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STROKE

A stroke is defined as a sudden loss of brain function due to a blocked or burst blood vessel. There are two classifications of stroke, ischemic and hemorrhagic. Ischemic strokes account for approximately 80 percent of all strokes and result from blockage of the blood supply to the brain. Hemorrhagic strokes account for the remaining 20 percent of all strokes and result from bleeding in the brain. When the bleeding is in the brain itself, it is an intracerebral hemorrhage; if the bleeding occurs between the brain and the skull, it is a subarachnoid hemorrhage.

The brain needs a continuous and fresh supply of oxygen and glucose to function. Oxygen and glucose are carried in the blood and reach the brain through four arteries arranged in two systems. The carotid arteries in the neck carry most of the blood to the brain. The vertebral arteries in the spine join at the base of the brain to form the basilar artery. They supply blood to the core of the brain, which deals with vital functions. Any interruption of blood supply to the brain interferes with the brain’s ability to function.

Causes of ischemic stroke

Ischemic stroke occurs when the blood supply to the brain is blocked. The most common cause of blockage is blood clots. Blood clots can form almost anywhere in the body, dislodge, and travel through the arteries eventually lodging and diminishing or cutting off blood flow. They originate most commonly in the heart. Blood clots form in the heart for many reasons, including birth defects, malfunctioning or damaged heart valves, and an irregular heartbeat (atrial fibrillation).

Damaged arteries represent another leading cause of ischemic stroke. There are three main causes of damage to the arteries. Atherosclerosis can occur in any artery in the body but causes stroke most often when it is found in the neck arteries. As people age, small streaks of fat settle in the walls of the arteries. These streaks can grow into plaque that can trap cells in the blood platelets that start clotting. The fatty deposits build up and can eventually fester and crack, forming clots that either close off a neck artery or wash up into the brain, resulting in a stroke.

Accidental damage to the neck arteries can also cause stroke. An artery has three layers, and any sudden twist of the neck or direct trauma to the neck can cause the arterial layers to shear apart (dissection) and either close the vessel or create clots that will cause blockage that results in stroke.

In people who suffer from high blood pressure, their brain blood vessels can become thick, stiff, and brittle. Because there is less room for blood to flow and the vessels are not flexible enough to accommodate increased blood pressure, they can either close off completely or rupture. Diabetes can also weaken the small blood vessels of the brain.

Blood abnormalities can be a potential source of stroke. Abnormalities in the blood can cause clotting, bleeding, or both.

Blood supply is essential to the health and operation of the brain. The areas of the brain that do not receive enough blood or no blood at all will die, resulting in dead tissue (infarct) and loss of brain function.

Causes of hemorrhagic stroke

Hemorrhagic stroke occurs when there is bleeding within the brain. It is less common than ischemic stroke but is often more severe.

There are three main causes for bleeding in the brain (intracerebral hemorrhages). High blood pressure can weaken the arteries so that they eventually rupture and cause bleeding. Blood can become too thin as a result of blood thinning medication (anticoagulants). And as people age, they tend to have abnormal deposits of amyloid protein (amyloid angiopathy) in blood vessels, which can lead to bleeding in the brain.

Bleeding around the brain, known as subarachnoid hemorrhage, most often results from a burst aneurysm. An aneurysm develops on a weakened part of a blood vessel and resembles a pouch. A bursting aneurysm is usually signaled by a sudden, unusual, and severe headache. Some have suggested that it feels like being struck on the back of the head by a baseball bat. Other symptoms associated with a burst aneurysm may include neck stiffness and double vision. Not all aneurysms are dangerous or require surgery, but if an aneurysm ruptures it is quite serious.

The second most common cause of subarachnoid hemorrhages is the rupture of a cluster of abnormal blood vessels in the brain, the arteriovenous malformation.

Areas of the brain and effects of damage

The brainstem is considered to be an extension of the spinal cord and is nestled below the larger part of the brain. It is responsible for critical automatic functions of the body, such as breathing, maintaining blood pressure and heart rate, swallowing, chewing, eye movements, and quick reflexes. It is also the site of major passageways to and from the upper brain and the rest of the body. A stroke that originates in the brain-stem is usually fatal. Fortunately, many strokes involve only part of the brainstem. Double vision, imbalance, trouble swallowing, and weakness or numbness of the face or limbs may result, depending on the part of the brain stem that is affected.

At the back of the brainstem is the ‘‘little brain’’ or cerebellum. The cerebellum coordinates movements and balance, and stores the memory of habitual muscle movements, such as the pattern of the muscle movement used to swing a baseball bat. A stroke that hits the cerebellum can cause unsteadiness, lack of coordination, and awkwardness of the limbs.

Some consider the cerebrum to be the most important part of the brain. It is the most highly developed area of the brain and is what defines people as humans. The cerebrum receives information from all parts of the body, processes the information, and reacts almost instantaneously. A stroke in the cerebrum can affect so many aspects of day-to-day living. To better understand how a stroke survivor can be affected, one should look at all of the parts of the cerebrum.

The cerebrum is divided into two hemispheres, right and left, each controlling the side of the body opposite to it. Each hemisphere controls certain functions, but the two are connected by nerve fibers that allow them to work together or compensate for one another.

The right hemisphere recognizes shapes, angles, proportions, and visual patterns such as people’s faces. The right hemisphere is responsible for emotions, musicality, creativity, and imagination. It also controls a person’s spatial self-awareness. For example, some people who have had their right hemisphere damaged by a stroke no longer feel that their body is their own, and some who are paralyzed on the left side of their body may not recognize their own left hand.

The left hemisphere controls speech, logic, analytical thought, problem solving, language, and movements on the right side of the body. Stroke in the left hemisphere may result in paralysis of the right side of the body and difficulty with communicating and understanding.

The hemispheres are further divided into four lobes. The occipital lobe is the vision center, and a person can be left blind even if the eyes are not damaged when the stroke hits here.

The temporal lobe forms and stores memories, and unless both the right and left temporal lobes are affected, memory loss is not likely to be permanent. Hearing and understanding speech are other functions of the temporal lobe. Wernicke’s area spreads from the temporal lobe into the neighboring parietal lobe, and a stroke here impairs ability to understand language but almost never affects hearing.

The parietal lobes influence the sense of space, perspective, and interpretation. They also contain a strip of sensory cortex that receives and interprets information from the body. The motor cortex is located in front of the sensory cortex, and if it is damaged, paralysis of the face, arm, or leg can occur.

Behavior, anticipation, emotion, thinking, motor function, planning, and speech expression are controlled in the most highly developed part of the brain, the frontal lobes. The frontal lobes influence much of what is considered to be an individual’s personality, and as a result the ability to test the damage to frontal lobes and the degree of impairment is difficult. Stroke can change personality and thinking. A patient may appear to act out of character and the ability to determine what is socially appropriate and what is not may be impaired. Increased difficulty with completing tasks can also be seen. This can be a result of the patient’s forgetting sequences of steps to finish something or inability to send the message to the appropriate muscles to complete a task.

The human brain is a very complicated organ, and stroke damage can be devastating. However, the prognosis is not always so bleak. The brain’s ability to have other parts of it assume lost function and its ability to adapt are just being discovered, bringing greater hopes of recovery for the future.

Warning symptoms

Typically, many think of stroke as a disease affecting only elderly persons, particularly men. This is not the case at all. Stoke can strike an individual of any age, race, or gender. As people age, the risk for stroke increases, but the warning signs of stroke are something that everyone should know.

A person who suddenly experiences one or more of the following symptoms may be having a stroke: (1) weakness or numbness of the face, arm, or leg; (2) loss or slurring of speech; (3) loss or blurring of vision; (4) a sensation of motion (vertigo); (5) difficulty with balance; (6) unusual or severe headache. The sudden onset of any one or more of these symptoms requires immediate action. Stroke is a medical emergency and must be treated accordingly. The sooner medical help is obtained the better the chances for surviving a stroke.

Symptoms of stroke usually occur within seconds. If the symptoms come on quickly and disappear just as quickly, a doctor should be contacted. If the symptoms still persist after fifteen minutes, the person should be taken to the emergency department of the nearest hospital where a specialist can assess the symptoms.

Symptoms of migraine headaches can sometimes be confused with symptoms of stroke. The key difference in the onset of symptoms lies in the timing. Migraine symptoms usually progress over minutes, whereas stroke symptoms occur in mere seconds. Timing is a critical factor in assessing stroke.

Transient ischemic attacks, more commonly known as TIAs, are a crucial warning sign of an impending stroke. The symptoms of a TIA are exactly the same as of a stroke; the only difference is that the symptoms usually disappear within fifteen minutes. Just because a symptom goes away does not mean that the person is not at risk. TIAs can indicate that the brain is having difficulty receiving the required amount of blood and the person is therefore more likely to have a stroke. Immediate diagnosis of symptoms can drastically reduce the chance of a stroke. Having a TIA does not mean a person will definitely have a stroke, but it is a key indicator that medical attention is needed.

Heart attack can be associated with stroke. The term ‘‘brain attack’’ was invented to advise people that the stroke is serious and that urgent medical attention is required. The most common cause of heart attack is also the most common cause of stroke. Hardening of the arteries (atherosclerosis) impedes blood flow and can create blood clots, leading to either heart attack or stroke. People who suffer a stroke may also suffer a heart attack, and vice versa. One reason for this may be that people who have either a stroke or a heart attack, have common risk factors for atherosclerosis, such as family history, high blood pressure, smoking, diabetes, high cholesterol, or homocystenemia.

There are three major differences between heart attack and stroke. First, there are many more causes of stroke than of heart attack. Second, heart attack is more easily diagnosed by either an electrocardiogram or a cardiac enzyme test, whereas images of the brain may not show any changes in the brain until hours after the onset of stroke symptoms. As a result, the diagnosis of stroke relies heavily on clinical judgment.

Last, chest pains (angina) are a clear indication of an impending heart attack. The greater the chest pain, the greater the problem. This is not the case with stroke. Whether a person has one TIA or several, the risk of stroke is the same. Preexisting conditions and risk factors contribute more to the chance of stroke than does how often TIAs occur.

Some other medical conditions can mimic stroke; for instance, the shearing of the artery within the skull or a brain tumor can create symptoms that may at first appear to be those of a stroke. Clinical diagnosis by a physician is the only way to determine if a person has had a stroke.

Diagnosis

As more knowledge is gained about the brain, the prognosis for stroke survivors becomes better. The clinical diagnosis of stroke is an essential part of the treatment process. When a patient arrives at the hospital, the first thing the doctor will do is assess his or her condition. A primary care doctor may be the first doctor one sees, but once a problem with the brain or nervous system is identified a specialist will be called. Neurologists are specialists who diagnose and treat conditions of the brain, but they do not perform surgery. Neurosurgeons perform surgery on the brain and other parts of the nervous system. Other medical specialists may be consulted if the problem involves their area of expertise.

After taking a verbal history, the physician conducts a physical exam. The physician may begin by evaluating muscle strength, reflexes, coordination, balance, capacity to hear, see, smell, and feel, and ability to speak. On the basis of physician’s findings, other diagnostic tests may be ordered.

An image of the brain is important in diagnosing a stroke. The physician is looking to see if there is blood on the brain, and if so, where it is. The physician is also trying to see if there is dead tissue (infarct) in the brain, and, if there is, to confirm that this is the result of a stroke (and not something that mimics stroke). Two main ways to get an image of the brain are computerized tomography scan (CT scan) and magnetic resonance imaging (MRI). During the CT scan, a painless procedure, the patient’s head is placed in a device that looks like a big salon hair dryer. The patient simply lies back and relaxes while X-rays are beamed to reveal the structure of the brain. The MRI may look more intimidating than the CT scan because the patient is put on a bed in a large machine, but it too, is a painless procedure. MRI uses radio frequencies to image the brain and the blood vessels in the head and in the neck. Because technology for the MRI is increasing at a rapid rate, and it is providing more information, it is becoming the diagnostic method of choice.

Ultrasonography has two uses: (1) to measure the speed of blood flow, which helps to determine where there are blockages in arteries; and (2) to produce an image of the blood vessel. The carotid Doppler test is done by moving a device up and down the neck to see if there is a narrowing of the arteries, and a transcranial Doppler test is an ultrasound technique that gives information about the blood flow in the main arteries of the brain.

Imaging of the brain can usually detect the presence of blood, but in some circumstances a spinal puncture, or spinal tap, will be performed to rule out the possibility. The procedure involves taking a small needle, inserting it between the vertebrae in the back, and taking a sample of cerebrospinal fluid to analyze.

Echocardiograms and electrocardiograms are the two types of tests used to detect any abnormalities in the heart that could have caused a stroke. In an echocardiogram, ultrasound creates an image of the heart from which the doctor can see if any blood clots are in pockets of the heart and if the valves of the heart are normal or abnormal. The electrocardiogram maps the heartbeat, making it possible to detect irregular heartbeats, insufficient blood supply, and damaged parts of the heart. Analyzing the heart is important because the heart can be a source for blood clots that break away and reach the brain.

Blood tests are generally done to identify problems that could complicate stroke. Depending on the patient’s medical history, liver and kidney tests may also be done to detect damage. All of these tests and procedures play a part in the physician’s diagnosis.

Treating acute stroke

Stroke patients can be treated in many different settings, but the ideal place for treatment is a stroke unit, where the doctors, nurses, and therapists work together as a specialized unit. When a stroke patient arrives at the hospital, overall medical treatment includes maintaining blood pressure, reducing elevated temperature, and normalizing blood glucose levels. Specific measures performed by the stroke team include attempting to reopen closed blood vessels, protecting the brain, and preventing complications.

Maintaining blood pressure of the patient is important because after stroke, the brain may be unable to control its own blood supply (autoregulation). Blood supply depends on blood pressure, and if the blood pressure is not high enough to pump blood to the damaged area, brain cells will die. To prevent further damage to the brain after stroke, the medical team makes sure that blood pressure is maintained by measuring and medicating if necessary.

Temperature is another factor when treating a stroke patient. An increase in body temperature of even one degree centigrade will double the risk of death or disability in a stroke patient. In addition, patients with a high level of blood glucose at the time of a stroke are less likely to recover; therefore, reducing blood glucose in the acute situation benefits the patient.

The most common cause of stroke is the closing off of a blood vessel to the brain. Some studies have shown that giving the patient a clot-busting (thrombolytic) drug may reopen the closed blood vessels to the head. Thrombolytic drugs are effective only if given early in the onset of stroke and also carry a great risk of causing more bleeding to the head, thus causing more damage and possibly death. The drug in this classification that has been receiving much attention is tissue plasminogen activator (t-PA). It has been used with success in the treatment of heart attacks and is currently being used in treating stroke. The side effect of bleeding to the head may result in death, so it is important that thrombolytic drugs be researched and tested in centers where there are experts in stroke and facilities to deal with the possible consequence of bleeding into the head. With time and caution, thrombolytic treatment may play a more important role in the treatment of acute stroke.

Another type of drug works to protect the brain after stroke. In laboratory studies these drugs have protected the brain when blood deprivation occurred. They are now being tested in clinical studies.

Brain cell repair is the future of recovery after stroke. More is being learned about how the brain repairs injury and the potential of injecting engineered cells to help healing. It may be the case that a combination of drugs that open the blood vessels to the brain protect the brain from breakdown, and speed up the repair of the brain will be the ideal treatment of the future.

Surgery is not used in the acute treatment phase unless a blood clot is pressing on one of the vital parts of the brain or if an aneurysm has ruptured and there is bleeding around the brain (subarachnoid hemorrhage). Timing is important when dealing with a ruptured aneurysm. There are two approaches considered by the neurosurgeon: (1) to operate before the brain vessels go into spasm (vasospasm), or (2) to wait a for the vasospasm to disappear and then operate. Operating early has a higher rate of complication, but waiting allows vasospasm to cause further damage. Thus, early surgery is often chosen despite the overall risk.

Aneurysms that have been found by diagnostic testing and have not bled, do not necessarily require surgery. If the aneurysm is less than 10 mm in diameter, the patient usually will be monitored. If the aneurysm measures greater than 10 mm in diameter, surgery or treatment with balloons or coils delivered through a tube (catheter) in the blood vessel may be considered.

Preventing complications is a main concern of the stroke team. When a patient is bedridden for a long period of time, blood becomes stagnant and tends to pool, which may make the patient more prone to developing blood clots, resulting in further damage and even death. Lying in the same position for a long time can also cause painful bedsores and the shortening of muscles (contractures). Initially, the stroke team will move an immobilized patient and perform range of motion exercises to keep muscles limber. As the patient gains ability, he or she can take over some of these exercises to help prevent complications. Stroke patients are also at higher risk for infection, and are carefully monitored by the doctor and nurses to ensure that they remain as healthy as possible.

In the first few hours after a stroke, it can become fairly clear what the prognosis for the patient will be. In some cases the result of stroke can be more grievous than death, and the family will be told what they can expect. At a time when emotions are so highly charged, it may be difficult to make a decision that is best for the patient, especially if the patient is unable to communicate his or wishes. Situations like this can be avoided by having a living will or an advance health care directive in place. This document is prepared beforehand for emergency situations and lets the doctors and family know what the patient would like done in certain situations if he or she is unable to communicate. For example, an incapacitated patient who goes into cardiac arrest may not wish to be revived. This is something that can be established legally before a catastrophic event. Advance health care directives may have different names and different regulations governing them in the states and provinces. Having an advance health care directive in place makes the person’s wishes clear and removes the burden of not knowing what to do from the family.

Rehabilitation

Rehabilitation begins as soon as possible after stroke, and recovery involves several different health disciplines. Along with the stroke survivor and his or her family and friends, the recovery team can include the physician, nurses, physiotherapist, occupational therapist, speech therapist, dietitian, social worker, and psychologist.

Not knowing the effects of a stroke is one of the most frightening aspects when beginning rehabilitation. The stroke survivor is faced with the prospect of not only lasting physical disability, but also lasting mental disability. The extent of damage that the stroke survivor must overcome depends largely on the type of stroke experienced and where the stroke damaged the brain. The rehabilitation team is there to support the patient and the family in recovering lost ability and learning to accept what cannot be changed.

The rehabilitation team’s first task begins as soon as the patient’s health has stabilized. The main goals are to prevent a second stroke and avoid any complications that may delay recovery. Keeping the patient as mobile as possible helps to prevent blood clots from forming and any stiffening of the joints.

Common effects on muscles and movement of the patient include weakness, paralysis, spasticity, loss of sensation, and loss of bladder and bowel control. Most patients suffer from some sort of muscle weakness after stroke, either because the muscle has been directly affected or because the muscle is atrophying from lack of use. Paralysis is another common effect and tends to involve one side of the body. If the arm and the leg on the same side of the body are affected, it is referred to as hemiplegia. Rehabilitation concentrates on maximum recovery of use of the paralyzed limbs, but if recovery is limited or not possible, the rehabilitation team teaches the patient techniques to compensate.

Spasticity occurs when the brain loses control over the contraction of a muscle and the muscle contracts involuntarily. It is a common physical response to any injury to the brain. The muscle does not, and cannot, obey the brain’s signals to relax, and remains stiff, taut, and painful. Spasticity sometimes is reduced but more often than not it remains. Physiotherapists help move the affected limbs through range of motion exercises to stretch the muscle, and casts, splints, or local anesthesia may be used as temporary measures. Any medication to treat spasticity must be used with caution, so as not to interfere with any medication being taken to control the stroke. Only in rare, severe cases is surgery performed.

Damage to one side of the brain can cause the patient to lose sensation in the opposite side of the body. For instance, some patients scalded themselves with water because they could not feel its temperature. The rehabilitation team can help set up the stroke survivor’s home with basic safety features to avoid such mishaps.

Difficulty with bladder and bowel control happens to some stroke patients. The most common problem is frequency. The patients must empty their bladder more often and cannot avoid wetting accidents if a toilet cannot be found quickly. Bowel incontinence is not as common and both conditions can be helped by the use of medication and adult diapers.

Speech problems are common in stroke survivors. This can be one of the hardest aspects of stroke recovery because many people associate mental incompetence with speech disorders. Speech disorders are a result of the brain being unable to function properly rather than a reflection of mental competence.

There are two basic categories of speech disability: aphasia and dysarthria. Aphasia, a disorder of language, can be divided into two main categories: expressive, or Brace’s aphasia (the most common form of aphasia) is the term used when a patient cannot express thoughts verbally or in writing. Frustration is common in patients with aphasia because they understand what people say to them and they know how they want to respond but are unable to find and say the proper words. Receptive, or Wernicke’s aphasia, occurs when the patient cannot understand spoken or written language.

Dysarthria is a speech disorder that causes the patient to slur words or make the pronunciation hard to understand. Pitch of the voice and ability to control the volume of voice may also be affected. As soon as possible, a speech therapist will involve the patient in a series of exercises to try to recover any lost function of the brain. Over time, aphasia and dysarthria can sometimes be partially reversed.

Helping the patient to adapt is a key function of the rehabilitation team. They can teach the patient and the family new methods for coping and techniques that will make routine tasks easier. Practicing routines with the patient also plays a part, particularly when the patient is having difficulty thinking. It is common for the stroke survivor to suffer from a decreased attention span, lack of concentration, limited memory, or decreased ability to make a decision or solve a problem. The rehabilitation team can provide simple, step-by-step instructions and practice a routine with a patient who is having difficulty remembering how to start a task or difficulty processing the steps required to finish it. Accepting that it may take longer to think, make decisions, or complete tasks can help reduce the frustration that the patient feels.

Stroke often makes a formerly independent individual dependent on others for even the most basic tasks. This can leave the individual with feelings of anger, inadequacy, unworthiness, and discouragement. As a result, clinical depression is a very common aftereffect of stroke, not only for the stroke survivor but for the care-giver as well. Depression is a natural reaction to any loss, and the rehabilitation team can help the stroke survivor and the family come to terms with the loss by offering methods for coping, contact with support groups, and, in some cases, medication.

A patient who is depressed after a stroke also commonly suffers from emotional lability, the dramatic swing of emotions from tears to laughter and back. This swing is uncontrollable and may appear to happen for no reason at all. Fortunately these responses tend to occur less often over time.

When the brain is injured as a result of stroke, personality and behavior may change. A stroke survivor who previously was always cheerful and helpful, may now be surly and despondent. Emotional and behavioral responses to stroke are often interlinked. The stroke survivor may have damage in a part of the frontal lobe that is causing him or her to act in such a manner, and may also be reacting emotionally to a sudden and devastating situation. A physician’s diagnosis and the rehabilitation team’s support will help the patient and their family find ways to cope with all of the changes.

There is no set timeline for the recovery of stroke survivors; however, neurological recovery tends to peak within the first few months after a stroke and then lessen. The physical recovery tends to be slower than the neurological recovery but usually continues for a longer period of time. Ultimately, the earlier recovery begins the better the prognosis, though individual determination and a strong support system have proven to be big factors in the recovery of stroke survivors.

Risk factors

There are many factors to consider when assessing risk for stroke. Some risk factors are nontreatable and some are treatable, and there are other factors that protect against stroke. The first step is to have a medical assessment of risk. If risk factors are managed and protective, and factors are enhanced in accordance with medical advice, then chances of having a stroke will decrease.

Nontreatable risk factors include age, gender, family history, and ethnicity. In general, the greater the age the greater the risk for stroke; however, it is important to note that someone young or seemingly healthy may still be at risk for stroke. Stroke has been documented as early as when a child is still in the womb. Such cases are less common, but the important point is that it is never too soon to be aware of risk factors for stroke.

Traditionally stroke has been associated with men. This is not the case at all. From the ages forty-five to seventy-five, men tend to have more strokes than women, but from ages fifty-five to eighty-five, women assume similar risks to men. While initially the number of strokes for men may be slightly higher than for women, the effects on women tend to be more devastating. Many more men recover from stroke than do women. Heart attack and stroke account for more deaths in women than any other disease. The notion that stroke is gender-specific is a dangerous one. Both sexes need to be aware of risk factors for stroke.

Hypertension, diabetes, and a history of heart disease are three main factors considered when taking a family medical history. Hypertension and diabetes are often inherited, and are both risk factors; heart disease may suggest a tendency to have hardening of the arteries (atherosclerosis). While individuals cannot escape their family history, they can use it to their advantage by making their doctor aware of conditions in their family that put them at risk for stroke.

Similarly, ethnicity cannot be controlled. Studies have shown stroke to be an important concern for Asian and African-American populations, whose risk for stroke is slightly higher than for Caucasians.

With medical advice, the following treatable risk factors can be managed and the chance for stroke reduced.

High blood pressure makes the muscular wall of blood vessels thicker. When the walls cannot thicken any more to accommodate the increasing blood pressure, they become brittle. This can result in the blood vessel closing off or rupturing, thus causing bleeding in the brain.

Smoking is a risk factor for all types of stroke as well as for heart disease. It directly damages the lining of the arteries. Smoking breaks down the elastin that gives the blood vessels flexibility. For a person who smokes, the risk of sudden death from heart attack doubles.

Homocystenemia leads to hardening of the arteries and increased clotting of the blood. High levels of the natural chemical homocysteine in the blood can be treated with vitamin B-6, vitamin B-12, and folate.

High cholesterol builds up deposits in the lining of the blood vessels, making it more difficult for blood to flow through and increasing the chances of a blockage resulting in stroke.

Diabetes damages the lining of blood vessels, which can lead to stroke.

Weight is an indirect risk factor for stroke. In general, a healthy body weight improves overall health and reduces the potential risk for disorders, such as high blood pressure, high cholesterol, and diabetes that may lead to stroke.

Heart disease can lead to clots forming on damaged areas of the heart and then finding their way to the brain, resulting in stroke.

Prior strokes increase the risk for later strokes. The medical history may indicate that a continued risk for stroke, but with medical attention the risk may be reduced.

TIAs are the body’s way of warning that a person is at risk for stroke. Those affected should seek medical attention immediately.

Chiropractic treatment involving vigorous twisting of the neck can shear the lining of the arteries in the brain, potentially leading to stroke. Individuals who are at risk for stroke may want to consider the type of treatment they receive.

Oral contraceptives used to contain a higher dose of estrogen, which could increase the chance of stroke. Low-estrogen contraceptives do not put women at risk for stroke unless they also smoke; in that case, the combination increases the chances for stroke.

Medications in rare cases, have been linked to heart valve damage, high blood pressure, seizures, heart attack, stroke, and death. Using medication only when necessary and following instructions, are important because misuse of a ‘‘safe’’ medication can increase the risk of stroke.

Substance abuse can cause stroke. Cocaine increases blood pressure dramatically and if the individual has weakened blood vessels, a major stroke will follow. Heroin inflames the blood vessels, thus increasing the risk for stroke. Contaminated needles are also a concern because they can cause an infection in the heart valves that will produce clots that go to the brain.

Migraine headaches do not necessarily warn of a stroke, but it has been documented that people who suffer from migraine with visual symptoms (classical migraine) are at a slightly higher risk for stroke. The combination of migraine headaches and either smoking or taking birth control pills can also increase the risk for stroke.

Stress is unavoidable for most people, but the degree of stress and how an individual handles stress are important factors in controlling the risk for stroke. Studies have indicated that stress and the way it is handled is an indirect factor for stroke based on elevated blood pressure and progression of atherosclerosis.

Enhancing protective factors can also reduce the risk for stroke. These factors include diet, exercise, estrogen, and aspirin. A doctor will be able to give more individualized information. Not every patient will benefit by taking aspirin as a preventive measure, nor will all women require estrogen replacement therapy.

A healthy diet, reducing alcohol consumption, and a moderate exercise plan are good ideas for prevention of many medical diseases, including stroke and heart disease. Again, it is a good idea to meet with a medical professional before making major changes so that the patient can be advised how to proceed and what to be aware of.

Prevention

The best way to prevent stroke or reduce the chances for stroke is to manage the risk factors listed above. In more serious cases, a physician may prescribe medication or recommend surgery.

The two main factors that lead to stroke are disease in the large and small arteries (atherosclerosis) and heart disease. In these conditions, clots can form and travel to the brain. Two main types of medication are prescribed for treatment: antiplatelet drugs and anticoagulant drugs. Antiplatelet drugs prevent clots by preventing the clumping of blood cells. These drugs include aspirin, ticlopidine, Clopidogrel, and dipyridamole. They prevent clots by thinning the blood, and include warfarin and coumadin.

Under the right circumstances, surgery can be used to considerably reduce the chance of stroke in an individual. The most common and most successful procedure is a carotid endarterectomy, first performed in the 1950s. If a patient has been found to have a narrowing in the carotid artery (the artery that takes blood to the brain), then surgery may be required to remove the narrowing. Surgery is not beneficial or even necessary in every case, so it is best to consult a specialist.

Perhaps the biggest part of prevention is knowledge, including learning the warning signs for stroke, having an annual check-up, and being aware of risk factors that can be controlled; educating oneself but not diagnosing oneself (instead consulting a professional) if unsure; and, making sure that information comes from a reliable source. It is best to rely on stroke information from national organizations because the main purpose of television is to entertain (e.g., certain information may be sensationalized), and information on the Internet can come from anyone.

VLADIMIR HACHINSKI LARISSA HACHINSKI

See also CHOLESTEROL; DIABETES MELLITUS; EPILEPSY; HEART DISEASE; HIGH BLOOD PRESSURE; LANGUAGE DISORDERS; PRESSURE ULCERS; REHABILITATION; VASCULAR DEMENTIA.

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