Health Conditions

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Transient Ischemic Attack


Definition

A TIA is a brief interruption in the blood supply to the brain that leads to temporary neurologic deficits (weakness, numbness, tingling).

Description

Each year, over tens of thousands of Americans - most of them in their 60s and 70s - have at least one transient ischemic attack (TIA), a brief "mini-stroke" that temporarily reduces the blood supply to a specific area of the brain for less than 24 hours.

Symptoms are often so fleeting that they are easily dismissed. But TIAs are a serious warning sign for underlying cardiovascular disease that can lead to stroke. Within 5 years of having a TIA, about one-third of patients go on to develop a full-blown stroke, which may cause death or permanently impair vision, speech and movement. And a study published in the Journal Neurology early in 2003 reported that approximately 11 percent of people who are diagnosed with a TIA in the emergency room will have a stroke within the next 90 days.

Clearly, identifying and treating those with TIAs can reduce the risk of stroke and preserve the quality of life of thousands of people each year.

Causes

TIAs are usually caused by atherosclerosis (hardening of the arteries), due to buildup of cholesterol and other materials along the arterial walls. These materials form deposits called plaques, which narrow the artery and lead to the formation of blood clots that can cause complete blockage.

There are two types of clots that can cause complete blockage. These are thrombotic (which form in the arteries leading to the brain); and embolic (which form in the heart or other arteries and travel to the brain).

TIAs may occur when an artery serving the brain becomes so obstructed that an adequate amount of blood cannot pass through, or when a portion of the blockage breaks away from the arterial wall and travels to the brain. The episode resolves when the body restores blood flow by releasing enzymes that reopen the artery.

Those at highest risk are men and women over age 60. The incidence is high among African-American men, people with diabetes (even when it is well controlled) or high blood pressure, and those with a family history of TIA or stroke. Heart disease (including angina, congestive heart failure, rhythm disturbances, and valve disorders) is also a risk factor.

Symptoms

Symptoms - which are similar to those of stroke (and many other conditions) - may include one or more of the following: weakness, tingling, or numbness in the arms and legs on one or both sides of the body; vision and language problems; confusion; vertigo (the sense that either you or the room is spinning); poor balance; lack of coordination or headache.

Onset is sudden, and duration is usually brief. While a few episodes may last up to 24 hours, most pass within a few minutes, and nearly all resolve within an hour.

Of TIAs that persist for more than an hour, about 80 to 90 percent develop into full-blown strokes (which, by definition, last for more than 24 hours), and permanent disability is possible.

The natural history of attacks is variable. Some patients will have a major stroke after only a few TIAs, while others may have frequent attacks for weeks or months without having a stroke. Attacks may occur intermittently over many years, or they may stop spontaneously.

TIAs are extremely important predictors of stroke; don't ignore them! If symptoms appear, CALL 911 to get medical help immediately.

Diagnosis

Diagnosis is based on the medical history and the physical examination, which may be normal. An electrocardiogram (EKG), chest x-ray, head CT (computed tomography) scan and an ultrasound study of the carotid arteries (in the neck) may be performed. An echocardiogram (ultrasound study of the heart) or MRI may also be recommended.

Treatment

Lifestyle changes are standard, whether the blockage is caused by plaque or clots. This includes improved exercise and dietary habits.

A surgical option is often considered if the carotid artery is more than 70 percent narrowed. This procedure is called carotid endarterectomy. This removes plaque from inside the artery. An incision is made in the neck to expose the artery, and the damaged segment is cleaned out and sutured back together to restore normal blood flow. The risk of serious complications is about 5 percent.

Medical treatment may include antiplatelet medications (drugs that discourage plaque formation by preventing platelets from sticking together) and, when necessary, anti-hypertensive (lowering blood pressure) medications. Aspirin is by far the most commonly used antiplatelet drug. A newer drug called ticlopidine is an alternative for patients who are unable to take aspirin because of side effects, but requires close monitoring.

Additional treatments may be considered, depending on the source and location of the blockage. If clotting in the heart is a problem (because of rhythm disturbance, valve disease, or congestive heart failure), the "blood thinner" drug warfarin (Coumadin) is often used.

Prevention

One way to prevent TIAs is to adopt the same strategies that reduce the likelihood of stroke. By far the most effective measure is to keep blood pressure controlled, since high blood pressure promotes atherosclerosis. Even pre-hypertension (above 120/80 but not in the defined range for hypertension) increases risk of TIA and stroke. Recommendations include trying to:

  • Eliminate smoking. Smokers are two times more likely to have a stroke than nonsmokers.
  • Drink alcohol only in moderation. Heavy alcohol use also increases stroke risk, perhaps by increasing the viscosity of blood and making it more prone to clotting.
  • Exercise regularly and maintain a healthy weight on a healthy low-fat diet. These measures will help maintain proper weight and place less strain on the circulatory system. Losing as little as 10 pounds with diet and exercise may lower your blood pressure and improve your cholesterol levels.
  • Eat plenty of fruits and vegetables, which contain such nutrients as potassium, folic acid and antioxidants that may protect against a TIA or a stroke.
  • Control blood glucose. This improves general health and reduces diabetes-associated complications.
  • Limit sodium. Avoiding salty foods and not adding salt to food may reduce your blood pressure.
  • Control your diabetes if you have it.

Questions to Ask Your Doctor

  • How serious is a TIA?
  • Is there significant atherosclerosis?
  • Is there a risk of a stroke?
  • Will you prescribe an antihypertensive drug?
  • Should aspirin be taken?
  • What changes in lifestyle are necessary?
  • Is surgery necessary?

This article is the copyright of www.elitehealth.com

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Stroke


Definition

A stroke occurs when the arterial blood flow leading to or in the brain becomes blocked or a blood vessel in the brain ruptures. Blood carries oxygen and nutrients to the neurons (nerve cells) in the brain, so when the blood flow stops, the cells begin to die. As a result, the functions of the body controlled by the nerve cells can lose their ability to function.

Description

The specific abilities that will be lost or affected by the stroke depend on the extent of the cell death and where in the brain the stroke happened. The brain is divided into four primary parts: the right hemisphere, the left hemisphere, the cerebellum and the brain stem.

The right hemisphere controls:

  • Left side of the body.
  • Most analytical and perceptual tasks such as judging distance, size, speed, position.

The left hemisphere controls:

  • Right side of the body.
  • Speech and language.

The cerebelum controls:

  • Balance and coordination.

The brain stem controls:

  • Life-support functions such as breathing, blood pressure and heartbeat.
  • Eye movements.
  • Hearing.
  • Speech.
  • Swallowing.

Depending on the severity of the stroke, victims may or may not experience any or all losses of the above functions.

Causes

There are two broad categories of strokes, called ischemic stroke or hemorrhagic stroke. Ischemic stroke is caused by a blockage of a blood vessel in the brain or neck. About 80 percent of strokes are in this category. This stroke can stem from three different conditions: thrombosis, embolism or stenosis:

  • Thrombosis (cerebral thrombosis) is the formation of a clot within a blood vessel of the brain or neck and is usually caused by atherosclerosic plaque build-up.
  • Embolism (cerebral embolism) is the movement of a clot from another part of body to the brain or neck. These clots can form on artificial valves in the heart, on atherosclerotic plaques in aorta or caused from a condition called atrial fibrillation. Atrial fibrillation is an irregular heartbeat whereby the upper chamber of the heart quivers rapidly rather than beats. Because this quivering motion is not forceful enough to send all the blood to the heart's lower chambers, the blood pools, thus allowing clots to develop.
  • Aortic valve stenosis is a severe narrowing of an artery in or leading to the brain that results in substantially diminished blood flow.

Hemorrhagic stroke is the bleeding into the brain or the spaces surrounding the brain which is caused by a number of disorders that affect the blood vessels (i.e., high blood pressure and cerebral aneurysm). There are two types of hemorrhagic stroke: subarachnoid and intracerebral.

Subarachnoid hemorrhage is caused by the rupture of a blood vessel on the surface of the brain so that blood fills the space between the brain and the skull. An intracerebral hemorrhage is caused by the rupture of a blood vessel within the brain itself.

Some factors that increase the risk of stroke are genetically determined, others are simply a function of natural processes, and still others result from a person's lifestyle. The factors resulting from heredity or natural processes can't be changed, but those that are environmental can be modified with a doctor's help.

There are five unmodifiable risk factors:

  • Age - your chances of having a stroke go up as you get older. Two-thirds of all strokes happen to people over age 65. Your stroke risk doubles with each decade past age 55.
  • Sex - males have a slightly higher risk than females.
  • Race - American blacks have a higher stroke risk than most other racial groups.
  • Family history of diabetes.
  • Family history of stroke or TIA (transient ischemic attack).

There are two basic categories of risk factors that can be modified:

  • Treatable medical disorders - including: diabetes, atrial fibrillation, heart attack, high blood pressure, high cholesterol, carotid artery disease, heart disease, personal history of stroke or TIA and patent foramen ovale (PFO). PFO is an abnormal opening between the right and left sides of the heart.
  • Lifestyle factors - includes smoking, drinking too much, obesity, drug abuse (especially cocaine), physical inactivity and low estrogen.

Symptoms

The warning signs of stroke are:

  • Sudden weakness or numbness of the face, arm and leg on one side of the body.
  • Loss of speech, or trouble talking or understanding speech.
  • Dimness or loss of vision, particularly in only one eye.
  • Unexplained dizziness, unsteadiness or sudden falls.
    "Temporary strokes" (transient ischemic attacks or TIAs). These can occur days, weeks or even months before a major stroke. TIAs result when a blood clot temporarily clogs an artery and part of the brain does not get the supply of blood it needs. The symptoms occur rapidly and last a relatively short period of time, usually from a few minutes to several hours.

Treatment

Treating a stroke depends on where the stroke occurred in your brain and whether it's ischemic or hemorrhagic. The doctor may use a Magnetic Resonance Imaging (MRI) scan, computed tomography (CT) imaging or angiography (injecting dye through a catheter inserted into the suspected blocked blood vessel and taking x-rays of the vessels) to determine the stroke type and location.

Time is critical. Until a few years ago, strokes were regarded as untreatable. Brain cells were thought to die within minutes after a stroke began, so stroke treatment was believed useless. The only onsite medical treatment is stabilization and "wait and see." Now researchers have discovered that some brain cells die immediately after a stroke, but others can survive for as long as several days. It is now clear that treatment following a stroke, especially if begun within three hours of onset, can help preserve brain tissue.

Since 1996, FDA approved tissue plasminogen activator (TPA) is the the first treatment for strokes caused by arterial blockages. This "clotbuster" is inserted into the femoral artery near the groin and then threaded up into the brain to directly dissolve the blood clot, thereby limiting or stopping the damage to the brain cells. This therapy is used on ischemic strokes and only effective within three hours of onset.

The use of t-PA is not recommended after three hours of onset due to the risk of hemorrhaging, thus standard treatment is administered. In an ischemic stroke the goal is to (1) maintain normal blood pressure and (2) improve blood flow by preventing recurrent clots. This is done by administrating anti-hypertensives to reduce blood pressure, platelet-inhibiting drugs such as aspirin, ticlopidine (Ticlid) or an anticoagulant such as heparin, coumadin or warfarin to prevent blood clots from forming or growing.

If unsuccessful, a carotid endarterectomy may be considered. This procedure removes the atherosclerotic plaque and the blood clot from the left or right carotid artery (the major vessels that carry blood through the neck to the brain) thus allowing the blood to flow uninterrupted.

In a hemorrhagic stroke, the goal is to (1) get the blood pressure under control and (2) correct the cause of the hemorrhage and protect the brain from further damage. The hemorrhage causes blood to pool in the brain and thus increases pressure on the brain. The doctor will give diuretic drugs to minimize the temporary swelling of the brain tissue.

Rarely is surgery recommended, but if tests detect an aneurysm, the surgeon may clamp the aneurysm at its base and then remove it. The surgeon now has the option to use a catheter, containing a metal coil, that passes through the blood vessel in the neck. The metal coil causes the aneurysm to clot and seal itself off.

Medications may be recommended to help reduce the risk of having another TIA or stroke. Some of these medications include antiplatelet drugs (aspirin, clopidogrel or ticlopidine) drugs and anticoagulants (heparin and warfarin).

Some people are only slightly affected by strokes. Others recover quickly from what seemed like a severe stroke. Still others may suffer such serious damage that it will take a long time to regain even partial use of their limbs, speech, or whatever faculties that have been affected.

Successful rehabilitation depends on the extent of brain damage, the patient's attitude, the skill of the rehabilitation team, and the cooperation of family and friends. Most stroke patients can benefit from rehabilitation, and today the outlook for stroke patients is more hopeful than ever before. Because of advances in treatment and rehabilitation, many patients are being restored to a fully functional life.

For rehabilitation to be most effective, three points must be kept in mind:
Rehabilitation must begin as soon after the stroke as possible.
The family can be the patient's most important means of support during the rehabilitation process.
Rehabilitation is a team effort with the physician, nurse, and other specialists working with the patient and their family.

Prevention

Strokes may be prevented by lowering your blood pressure, quitting smoking, beginning or increasing exercise, controlling medical problems with medications, maintaining optimal weight through appropriate physical activity and dietary behaviors, and eating a diet high in fruits and vegetables.

If you have a blocked carotid artery your doctor may suggest a carotid endarterectomy to remove the fatty deposits.

Questions to Ask Your Doctor

  • What are the chances the symptoms were caused by something other than a stroke?
  • What was the cause of the stroke?
  • What tests are used to determine what type of stroke occurred and how much damage was done?
  • What medications will be prescribed? What are the side effects?
  • Would surgery be recommended to improve cerebral circulation? If so, what type of surgery?
  • What other treatment can be used to prevent another stroke?
  • Is there a support group for the family to go to ask questions?
  • What are the chances of having a stroke after a TIA or having another stroke after a first?
  • What do we need to know about rehabilitation?
  • Can the rehabilitation be done on an outpatient basis?
  • Will a nurse or therapist help instruct us on what we need to know for home care such as exercise, diet and communication?
  • Approximately how long will rehabilitation take to return to normal activities?

This article is the copyright of www.elitehealth.com

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