side of the body. Try to raise both your arms over your head at the same time. If one arm begins to fall, you may be having a stroke.
• Trouble with seeing. If you're having a stroke, you may suddenly have blurred or blackened vision or may see double.
• Headache. A sudden, severe "bolt out of the blue" headache or an unusual headache, which may be accompanied by a stiff neck, facial pain, pain between your eyes, vomiting or altered consciousness, sometimes indicates you're having a stroke.
For most people, a stroke gives no warning. But one possible sign of an impending stroke is a transient ischemic attack (TIA). A TIA is a temporary interruption of blood flow to a part of your brain. The signs and symptoms of TIA are the same as for a stroke, but they last for a shorter period — several minutes to 24 hours — and then disappear, without leaving apparent permanent effects. You may have more than one TIA, and the recurrent signs and symptoms may be similar or different.
A TIA may indicate that you're at risk of a full-blown stroke. People who have had a TIA are much more likely to have a stroke than are those who haven't had a TIA.
When to see a doctor
If you notice any signs or symptoms of a stroke or TIA, get medical help right away. A TIA may seem like a passing event. But it's an important warning sign — and a chance to take steps that may prevent a stroke.
If someone appears to be having a stroke, watch the person carefully while waiting for an ambulance. You may need to take additional actions in the following situations:
• If the person stops breathing, begin mouth-to-mouth resuscitation.
• If vomiting occurs, turn the person's head to the side. This can prevent choking.
• Don't let the person eat or drink anything.
Every minute counts when it comes to treating a stroke or TIA. In fact, sometimes a stroke is referred to as a "brain attack" to convey that, similar to a heart attack, quick care is important. So, don't wait to see if the signs and symptoms go away. The longer a stroke goes untreated, the greater the damage and potential disability. The success of most stroke treatments depends on how soon a person is seen by a doctor in a hospital emergency room after signs and symptoms begin.

Causes & Complication
Causes: 

A stroke occurs when there's a problem with the amount of blood in your brain. The cause of the main type of stroke — ischemic stroke — is too little blood in the brain. The cause of the other type of stroke — hemorrhagic stroke — is too much blood within the skull.
Ischemic stroke
About 80 percent of strokes are ischemic strokes. They occur when the arteries to your brain are narrowed or blocked, causing severely reduced blood flow (ischemia). This deprives your brain cells of oxygen and nutrients, and cells may begin to die within minutes. The most common ischemic strokes are:
• Thrombotic stroke. This type of stroke occurs when a blood clot (thrombus) forms in one of the arteries that supply blood to your brain. A clot usually forms in areas damaged by atherosclerosis — a disease in which the arteries are clogged by fatty deposits (plaques). This process can occur within one of the two carotid (kuh-ROT-id) arteries of your neck that carry blood to your brain, as well as in other arteries of the neck or brain.
• Embolic stroke. An embolic stroke occurs when a blood clot or other particle forms in a blood vessel away from your brain — commonly in your heart — and is swept through your bloodstream to lodge in narrower brain arteries. This type of blood clot is called an embolus. It's often caused by irregular beating in the heart's two upper chambers (atrial fibrillation). This abnormal heart rhythm can lead to poor blood flow and the formation of a blood clot.
Hemorrhagic stroke
"Hemorrhage" is the medical word for bleeding. Hemorrhagic stroke occurs when a blood vessel in your brain leaks or ruptures. Hemorrhages can result from a number of conditions that affect your blood vessels, including uncontrolled high blood pressure (hypertension) and weak spots in your blood vessel walls (aneurysms). A less common cause of hemorrhage is the rupture of an arteriovenous malformation (AVM) — an abnormal tangle of thin-walled blood vessels, present at birth. There are two types of hemorrhagic stroke:
• 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 blood and are also damaged. High blood pressure is the most common cause of this type of hemorrhagic stroke. Over time, high blood pressure can cause small arteries inside your brain to become brittle and susceptible to cracking and rupture.
• Subarachnoid hemorrhage. In this type of stroke, bleeding starts in a large artery on or near the surface of the brain and spills into the space between the surfaces of your brain and your skull. This type of 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 be genetically inherited. After the hemorrhage, the blood vessels in your brain may widen and narrow erratically (vasospasm), causing brain cell damage by further limiting blood flow to parts of your brain.
Transient ischemic attack (TIA) and stroke
A transient ischemic attack (TIA, or ministroke) is a brief episode of symptoms similar to those you'd have in a stroke. The cause of a transient ischemic attack is a temporary decrease in blood supply to part of your brain. Most attacks last just a few minutes.
TIA has the same cause as an ischemic stroke. In ischemic strokes, which are the most common type of stroke, a clot blocks the blood supply to part of your brain. But in contrast to a stroke, which involves a more prolonged lack of blood supply and causes some permanent damage to your brain tissue, a TIA doesn't leave lasting effects to your brain. Still, if you've had a TIA, it means there's likely a blocked or narrowed artery leading to your brain, putting you at a greater risk of a full-blown stroke that could cause more permanent damage. If you're having a TIA, get emergency medical treatment and make sure your regular physician knows about it.

Risk Factors: 

Many factors can increase your risk of a stroke. A number of these factors can also increase your chances of having a heart attack. Stroke risk factors include:
• A family history of stroke, heart attack or TIA
• Being age 55 or older
• High blood pressure — a systolic blood pressure of 140 millimeters of mercury (mm Hg) or higher, or a diastolic pressure of 90 mm Hg or higher
• High cholesterol — a total cholesterol level of 200 milligrams per deciliter (mg/dL), or 5.2 mmol/L, or higher
• Cigarette smoking
• Diabetes
• Obesity — a body mass index of 30 or higher
• Cardiovascular disease, including heart failure, a heart defect, heart infection, or abnormal heart rhythm
• Previous stroke or TIA
• High levels of homocysteine, an amino acid, in your blood
• Use of birth control pills or other hormone therapy
Other factors that can increase your risk of stroke include heavy or binge drinking and the use of illicit drugs such as cocaine.
Although men and women have strokes at about the same rate, women more often die of strokes than do men. Blacks are more likely to have strokes than are people of other races.

Complications: 

Depending on how long the brain suffers a lack of blood flow, a stroke can sometimes cause temporary or permanent disabilities. Stroke complications differ depending what part of the brain was affected and may include:
• Paralysis or loss of muscle movement. Sometimes, a lack of blood flow to the brain can cause a person to become paralyzed on one side of the body, or lose control of certain muscles, such as those on one side of the face. With physical therapy, you may see improvement in muscle movement or paralysis.
• Difficulty talking or swallowing. A stroke may cause a person to have less control over the way the muscles in the mouth move, making it difficult to talk, swallow or eat. A person may also have difficulty speaking because a stroke has caused aphasia, a condition in which a person has difficulty expressing thoughts through language. Therapy with a speech and language pathologist may improve this disability.
• Memory loss or troubles with understanding. It's common that people who suffer strokes have some memory loss. Others may develop difficulty understanding concepts. This complication may improve with rehabilitation therapies.
• Pain. Some people who have a stroke may have pain, numbness, or other strange sensations in parts of their body affected by stroke. For example, if a stroke causes you to lose feeling in your left arm, you may have an uncomfortable tingling sensation in that arm. You may also be sensitive to temperature changes, especially extreme cold. This is called central stroke pain or central pain syndrome (CPS). This complication may improve with time, but because the pain is caused by a problem in the brain instead of a physical injury, there are few medications to treat CPS.
People who have a stroke may also become withdrawn and less social. They may lose the ability to care for themselves and may need a caretaker to help them with their grooming needs and daily chores after a stroke.
As with any brain injury, the success of treating these complications will vary from person to person.

Tests
Tests and Diagnosis: 

If you've had a previous stroke or TIA or think you're at risk of stroke, talk with your doctor about screening tests.
Before treating a stroke, your doctor must figure out what type of stroke you're having and what parts of your brain it's affecting. Other possible causes of your symptoms, such as a tumor, also need to be ruled out as a cause.
The following are most often used as screening tools to determine your risk, but they may also be used as diagnostic tools if you're having a stroke:
• Physical examination and tests. Your doctor may check for risk factors of stroke, including high blood pressure, high cholesterol levels, diabetes and high levels of the amino acid homocysteine. Your doctor may also use a stethoscope to listen for a whooshing sound (bruit) over your arteries that may indicate atherosclerosis.
• Carotid ultrasound. In this procedure, a wand-like device (transducer) sends high-frequency sound waves into your neck. The sound waves pass through tissue and then return, creating on-screen images that show any narrowing or clotting in your carotid arteries.
• Arteriography. This procedure gives a view of arteries in your brain not normally seen in X-rays. Your doctor inserts a thin, flexible tube (catheter) through a small incision, usually in your groin. The catheter is manipulated through your major arteries and into your carotid or vertebral artery. Then your doctor injects a dye through the catheter to provide X-ray images of your arteries.
• Computerized tomography (CT). In computerized tomographic angiography (CTA), a dye is injected into your vein and X-ray beams create a 3-D image of the blood vessels in your neck and brain. Doctors use CTA to look for aneurysms or arteriovenous malformations and to evaluate arteries for narrowing. CT scanning, which is done without dye, can provide images of your brain and show hemorrhages, but without as much detailed information about the blood vessels.
• Magnetic resonance imaging (MRI). Using a strong magnetic field, an MRI can generate a 3-D view of your brain. This test can detect brain tissue damaged by an ischemic stroke. Magnetic resonance angiography (MRA) uses the magnetic field and a dye injected into your veins to evaluate arteries in your neck and brain.
• Echocardiography. Your doctor can use this ultrasound technology to make images of your heart to see if an embolus from your heart has caused your stroke. Your doctor may need to use transesophageal echocardiography (TEE) to see your heart clearly. During this procedure, you swallow a flexible probe with a transducer built into it. From there, the probe travels to your esophagus — the tube that connects the back of your mouth to your stomach. Because your esophagus is directly behind your heart, very clear, detailed ultrasound images can be created, allowing a better view of blood clots, which might not be seen clearly in a traditional echocardiography exam.

Medication & Prevation
Treatments and Drugs: 

Getting prompt medical treatment for stroke is important. Treatment itself depends on the type of stroke.
Ischemic stroke
To treat an ischemic stroke, doctors must quickly restore blood flow to your brain.
Emergency treatment with medications. Therapy with clot-busting drugs must start within three hours. Quick treatment not only improves your chances of survival, but may also reduce the amount of complications resulting from the stroke. You may be given:
• Aspirin. Aspirin is the best-proven immediate treatment after a stroke to reduce the likelihood of having another stroke. In the emergency room, it's likely you'll be given a dose of aspirin. The dose may vary, but if you already take a daily aspirin for its blood-thinning effect, you may want to make a note of that in your purse or wallet on an emergency medical card so that the doctors will know if you've already had some aspirin. Do not take aspirin before you go to the hospital. If you are having a hemorrhagic stroke, taking aspirin could worsen the bleeding.
Other blood-thinning drugs, such as warfarin (Coumadin) and heparin also may be given, but they aren't as commonly used as aspirin.
• Tissue plasminogen activator. Some people who are having a stroke can benefit from an injection of tissue plasminogen activator (TPA). TPA is a potent clot-busting drug that helps some people who have had stroke recover more fully. However, the drug can only be given to patients within a three-hour window of the stroke occurring, and it can only be given in situations in which doctors are certain that giving TPA will not worsen bleeding in the brain. TPA cannot be given to people who are having a hemorrhagic stroke.
Surgical and other procedures. Your doctor may recommend a procedure to open up an artery that's moderately to severely narrowed by plaques. This may include:
• Carotid endarterectomy. In this procedure, a surgeon removes plaques that block the carotid arteries that run up both sides of your neck to your brain. The blocked artery is opened, the plaques are removed and your surgeon closes the artery. The procedure may reduce your risk of ischemic stroke. However, in addition to the usual risks associated with any surgery, a carotid endarterectomy itself can also trigger a stroke or heart attack by releasing a blood clot or fatty debris, although surgeons now place filters (distal protection devices) at strategic points in your bloodstream to "catch" any material that may break free during the procedure.
• Angioplasty and stents. Used less commonly than carotid endarterectomy, angioplasty can widen the inside of an artery leading to your brain, usually the carotid artery. In this procedure, a balloon-tipped catheter is maneuvered into the obstructed area of your artery. The balloon is inflated, compressing the plaques against your artery walls. A metallic mesh tube (stent) is usually left in the artery to prevent recurrent narrowing. Angioplasty and stenting of carotid arteries may be an appropriate stroke prevention option for some people who've had a stroke or transient ischemic attack (TIA) but can't undergo surgery. Intracranial stenting is similar to stenting the carotid arteries. Using a small incision in the groin, doctors thread a catheter through the arteries and into the brain. Sometimes they use angioplasty to widen the affected area first; in other cases, angioplasty is not used before stent placement.
Hemorrhagic stroke
Surgery may be used to treat a hemorrhagic stroke or prevent another one. The most common procedures — aneurysm clipping and arteriovenous malformation (AVM) removal — carry some risks. Your doctor may recommend one of these procedures if you're at high risk of spontaneous aneurysm or AVM rupture:
• Aneurysm clipping. A tiny clamp is placed at the base of the aneurysm, isolating it from the circulation of the artery to which it's attached. This can keep the aneurysm from bursting, or it can prevent re-bleeding of an aneurysm that has recently hemorrhaged. The clip will stay in place permanently.
• Coiling (aneurysm embolization). In an embolization procedure, a catheter is maneuvered into the aneurysm. A tiny coil is pushed through the catheter and positioned inside the aneurysm. The coil fills the aneurysm, causing clotting and sealing the aneurysm off from connecting arteries.
• Surgical AVM removal. It's not always possible to remove an AVM if it's too large or if it's located deep within the brain. Surgical removal of a smaller AVM from a more accessible portion of the brain, though, can eliminate the risk of rupture, lowering the overall risk of hemorrhagic stroke.
Stroke recovery and rehabilitation
Stroke survivors who go home to a healthy spouse or other companion are more likely to become independent and productive again. Encouragement and early treatment are important.
Recovery and rehabilitation depend on the area of the brain involved and the amount of tissue damaged. Harm to the right side of the brain may affect movement and sensation on the left side of the body. Damage to brain tissue on the left side may affect movement on the right side; this damage may also cause speech and language disorders. In addition, people who've had a stroke may have problems with breathing, swallowing, balancing and hearing, and loss of vision and bladder or bowel function.
Every person's stroke recovery is different. Depending on what complications you might have, the team of people to help you in your recovery could include:
• Rehabilitation doctor (physiatrist)
• Nurse
• Dietitian
• Physical therapist
• Occupational therapist
• Recreational therapist
• Speech therapist
• Social worker
• Psychologist or psychiatrist
• Chaplain
The goal of stroke rehabilitation is to help you recover as much of your independence and functioning as possible. Much of stroke rehabilitation involves relearning skills you may have lost, such as walking or communicating.

Prevention: 

Knowing your risk factors and adopting a healthy lifestyle are the best steps you can take to prevent a stroke. In general, a healthy lifestyle means that you:
• Control high blood pressure (hypertension). One of the most important things you can do to reduce your stroke risk is to keep your blood pressure under control. If you've had a stroke, lowering your 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 high blood pressure in check. In addition to recommendations for lifestyle changes, your doctor may prescribe medications to treat high blood pressure, such as diuretics, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers.
• Lower your cholesterol and saturated fat intake. Eating less cholesterol and fat, especially saturated fat, may reduce the plaques in your arteries. If you can't control your cholesterol through dietary changes alone, your doctor may prescribe a cholesterol-lowering medication.
• Don't smoke. Quitting smoking reduces your risk of stroke. Several years after quitting, a former smoker's risk of stroke is the same as that of a nonsmoker.
• Control diabetes. You can manage diabetes with diet, exercise, weight control and medication. Strict control of your blood sugar may reduce damage to your brain if you do have a stroke.
• Maintain a healthy weight. 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 your blood pressure and improve your cholesterol levels.
• Exercise regularly. Aerobic exercise reduces your risk of stroke in many ways. Exercise can lower your blood pressure, increase your level of high-density lipoprotein (HDL) cholesterol, and improve the overall health of your blood vessels and heart. It also helps you lose weight, control diabetes and reduce stress. Gradually work up to 30 minutes of activity — such as walking, jogging, swimming or bicycling — on most, if not all, days of the week.
• Manage stress. Stress can cause a temporary spike in your blood pressure — a risk factor for brain hemorrhage — or long-lasting hypertension. It can also increase your blood's tendency to clot, which may elevate your risk of ischemic stroke. Simplifying your life, exercising and using relaxation techniques are all approaches that you can learn to reduce stress.
• Drink alcohol in moderation, if at all. Alcohol can be both a risk factor and a preventive measure for stroke. Binge drinking and heavy alcohol consumption increase your risk of high blood pressure and of ischemic and hemorrhagic strokes. However, drinking small to moderate amounts of alcohol can increase your HDL cholesterol and decrease your blood's clotting tendency. Both factors can contribute to a reduced risk of ischemic stroke.
• Don't use illicit drugs. Many street drugs, such as cocaine and crack cocaine, are established risk factors for a TIA or a stroke.
Follow a healthy diet
In addition, eat healthy foods. A brain-healthy diet should include:
• Five or more daily servings of fruits and vegetables, which contain nutrients such as potassium, folate and antioxidants that may protect you against stroke.
• Foods rich in soluble fiber, such as oatmeal and beans.
• Foods rich in calcium, a mineral found to reduce stroke risk.
• Soy products, such as tempeh, miso, tofu and soy milk, which can reduce your low-density lipoprotein (LDL) cholesterol and raise your HDL cholesterol level.
• Foods rich in omega-3 fatty acids, including cold-water fish, such as salmon, mackerel and tuna.
Preventive medications
If you've had an ischemic stroke, your doctor may recommend medications to help reduce your risk of having a TIA or stroke. These include:
• Anti-platelet drugs. Platelets are cells in your blood that initiate clots. Anti-platelet drugs make your platelets less sticky and less likely to clot. The most frequently used anti-platelet medication is aspirin, taken daily. Your doctor can help you determine the right dose of aspirin for you.
Your doctor may also consider prescribing Aggrenox, a combination of low-dose aspirin and the anti-platelet drug dipyridamole, to reduce blood clotting. If aspirin doesn't prevent your TIA or stroke or if you can't take aspirin, your doctor may instead prescribe an anti-platelet drug such as clopidogrel (Plavix) or ticlopidine (Ticlid).
• Anticoagulants. These drugs include heparin and warfarin (Coumadin). They affect the clotting mechanism in a different manner than do anti-platelet medications. Heparin is fast acting and is used over the short term in the hospital. Slower acting warfarin is used over a longer term.
Warfarin is a powerful blood-thinning drug, so you'll need to take it exactly as directed and watch for side effects. Your doctor may prescribe these drugs if you have certain blood-clotting disorders; certain arterial abnormalities; or an abnormal heart rhythm, such as atrial fibrillation, or other heart problems.

Tags:

By Anonymous on 01 June 2011