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.

BIBLIOGRAPHY

Adair E. S., and Pfalzgraf, B. Pathways: Moving beyond Stroke and Aphasia. Detroit, Mich: Wayne State University Press, 1990.

Ahn, J., and Ferguson, G. Recovering from Stroke. York: HarperCollins, 1992.

American Heart Association. The American Heart Association Family Guide to Stroke Treatment, Recovery and Prevention. New York: Times Books, 1994.

Ancowitz, A. The Stroke Book. New York: William Morrow & Company, 1993.

Bergquist, W. H.; McClean, R.; and Kobylinski, B. A. Stroke Survivors. San Francisco: Jossey-Bass, 1994.

Donahue, P. J. How to Prevent a Stroke: A Complete Risk-Reduction Program. Emmaus, Penn: Rodale Press, 1989.

Foley, C., and Pizer, H. F. The Stroke Fact Book. New York: Bantam Books, 1985.

Gordon, N. F. Stroke: Your Complete Exercise Guide. Champaign, Ill: Human Kinetics Publishers, 1993.

Heart and Stroke Foundation of Canada. The Canadian Family Guide to Stroke Prevention, Treatment and Recovery. Toronto, Ontario: Random House of Canada, 1996.

Josephs, A. The Invaluable Guide to Life After Stroke: An Owner’s Manual. Long Beach, Calif.: Amadeus Press, 1992.

Klein, B. S. Slow Dance, A Story of Stroke, Love and Disability. Toronto, Ontario: Knopf Canada, 1997.

Larkin, M. When Someone You Love Has a Stroke. A National Stroke Association Book. New York: Dell Publishing, 1995.

McCrum, R. My Year Off. Toronto, Ontario: Knopf Canada, 1998. National Stroke Association. Living at Home after Your Stroke. Englewood, Col.: National Stroke Association, 1994.

Newborn, B. Return to Ithaca. Rockport, Mass.: Element Books Limited, 1997.

Senelick, R. C.; Rossi, P. W.; and Dougherty, K. Living with Stroke: A Guide for Families. Chicago, Ill: Contemporary Books, 1999.

Shinberg, E. F. Strokes: What Families Should Know. Westminister, Mary.: Random House, 1990.

Weiner, F.; Lee, M.; and Bell, H. Recovering at Home after a Stroke: A Practical Guide for You and Your Family. New York: The Body Press/Perigee Books, 1994.

Stroke

Definition

A stroke, also called a cerebral infarction, is a life-threatening condition marked by a sudden disruption in the blood supply to the brain.

Description

A disruption in the blood supply to the brain starves the brain of oxygen-rich blood and causes the nerve cells in that area to become damaged and die within minutes. The body parts controlled by those damaged brain cells lose their ability to function.

Depending on the area of the brain that is affected, a stroke can alter many aspects of a child's functioning such as speech, movement, behavior and learning. A stroke also may cause weakness or paralysis on one side of the body. The loss of function may be mild or severe, temporary or permanent.

If medical treatment begins within hours after symptoms are recognized, brain damage can be limited and the risk of permanent medical effects can be decreased.

Types of stroke

An ischemic stroke—the most common form of stroke in children under age 15—is caused by a blocked or narrowed artery. In children, blockages may be caused by a blood clot, injury to the artery, or rarely in children, atherosclerosis (build-up of fatty deposits on the blood vessel walls). A cerebral thrombosis is a blood clot that develops at the clogged part of the blood vessel. A cerebral embolism is a blood clot that travels to the clogged blood vessel from another location in the circulatory system.

A hemorrhagic stroke—the more common form of stroke in infants and children under age two—occurs when a weakened blood vessel leaks or bursts, causing bleeding in the brain tissue or near the surface of the brain.

Two types of weakened blood vessels usually cause hemorrhagic stroke, including:

• aneurysm: ballooning of a weakened area of a blood vessel
• arteriovenous malformations: cluster of abnormal blood vessels

A transient ischemic attack (TIA), also called a "mini stroke," is characterized by a short-term blood vessel obstruction or clot that tends to resolve itself quickly, usually within 10–20 minutes, or up to 24 hours. A TIA usually does not require intervention. However, a TIA is a strong indicator of an ischemic stroke and should be evaluated in the same way as a stroke to prevent a more serious attack.

In children, strokes can be categorized as:

• prenatal stroke: occurring before birth
• neonatal or perinatal stroke: occurring in infants less than 30 days old
• pediatric or childhood stroke: occurring in children aged 15 and under

Demographics

Childhood stroke is relatively rare, occurring in about two to three of every 100,000 children aged one to 14 per year. In comparison, stroke occurs in about 100 of every 100,000 adults per year. The rate of ischemic stroke and hemorrhagic stroke is similar among children aged one to 14.

Stroke occurs more frequently in children under age two, and peaks in the perinatal period. In the National Hospital Discharge Survey from 1980-1998, the rate of stroke for infants less than 30 days old (per 100,000 live births per year) was 26.4, with rates of 6.7 for hemorrhagic stroke and 17.8 for ischemic stroke.

More fatal strokes occur in African-American children than white children, mirroring the racial differences of stroke in adults. Compared to the stroke risk of white children, African-American children have an increased relative risk of 2.12, Hispanics a decreased relative risk of 0.76 and Asians have a similar risk. Boys have a 1.28-fold higher risk of stroke than girls and have a higher case-fatality rate for ischemic stroke than girls. The increased risk among African Americans is not explained by the presence of sickle cell disease, nor is the excess risk among boys explained by trauma.

Research conducted by the National Institute of Neurological Diseases and Stroke (NINDS) indicates a "stroke belt," or geographical area where fatal strokes are more predominant. This stroke belt includes Alabama, Arkansas, Georgia, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia. Researchers examined death certificates over a 19-year period and found a 21 percent higher risk of death from stroke in people under age 20 in the stroke belt states had compared with the same age group in other states. During the same period, people over age 25 in the stroke belt region had a 20 percent higher risk of death from stroke. Because the overall rate of stroke in children is low, researchers warn parents in these states not to be too alarmed. However, the findings indicate further investigation is needed.

Causes and symptoms

Causes

The cause of childhood stroke is unknown in one-third of cases, and an underlying medical condition or multiple conditions appear to contribute to over half of the cases. The most common causes of stroke are congenital (present at birth) and acquired heart diseases, and sickle cell anemia .

About 10–15 percent of children with sickle cell disease suffer a stroke, usually ischemic stroke. Sickle cell disease is a blood disorder in which the blood cells cannot carry oxygen to the brain because the blood vessels to the brain are either narrowed or closed.

One rare cause of stroke is an extreme case of the chickenpox virus, which causes a narrowing of blood vessels in the head for some children.

RISK FACTORS Although obesity , high cholesterol , high blood pressure, atherosclerosis, and smoking are common stroke risk factors in adults, they rarely contribute to stroke risk in children. Risk factors for childhood stroke include a family history of stroke, cardiovascular disease or diabetes, as well as the presence of the conditions listed below.

Some of the more common congenital heart diseases that increase the risk of childhood stroke include:

• aortic and mitral valve stenosis
• atrial septal defect
• patent ductus arteriosus (PDA)
• patent foramen ovale
• inherited blood clotting disorders
• ventricular septal defect
• hypercoagulable states

Some of the acquired heart conditions that increase the risk of childhood stroke include:

• bacterial meningitis
• endocarditis
• arrhythmia and atrial fibrillation
• artificial heart valve
• myocarditis
• cardiomyopathy
• rheumatic heart disease
• embolism
• anoxia
• antiphospholipid antibody syndrome
• encephalitis
• blood vessel disease
• certain blood disorders, such as hemophilia
• inborn errors of metabolism
• illicit drug use
• teenage pregnancy
• teen use of oral contraceptives (birth control pills)

Possible traumas that increase the risk of childhood stroke include birth injury or trauma, child abuse, or other injury or trauma.

Because of the wide range of secondary conditions that contribute to stroke, it is difficult for researchers to assess the relative contribution of each risk factor to the problem of cerebrovascular disease as a whole, according to the Child Neurology Society Ad Hoc Committee on Stroke in Children. In addition, this variability also hinders clinical research.

Symptoms

In infants and very young children, stroke symptoms are sudden and include:

• seizures
• coma
• paralysis on one side of the body
• nausea or vomiting

In older children, stroke symptoms are sudden and include:

• numbness or weakness of the face, arm, or leg, especially on one side of the body
• confusion or difficulty speaking or understanding speech
• vision difficulties, often in one eye
• hearing problems, often in one ear
• difficulty walking, dizziness or loss of balance or coordination
• severe headache
• difficulty swallowing
• nausea or vomiting
• painful or stiff neck

Other stroke signs and symptoms include:

• sudden severe headache with unknown cause
• sudden nausea or vomiting
• warm, flushed, clammy skin
• slow, full pulse
• appearance of unequal pupils
• facial "droop" on one side
• salivary drool
• urinary incontinence

If the child seems to recover quickly from these stroke symptoms, a TIA may have occurred. All neurological symptoms should serve as a stroke "warning sign" and could indicate a pending, more serious attack. The child should receive prompt evaluation so necessary preventive therapies can be initiated.

WHEN TO CALL THE DOCTOR If a child has any of the symptoms listed above, the parent or caregiver should immediately dial 9-1-1 to seek emergency care. It is important not to wait to see if symptoms subside; a stroke is a medical emergency. Until the paramedics arrive, the parent or caregiver should follow these first aid guidelines:

• Make sure the child is in a comfortable posture, lying on his or her side, so the airway does not become obstructed by drool or mucus.
• Talk reassuringly to the child, even if he or she is unconscious.
• Do not leave the child alone—constantly observe the child.
• Cover the child with a blanket or remove clothing as needed to maintain the child's normal body temperature.
• Do not give the child any medication, including aspirin; medication will be given later as needed.

Diagnosis

In most children, the diagnosis of stroke is delayed by more than 24 hours from the onset of symptoms. This delay is thought to occur because there is a lack of general awareness by physicians and families of cerebrovascular disorders in children. However, early recognition and treatment of a stroke could improve management, reduce the risk of brain damage and permanent disability, help prevent a recurrence, and initiate a proper treatment and rehabilitation program to maximize functional recovery.

The diagnosis of pediatric stroke generally occurs in the emergency room and includes:

• personal and family medical history
• review of current medications
• evaluation of other health problems
• physical examination
• brief neurological exam
• diagnostic tests

The medical history helps the physician evaluate the presence of other conditions or disorders that might have caused the stroke. The child's family medical history is evaluated to determine if there is a history of cardiovascular or neurological diseases that might increase the risk of blood clots.

The brief neurological exam includes a review of the patient's mental status, motor and sensory system, deep tendon reflexes, coordination, and walking pattern (gait). The cranial nerve function also will be evaluated and includes a review of the patient's visual function and eye movement, strength of facial muscles, the gag reflex, tongue and lip movements, ability to smell and taste, hearing, and sensation and movement of the face, head, and neck.

Questions about the child's condition may include:

• What symptoms occurred?
• When were the symptoms first noticed?
• How long did the symptoms last?
• What functions were affected?

During the physical exam, the child's pulse, blood pressure, and height and weight are checked and recorded.

Diagnostic tests include:

• Blood tests: Test used to detect the presence of any chemical abnormalities, infection, or blood clotting that may have caused the stroke.
• Magnetic resonance imaging (MRI) scan: An imaging technique that provides a detailed picture of the brain without the use of x rays. MRI uses a large magnet, radio waves and a computer to produce these images.
• Computed tomography (CT) scan: An imaging technique that shows the blood vessels in the brain. A CT scan is used to identify the area of the brain affected and to detect signs of swelling.
• Chest x ray: X rays are used to detect an enlarged heart, vascular abnormalities, or lung problems.
• Angiogram: An invasive imaging technique used to examine the blood vessels in the brain. An angiogram is only performed if the CT or MRI scans do not show conclusive results.
• Echocardiogram (echo): A graphic outline of the heart's movement, valves and chambers, used to determine if the stroke was caused by a blood clot traveling from the heart to the brain. Echo is often combined with Doppler ultrasound and color Doppler. During the echo, an ultrasound transducer (hand-held wand placed on the skin of the chest) emits high-frequency sound waves to produce pictures of the heart's valves and chambers.

MRI is more sensitive than CT scanning for the diagnosis of an ischemic stroke within 24 hours. However, the two tests are comparable when used to evaluate the effects of a hemorrhagic stroke.

In rare cases or when carotid artery disease is suspected, additional tests may include a carotid ultrasound or cerebral or carotid angiogram. Other tests to diagnose stroke may include a transcranial Doppler ultrasound and neurosonogram. In a transcranial Doppler ultrasound, sound waves are used to measure blood flow in the vessels of the brain. In a neurosonogram, ultra high frequency sound waves are used to analyze blood flow and possible blockages in the blood vessels in or leading to the brain.

If a pediatric stroke is diagnosed, additional tests may be performed to assess the overall function

• Electroencephalogram (EEG): Electrodes (small, sticky metal patches attached to the scalp) are connected by wires (leads) to an electroencephalograph machine to chart the brain's continuous electrical activity.
• Evoked potentials study: Wires attached to the scalp, neck, and limbs are connected to a computer to measure the electrical activity in certain areas of the brain and spinal cord when specific sensory nerve pathways are stimulated. The brain's electrical response to visual, auditory, and sensual stimulation is recorded.

Treatment

Initial treatment depends on the type of stroke. For an ischemic stroke, initial emergent treatment focuses on restoring blood flow to the brain. For a hemorrhagic stroke, the goal of initial treatment is to control the bleeding. Children with a hemorrhagic stroke may be transferred to a center with neurosurgical facilities so the proper treatment, such as decompression or hydrocephalus drainage, can be provided by skilled specialists.

Emergency-room treatment may include: oxygen to ensure the brain is getting the maximum amount, control of body temperature, assessment and treatment of breathing difficulties, intravenous fluids to prevent or treat dehydration , and medications to control blood pressure and prevent blood clotting. Blood transfusions may be used to treat children with sickle cell disease.

Treatment team

Treatment should be provided by a pediatric neurologist and a multi-disciplinary team of specialists that may include a physical therapist, occupational therapist, speech therapist, social worker, and other specialists as needed to meet the child's individual needs.

Medications

Adult stroke patients who receive treatment within three hours after the onset of stroke symptoms may receive a "clot-busting" medication called t-PA. However, the diagnosis of stroke is rarely made within three hours, so the use of this drug in children is uncommon.

Anticoagulant medications, including heparin or warfarin and low-dose aspirin, may be used to reduce the risk of blood clot formation. Although experience with these medications in children suggests they are safe, their use in children remains controversial because of the risk of Reye's syndrome. Sometimes the potential benefits of these medications outweigh the small risk of side effects. Researchers agree that further studies are needed to determine the proper dosage and effectiveness of aspirin and other anticoagulant medications for treating stroke in children.

The most important medication guidelines are: 1) Ensure your child takes all medications exactly as prescribed; 2) Never discontinue any medication without first talking to the child's doctor, even if the medication does not seem to be working or is causing unwanted side effects; and 3) Follow-up with the child's health care provider as recommended to monitor the effects of the medication. Frequent blood tests are required for people taking anticoagulants to evaluate the dosage and effects of the medication.

Other stroke medications that are still being tested in clinical trials include:

• Citicoline as a treatment for ischemic stroke. Studies have shown both acute and long-term neuroprotective properties of citicoline in animal models of stroke and in several human clinical trials.
• Epoetin, a synthetic version of human erythropoietin, as a treatment for ischemic stroke. Epoetin aids the body in producing red blood cells and is currently used to treat anemia associated with kidney disease or caused by some drugs.
• Early administration of magnesium to serve as a potential neuroprotective agent. Studies have shown neuroprotectant properties of magnesium sulfate in animal models of stroke, and improved outcomes following magnesium sulfate treatment in humans have been observed following small pilot studies.

Rehabilitation

After the child's condition has stabilized, rehabilitation is initiated. Rehabilitation includes physical, occupational, and speech therapy. Therapy is usually initiated as soon as possible after a stroke and is often the most intense in the early stages of recovery. Clinicians should work with the child and the parents or caregivers to develop an individual treatment plan. Specific treatment goals will vary from one child to the next but will focus on restoring maximum function and independence, helping the child return to normal activities, and improving the child's quality of life. The child's progress after rehabilitation will depend upon which area of the brain was affected, the cause of stroke, the extent of injury, and the presence of other medical conditions.

Physical therapy includes stretching exercises, muscle group strengthening exercises, and range of motion exercises to preserve flexibility and range of motion. Exercises should be practiced daily, as recommended by the physical therapist. A physical therapist can instruct the patient on proper posture guidelines to maintain proper alignment of the hips and back. Balancing rest and exercise is also important.

Occupational therapy may include splints, casts, or braces on the affected arm or leg to enable proper limb positioning, prevent joint stiffness, and maintain flexibility and range of motion. An occupational therapist can recommend assistive equipment and devices to help the child with activities of daily living, such as bathing, dressing, and eating. If a walker or wheelchair are needed, an occupational therapist can provide specific instructions.

Physical and occupational therapists can provide guidelines on how to adapt the child's home and school environments to ensure safety and comfort.

Speech therapy will focus on the child's specific needs which may include any or all aspects of language use, such as speaking, reading, writing, and understanding the spoken word. Speech and language problems (aphasia) usually occur when a stroke affects the right side of the body.

Behavioral problems and learning disabilities, such as difficulties with attention or concentration, may become apparent when the child goes to school, so specific treatments and educational assistance may be needed to address these problems. A formal assessment can help parents identify potential behavioral and learning problems.

Surgery

The need for surgical treatment for pediatric stroke will depend on a number of factors, including the type of stroke, extent of damage from stroke, the child's age, and potential benefits and risks. Sometimes urgent surgery is necessary soon after the child is admitted to the emergency room to remove a blood clot and restore oxygen flow to the brain tissue.

Treatment options for hemorrhagic stroke may include surgery, sterotactic radiotherapy, or interventional neuroradiology to treat the underlying aneurysm or arteriovenous malformation.

There are several surgical procedures to repair an aneurysm that may have caused a hemorrhagic stroke. A clip may be placed across the neck of the aneurysm (like a clip at the end of a balloon) to stop the bleeding. A newer approach is to thread a long, thin tube through the artery that leads to the aneurysm. Then a tiny coil is fed through the tube into the aneurysm "balloon" to fill the space and seal off the bleeding.

An interventional procedure called carotid angioplasty may be performed to treat a blockage or blockages in the carotid arteries. During the procedure, a tiny balloon at the end of a long, thin tube (called a catheter) is pushed through the artery to the blockage. When the balloon is inflated, it opens the artery. In addition, a mesh tube (called a stent) may be placed inside the artery to help hold it open.

Carotid endarterectomy is a surgical procedure performed to remove a blockage from the carotid artery. During the operation, the surgeon scrapes away plaque from the wall of the artery so blood can flow freely through the artery to the brain.

Intracranial bypass surgery is a surgical procedure performed to restore blood flow around a blocked blood vessel in the brain. During the surgery, a healthy blood vessel, on the outside of the scalp, is re-routed to the part of the brain that is not getting enough blood flow. This new blood vessel bypasses the blocked vessel and provides an additional blood supply to areas of the brain that were deprived of blood. When blood flow is restored, the brain works normally, and the symptoms disappear. This procedure is not as common as the other surgical treatments listed above to treat pediatric stroke but it may be used to treat recurrent TIAs.

Alternative treatment

Alternative and complementary therapies include approaches that are considered to be outside the mainstream of traditional health care.

Techniques that induce relaxation and reduce stress, such as yoga , Tai Chi, meditation, guided imagery, and relaxation training, may be helpful in controlling blood pressure. Acupuncture and biofeedback training also may help induce relaxation. Before learning or practicing any particular technique, it is important for the parent/caregiver and child to learn about the therapy, its safety and effectiveness, potential side effects, and the expertise and qualifications of the practitioner. Although some practices are beneficial, others may be harmful to certain patients.

Alternative treatments should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these techniques and treatments with the child's doctor to determine the remedies that may be beneficial for the child.

Nutritional concerns

Dietary guidelines are individualized, based on the child's age, diagnosis, overall health, and level of functioning. Specific nutritional problems, such as swallowing or feeding difficulties, may be a concern in some patients and should be managed by a team of specialists including a speech therapist. Early identification, treatment, and correction of specific feeding problems will improve the health and nutritional status of the child.

A child's self-feeding skills can impact his or her health outcome. One study indicated that 90 percent of children with good to fair motor and feeding skills reached adulthood. In contrast, a lack of self-feeding skills was associated with a six-fold increase in mortality (rate of death).

Maintaining a healthy weight is important to prevent the development of chronic diseases such as diabetes, high blood pressure (hypertension ), and heart disease.

Tube feedings may be required in some patients with failure to thrive , aspiration pneumonia , difficulty swallowing, or an inability to ingest adequate calories orally to maintain nutritional status or promote growth.

A well-balanced and carefully planned diet will help maintain general good health for children who have suffered a stroke. In general, children should follow the same low-fat, high fiber diet that is recommended for the general population.

In children older than age two, the following low-fat dietary guidelines are recommended:

• Total fat intake should comprise 30 percent or less of total calories consumed per day.
• Calories consumed as saturated fat should equal no more than 8-10 percent of total calories consumed per day.
• Total cholesterol intake should be less than 300 mg/dl per day.

If the child has high blood pressure, the DASH diet is recommended. The "Dietary Approaches to Stop Hypertension (DASH)" study, sponsored by the National Institutes of Health (NIH), showed that elevated blood pressures were reduced by an eating plan that emphasized fruits, vegetables, and low-fat dairy foods and was low in saturated fat, total fat, and cholesterol. The DASH diet includes whole grains, poultry, fish, and nuts. Fats, red meats, sodium, sweets, and sugar-sweetened beverages are limited. Sodium should also be reduced to no more than 1,500 milligrams per day.

Prognosis

Cerebrovascular disorders are among the top 10 causes of death in children, with rates highest in the first year of life. From 1979 to 1998 in the United States, childhood mortality from stroke declined sharply, by 58 percent, with reductions in all major subtypes: ischemic stroke decreased by 19 percent, subarachnoid hemorrhage by 79 percent, and intracerebral hemorrhage by 54 percent.

Some children survive a pediatric stroke with no life-long consequences. In other children, long-term complications of stroke may develop right away or within months to years after a stroke. According to a 2000 study published in the Journal of Child Neurology, the outcome of childhood stroke was a moderate or severe deficit in 42 percent of cases. Adverse outcomes after childhood stroke—including death in 10 percent, recurrence in 20 percent, and neurological deficits in two-thirds of survivors—can be reduced with available stroke treatments.

When a stroke affects a child whose brain is still developing, it is thought that the developing brain may be able to compensate for the functions that were lost as a result of a stroke.

Recovery from stroke is different with each child. Overall, the degree of permanent disability after a stroke is less in children than in adults. Speech and language problems usually improve rapidly in the first year after a stroke. Children may only have minor delays in the development of coordinated movement or in cognitive functioning. Almost all children recover the ability to walk independently after a stroke, unless there is another condition that causes disability. Recovery of function in the affected arm and hand is usually the most significant movement problem after a stroke. Most children who suffer from a stroke can expect to lead independent lives as adults.

Prevention

Despite current treatment, one out of 10 children with ischemic stroke will have a recurrence within five years. Although there is a high risk of repeat strokes in patients with sickle cell anemia, the risk can be reduced with regular blood transfusions. If no cause of the stroke was identified, the risk of a recurrence is low. If a cause was identified, the underlying condition should be treated, and anticoagulant or low-dose aspirin therapy may be initiated, depending on the child's diagnosis.

There is no screening for stroke, but screening exists for many of its risk factors. To prevent stroke, risk factors should be treated and managed by the child's primary care doctor or specialist. The doctor can advise if specific preventive treatment is needed.

Management of high cholesterol—especially high LDL (low-density lipoprotein) levels—high blood pressure and diabetes can help reduce the risk of a stroke.

Nutritional concerns

An adequate intake of folic acid (vitamin B9) has been linked to the prevention of stroke and heart disease by lowering homocysteine, an amino acid related to the early development of cardiovascular disease when high levels are present in the blood. Dietary sources of folic acid include: vegetables, especially green vegetables; potatoes; cereal and cereal products; fruits; and organ meats (liver or kidney). It is best to eat fresh fruits and vegetables whenever possible to get the most vitamins . Recommended daily intake in micrograms (mcg) for folic acid supplements (oral tablets) include: 25–100 mcg in newborns to age three; 75–400 mcg in children aged four to six; 100-400 mcg in children aged seven to 10; and 150–400 mcg in children aged 11 and above.

Vitamin K is an important nutrient needed to regulate normal blood clotting. A diet deficient in vitamin K can cause prolonged blood-clotting time and easy bleeding and bruising. Vitamin K is found in: alfalfa, asparagus, broccoli, Brussels sprouts, cabbage cheddar cheese, green tea, green leafy lettuce, liver, seaweed, spinach, and turnip greens. Recommended daily intake for vitamin K supplements (for patients not on anticoagulant therapy) include: 10 mcg in newborns to age three; 20 mcg in children aged four to six; 30 mcg in children aged seven to 14; 65 mcg in boys and 55 mcg in girls aged 15–18; 70–80 mcg for males over age 18 and 60–65 mcg for females over age 18. If the patient is taking anticoagulant medications, vitamin K supplements are not recommended, and foods high in vitamin K are limited, since they counteract the action of the medication.

Vitamin E and beta carotene supplements were once thought to help decrease the risk of stroke and prevent the development of heart disease, but newer studies disprove their effectiveness. Researchers at The Cleveland Clinic Heart Center performed a meta-analysis of seven large randomized trials of vitamin E (given alone or in combination with other antioxidants) and eight of beta carotene. All trials included 1,000 or more patients and follow-up ranged from 1.4 to 12 years. The doses of vitamin E given in these trials ranged from 50–800 international units (IU) and 15–50 milligrams (mg) for beta carotene. The meta-analysis reviewed the effect of these antioxidants on death from cardiovascular disease or from any other cause ("all-cause mortality").

Their findings, published in the June, 2003 issue of The Lancet journal, do not support the continued use of vitamin E supplementation nor the inclusion of vitamin E in further studies. Regardless of the dosage given or the patient population, Vitamin E did not provide any benefit in lowering mortality compared to control treatments, and it did not significantly decrease the risk of cardiovascular death or stroke (cerebrovascular accident). In addition, they recommend that vitamin supplements containing beta carotene be "actively discouraged" because of the small but statistically significant increased risk of death. Researchers discourage further study of beta carotene because of the mortality risk.

Even though studies have demonstrated that vitamin E and beta carotene supplements do not reduce stroke risk, foods rich in antioxidants are still encouraged because they also contain beneficial nutrients such as flavonoids and lycopenes that are not usually included in standard oral vitamin supplements. A diet rich in antioxidant-containing foods, such as fruits, vegetables and whole grains, is linked to a reduced risk of cardiovascular disease.

Dietary supplements should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these nutrition supplements with the child's doctor to determine the remedies that may be beneficial for the child.

Parental concerns

It is common for a child to feel sad or depressed after a stroke. These emotions may be the result of not knowing what to expect or not being able to do simple tasks without becoming overly tired. Temporary feelings of sadness are normal, and should gradually go away within a few weeks, as the child starts a rehabilitation program and returns to some of his or her normal routines and activities.

When a depressed mood is severe and accompanied by other symptoms that persist every day for two or more weeks, the parent should ask for a referral to a mental health professional who can help the child cope and recover. There are many treatments for depression. A healthy lifestyle including regular exercise, proper sleep , a well-balanced diet, as well as relaxation and stress management techniques can help manage depression. Major depressive disorder may be treated with antidepressants , psychotherapy (supportive counseling or "talk therapy"), or a combination of both.

Regular follow-up visits with the child's health care provider will help identify and manage risk factors and other medical conditions. If the child has a known medical condition that increases the risk of stroke, it is important for parents and caregivers to learn the warning signs and symptoms of stroke in children and infants. If the child experiences any unexpected neurological problem, the parent should have the child evaluated by a physician. Lastly, it is important for parents to carefully follow the child's treatment plan, including following the medication schedule exactly as prescribed.

Resources

BOOKS

Burkman, Kip. The Stroke Recovery Book: A Guide for Patients and Families. Nebraska: Addicus Books, Inc., May, 1998.

Senelick, Richard C., Peter W. Rossi, and Karla Dougherty. Living with Stroke: A Guide For Families: Help and New Hope for All Those Touched by Stroke. New York: McGraw-Hill/Contemporary Books, June, 1999.

Zimmer, Judith and John P. Cooke. The Cardiovascular Cure: How to Strengthen Your Self-Defense Against Heart Attack and Stroke. New York: Broadway Books, August, 2002.

PERIODICALS

Abram, Harry S., MD. "Childhood Strokes: Evaluation and Treatment." Duval County Medical Society. www.dchmsonline.org/jax-medicine/1998journals/november1998/childhoodstrokes.htm.

deVeber, G., ES Roach, AR Riela, and M. Wiznitzer. "Stroke in Children: Recognition, Treatment, and Future Directions." Seminars in Pediatric Neurology. 7:4 (December, 2000): 309-317.

deVeber, G., ES Roach, AR Riela, and M. Wiznitzer. "Recognition and Treatment of Stroke in Children." Child Neurology Society Ad Hoc Committee on Stroke in Children. July, 2001.

Kirkham, FJ. "Stroke in Childhood." Archives of Disease in Childhood. 81 (July, 1999): 85-89.

Nicolaides, P. and R.E. Appleton. "Stroke in Children." Developmental Medicine and Child Neurology. 38:2 (February, 1996): 172-180.

ORGANIZATIONS

American Stroke Foundation. 11902 Lowell, Overland Park, KS 66213. (913) 649-1776. <http://www.americanstroke.org>.

KEY TERMS

Activities of daily living (ADL) —The activities performed during the course of a normal day, for example, eating, bathing, dressing, toileting, etc.

Aneurysm —A weakened area in the wall of a blood vessel which causes an outpouching or bulge. Aneurysms may be fatal if these weak areas burst, resulting in uncontrollable bleeding.

Anoxia —Lack of oxygen.

Antibody —A special protein made by the body's immune system as a defense against foreign material (bacteria, viruses, etc.) that enters the body. It is uniquely designed to attack and neutralize the specific antigen that triggered the immune response.

Antiphospholipid antibody syndrome —An immune disorder that occurs when the body recognizes phospholipids (part of a cell's membrane) as foreign and produces abnormal antibodies against them. This syndrome is associated with abnormal blood clotting, low blood platelet counts, and migraine headaches.

Aorta —The main artery located above the heart that pumps oxygenated blood out into the body. The aorta is the largest artery in the body.

Aortic valve —The valve between the heart's left ventricle and ascending aorta that prevents regurgitation of blood back into the left ventricle.

Aortic valve stenosis —Narrowing of the aortic valve.

Aphasia —The loss of the ability to speak, or to understand written or spoken language. A person who cannot speak or understand language is said to be aphasic.

Arteriosclerosis —A chronic condition characterized by thickening, loss of leasticity, and hardening of the arteries and the build-up of plaque on the arterial walls. Arteriosclerosis can slow or impair blood circulation. It includes atherosclerosis, but the two terms are often used synonymously.

Artery —A blood vessel that carries blood away from the heart to the cells, tissues, and organs of the body.

Atrial —Referring to the upper chambers of the heart.

Atrial fibrillation —A type of heart arrhythmia in which the upper chamber of the heart quivers instead of pumping in an organized way. In this condition, the upper chambers (atria) of the heart do not completely empty when the heart beats, which can allow blood clots to form.

Atrial septal defect —An opening between the right and left atria (upper chambers) of the heart.

Cardiologist —A physician who specializes in diagnosing and treating heart diseases.

Central nervous system —Part of the nervous system consisting of the brain, cranial nerves, and spinal cord. The brain is the center of higher processes, such as thought and emotion and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system, that is the nerves present in the rest of body.

Cerebrospinal fluid —The clear, normally colorless fluid that fills the brain cavities (ventricles), the subarachnoid space around the brain, and the spinal cord and acts as a shock absorber.

Decompression —A decrease in pressure from the surrounding water that occurs with decreasing diving depth.

Dysphagia —Difficulty in swallowing.

Echocardiogram —A record of the internal structures of the heart obtained from beams of ultrasonic waves directed through the wall of the chest.

Electrocardiagram (ECG, EKG) —A record of the electrical activity of the heart, with each wave being labeled as P, Q, R, S, and T waves. It is often used in the diagnosis of cases of abnormal cardiac rhythm and myocardial damage.

Embolus —Plural, emboli. An embolus is something that blocks the blood flow in a blood vessel. It may be a gas bubble, a blood clot, a fat globule, a mass of bacteria, or other foreign body that forms somewhere else and travels through the circulatory system until it gets stuck.

Encephalitis —Inflammation of the brain, usually caused by a virus. The inflammation may interfere with normal brain function and may cause seizures, sleepiness, confusion, personality changes, weakness in one or more parts of the body, and even coma.

Graft —A transplanted organ or other tissue.

Heart attack —Damage that occurs to the heart when one of the coronary arteries becomes narrowed or blocked.

Hemiparesis —Weakness on one side of the body.

Hemiplegia —Paralysis of one side of the body.

Hydrocephalus —An abnormal accumulation of cerebrospinal fluid within the brain. This accumulation can be harmful by pressing on brain structures, and damaging them.

Hypercoagulable states —Also called thromboembolic state or thrombophilia. A condition characterized by excess blood clotting.

Hypertension —Abnormally high arterial blood pressure, which if left untreated can lead to heart disease and stroke.

Intracerebral hemorrhage —A cause of some strokes in which vessels within the brain begin bleeding.

Ischemia —A decrease in the blood supply to an area of the body caused by obstruction or constriction of blood vessels.

Mitral valve stenosis —Narrowing of the mitral valve.

Neurologist —A doctor who specializes in disorders of the nervous system, including the brain, spinal cord, and nerves.

Neurosurgeon —Physician who performs surgery on the nervous system.

Occupational therapist —A healthcare provider who specializes in adapting the physical environment to meet a patient's needs. An occupational therapist also assists patients and caregivers with activities of daily living and provide instructions on wheelchair use or other adaptive equipment.

Patent ductus arteriosus —A congenital defect in which the temporary blood vessel connecting the left pulmonary artery to the aorta in the fetus doesn't close after birth.

Patent foramen ovale (PFO) —A congenital heart defect characterized by an open flap that remains between the two upper chambers of the heart (the left and right atria). This opening can allow a blood clot from one part of the body to travel through the flap and up to the brain, causing a stroke.

Physiatrist —A physician who specializes in physical medicine and rehabilitation.

Physical therapist —A healthcare provider who teaches patients how to perform therapeutic exercises to maintain maximum mobility and range of motion.

Reye's syndrome —A serious, life-threatening illness in children, usually developing after a bout of flu or chickenpox, and often associated with the use of aspirin. Symptoms include uncontrollable vomiting, often with lethargy, memory loss, disorientation, or delirium. Swelling of the brain may cause seizures, coma, and in severe cases, death.

Stent —A slender hollow catheter or rod placed within a vessel or duct to provide support or to keep it open.

Subarachnoid hemorrhage —A collection of blood in the subarachnoid space, the space between the arachnoid and pia mater membranes that surround the brain. This space is normally filled with cerebrospinal fluid. A subarachnoid hemorrhage can lead to stroke, seizures, permanent brain damage, and other complications.

Unilateral neglect —Also called one-sided neglect. A side effect of stroke in which the stroke survivor ignores or forgets the weaker side of the body caused by the stroke.

Vein —A blood vessel that returns blood to the heart from the body. All the veins from the body converge into two major veins that lead to the right atrium of the heart. These veins are the superior vena cava and the inferior vena cava. The pulmonary vein carries the blood from the right ventricle of the heart into the lungs.

Ventricle septal defect —A hole in the wall (septum) between the lower chambers of the heart.

Ventricles —The lower pumping chambers of the heart. The ventricles push blood to the lungs and the rest of the body.

Ventricles of the brain —The spaces within the brain where cerebrospinal fluid is made.

American Stroke Association, A Division of American Heart Association, 7272 Greenville Ave., Dallas, TX 75231. (888) 4-STROKE (787653). E-mail: strokeassociation@heart.org. <http://www.strokeassociation.org>.

Children's Hemiplegia and Stroke Association. 4101 W. Green Oaks, Ste. 305, PMB 149, Arlington, TX 76016. (817) 492-4325. E-mail: info@chasa.org. <http://www.chasa.org>.

National Heart, Lung and Blood Institute. National Institutes of Health, Building 1, 1 Center Dr., Bethesda, MD 20892. E-mail: NHLBIinfo@rover.nhlbi. <http://www.nhlbi.nih.gov>.

National Institute on Disability and Rehabilitation Research, Office of Special Education and Rehabilitative Services, U.S. Department of Education, 400 Maryland Ave. S.W., Washington, DC 20202-7100. (202) 245-7640. <http://www.ed.gov/about/offices/list/osers/nidrr/>.

National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health. P.O. Box 5801, Bethesda, MD 20824. (800) 352-9424 or (301) 496-5751. <http://www.ninds.nih.gov/about_ninds/>.

National Rehabilitation Information Center (NARIC).4200 Forbes Blvd., Ste. 202, Lanham, MD 20700. (800) 346-2742 or (301) 459-5900. <http://www.naric.com>.

National Stroke Association. 9707 E. Easter Ln., Englewood, CO 80112-3747. (800) STROKES (787-6537) or (303) 649-9299. <http://www.stroke.org>.

Stroke Clubs International. 805 12th St. Galveston, TX 77550. (409) 762-1022 attn. Ellis Williamson. E-mail: strokeclub@aol.com.

WEB SITES

The Brain Attack Coalition. <www.stroke-site.org>

The Brain Matters, American Academy of Neurology Foundation. <www.thebrainmatters.org>

Different Strokes—A Charity for Younger Stroke Survivors. <www.differentstrokes.co.uk/>

HeartCenterOnline. <www.heartcenteronline.com>

HemiHelp—Information and Support for Children and Young People with Hemiplegia. <www.hemihelp.org.uk>

Pediatric Stroke Network. <www.pediatricstrokenetwork.com>

Angela M. Costello

Stroke

Definition

A stroke is the sudden death of brain cells in a localized area due to inadequate blood flow.

Description

A stroke occurs when blood flow is interrupted to part of the brain. Without blood to supply oxygen and nutrients and to remove waste products, brain cells quickly begin to die. Depending on the region of the brain affected, a stroke may cause paralysis, speech impairment, loss of memory and reasoning ability, coma, or death. A stroke also is sometimes called a brain attack or a cerebrovascular accident (CVA).

Some important stroke statistics include:

• more than one-half million people in the United States experience a new or recurrent stroke each year
• stroke is the third leading cause of death in the United States and the leading cause of disability
• stroke kills about 160,000 Americans each year, or almost one out of three stroke victims
• three million Americans are currently permanently disabled from stroke
• in the United States, stroke costs about $30 billion per year in direct costs and loss of productivity
• two-thirds of strokes occur in people over age 65 but they can occur at any age
• strokes affect men more often than women, although women are more likely to die from a stroke

• strokes affect blacks more often than whites, and are more likely to be fatal among blacks

Stroke is a medical emergency requiring immediate treatment. Prompt treatment improves the chances of survival and increases the degree of recovery that may be expected. A person who may have suffered a stroke should be seen in a hospital emergency room without delay. Treatment to break up a blood clot, the major cause of stroke, must begin within three hours of the stroke to be effective. Improved medical treatment of all types of stroke has resulted in a dramatic decline in death rates in recent decades. In 1950, nine in ten died from stroke, compared to slightly less than one in three in the twenty-first century. However, about two-thirds of stroke survivors will have disabilities ranging from moderate to severe.

Causes and symptoms

Causes

There are four main types of stroke. Cerebral thrombosis and cerebral embolism are caused by blood clots that block an artery supplying the brain, either in the brain itself or in the neck. These account for 70-80% of all strokes. Subarachnoid hemorrhage and intracerebral hemorrhage occur when a blood vessel bursts around or in the brain.

Cerebral thrombosis occurs when a blood clot, or thrombus, forms within the brain itself, blocking the flow of blood through the affected vessel. Clots most often form due to "hardening" (atherosclerosis ) of brain arteries. Cerebral thrombosis occurs most often at night or early in the morning. Cerebral thrombosis is often preceded by a transient ischemic attack, or TIA, sometimes called a "mini-stroke." In a TIA, blood flow is temporarily interrupted, causing short-lived stroke-like symptoms. Recognizing the occurrence of a TIA, and seeking immediate treatment, is an important step in stroke prevention.

Cerebral embolism occurs when a blood clot from elsewhere in the circulatory system breaks free. If it becomes lodged in an artery supplying the brain, either in the brain or in the neck, it can cause a stroke. The most common cause of cerebral embolism is atrial fibrillation, a disorder of the heart beat. In atrial fibrillation, the upper chambers (atria) of the heart beat weakly and rapidly, instead of slowly and steadily. Blood within the atria is not completely emptied. This stagnant blood may form clots within the atria, which can then break off and enter the circulation. Atrial fibrillation is a factor in about 15% of all strokes. The risk of a stroke from atrial fibrillation can be dramatically reduced with daily use of anticoagulant medication.

Hemorrhage, or bleeding, occurs when a blood vessel breaks, either from trauma or excess internal pressure. The vessels most likely to break are those with preexisting defects such as an aneurysm. An aneurysm is a "pouching out" of a blood vessel caused by a weak arterial wall. Brain aneurysms are surprisingly common. According to autopsy studies, about 6% of all Americans have them. Aneurysms rarely cause symptoms until they burst. Aneurysms are most likely to burst when blood pressure is highest, and controlling blood pressure is an important preventive strategy.

Intracerebral hemorrhage affects vessels within the brain itself, while subarachnoid hemorrhage affects arteries at the brain's surface, just below the protective arachnoid membrane. Intracerebral hemorrhages represent about 10% of all strokes, while subarachnoid hemorrhages account for about 7%.

In addition to depriving affected tissues of blood supply, the accumulation of fluid within the inflexible skull creates excess pressure on brain tissue, which can quickly become fatal. Nonetheless, recovery may be more complete for a person who survives hemorrhage than for one who survives a clot, because the blood deprivation effects usually are not as severe.

Death of brain cells triggers a chain reaction in which toxic chemicals created by cell death affect other nearby cells. This is one reason why prompt treatment can have such a dramatic effect on final recovery.

Risk factors

Risk factors for stroke involve age, sex, heredity, predisposing diseases or other medical conditions, use of certain medications, and lifestyle choices:

• Age and sex. The risk of stroke increases with age, doubling for each decade after age 55. Men are more likely to have a stroke than women.
• Heredity. Blacks, Asians, and Hispanics have higher rates of stroke than do whites, related partly to higher blood pressure. People with a family history of stroke are at greater risk.
• Diseases. Stroke risk is increased for people with diabetes, heart disease (especially atrial fibrillation), high blood pressure, prior stroke, or TIA. Risk of stroke increases tenfold for someone with one or more TIAs.
• Other medical conditions. Stroke risk increases with obesity, high blood cholesterol level, or high red blood cell count.
• Hormone replacement therapy. In mid-2003, a large clinical trial called the Women's Health Initiative was halted when researchers discovered several potentially dangerous effects of combined hormone replacement therapy on postmenopausal women. In addition to increasing the risk of some cancers and dementia, combined estrogen and progesterone therapy increased risk of ischemic stroke by 31% among study participants.
• Lifestyle choices. Stroke risk increases with cigarette smoking (especially if combined with the use of oral contraceptives ), low level of physical activity, alcohol consumption above two drinks per day, or use of cocaine or intravenous drugs.

Symptoms

Symptoms of an embolic stroke usually come on quite suddenly and are at their most intense right from the start, while symptoms of a thrombotic stroke come on more gradually. Symptoms may include:

• blurring or decreased vision in one or both eyes
• severe headache, often described as "the worst headache of my life"
• weakness, numbness, or paralysis of the face, arm, or leg, usually confined to one side of the body
• dizziness, loss of balance or coordination, especially when combined with other symptoms

Diagnosis

The diagnosis of stroke is begun with a careful medical history, especially concerning the onset and distribution of symptoms, presence of risk factors, and the exclusion of other possible causes. A brief neurological exam is performed to identify the degree and location of any deficits, such as weakness, incoordination, or visual losses.

Once stroke is suspected, a computed tomography scan (CT scan) or magnetic resonance imaging (MRI) scan is performed to distinguish a stroke caused by blood clot from one caused by hemorrhage, a critical distinction that guides therapy. Blood and urine tests are done routinely to look for possible abnormalities.

Other investigations that may be performed to guide treatment include an electrocardiogram, angiography, ultrasound, and electroencephalogram.

Treatment

Emergency treatment

Emergency treatment of stroke from a blood clot is aimed at dissolving the clot. This "thrombolytic therapy" currently is performed most often with tissue plasminogen activator, or t-PA. t-PA must be administered within three hours of the stroke event. Therefore, patients who awaken with stroke symptoms are ineligible for t-PA therapy, as the time of onset cannot be accurately determined. t-PA therapy has been shown to improve recovery and decrease long-term disability in selected patients. t-PA therapy carries a 6.4% risk of inducing a cerebral hemorrhage, and is not appropriate for patients with bleeding disorders, very high blood pressure, known aneurysms, any evidence of intracranial hemorrhage, or incidence of stroke, head trauma, or intracranial surgery within the past three months. Patients with clot-related (thrombotic or embolic) stroke who are ineligible for t-PA treatment may be treated with heparin or other blood thinners, or with aspirin or other anti-clotting agents in some cases.

Emergency treatment of hemorrhagic stroke is aimed at controlling intracranial pressure. Intravenous urea or mannitol plus hyperventilation is the most common treatment. Corticosteroids also may be used. Patients with reversible bleeding disorders, such as those due to anticoagulant treatment, should have these bleeding disorders reversed, if possible.

Surgery for hemorrhage due to aneurysm may be performed if the aneurysm is close enough to the cranial surface to allow access. Ruptured vessels are closed off to prevent rebleeding. For aneurysms that are difficult to reach surgically, endovascular treatment may be used. In this procedure, a catheter is guided from a larger artery up into the brain to reach the aneurysm. Small coils of wire are discharged into the aneurysm, which plug it up and block off blood flow from the main artery.

Rehabilitation

Rehabilitation refers to a comprehensive program designed to regain function as much as possible and compensate for permanent losses. Approximately 10% of stroke survivors are without any significant disability and able to function independently. Another 10% are so severely affected that they must remain institutionalized for severe disability. The remaining 80% can return home with appropriate therapy, training, support, and care services.

Rehabilitation is coordinated by a team of medical professionals and may include the services of a neurologist, a physician who specializes in rehabilitation medicine (physiatrist), a physical therapist, an occupational therapist, a speech-language pathologist, a nutritionist, a mental health professional, and a social worker. Rehabilitation services may be provided in an acute care hospital, rehabilitation hospital, long-term care facility, outpatient clinic, or at home.

The rehabilitation program is based on the patient's individual deficits and strengths. Strokes on the left side of the brain primarily affect the right half of the body, and vice versa. In addition, in left brain dominant people, who constitute a significant majority of the population, left brain strokes usually lead to speech and language deficits, while right brain strokes may affect spatial perception. Patients with right brain strokes also may deny their illness, neglect the affected side of their body, and behave impulsively.

Rehabilitation may be complicated by cognitive losses, including diminished ability to understand and follow directions. Poor results are more likely in patients with significant or prolonged cognitive changes, sensory losses, language deficits, or incontinence.

PREVENTING COMPLICATIONS. Rehabilitation begins with prevention of stroke recurrence and other medical complications. The risk of stroke recurrence may be reduced with many of the same measures used to prevent stroke, including quitting smoking and controlling blood pressure.

One of the most common medical complications following stroke is deep venous thrombosis, in which a clot forms within a limb immobilized by paralysis. Clots that break free often become lodged in an artery feeding the lungs. This type of pulmonary embolism is a common cause of death in the weeks following a stroke. Resuming activity within a day or two after the stroke is an important preventive measure, along with use of elastic stockings on the lower limbs. Drugs that prevent clotting may be given, including intravenous heparin and oral warfarin.

Weakness and loss of coordination of the swallowing muscles may impair swallowing (dysphagia), and allow food to enter the lower airway. This may lead to aspiration pneumonia, another common cause of death shortly after a stroke. Dysphagia may be treated with retraining exercises and temporary use of pureed foods.

Depression occurs in 30-60% of stroke patients. Antidepressants and psychotherapy may be used in combination.

Other medical complications include urinary tract infections, pressure ulcers, falls, and seizures.

TYPES OF REHABILITATIVE THERAPY. Brain tissue that dies in a stroke cannot regenerate. In some cases, the functions of that tissue may be performed by other brain regions after a training period. In other cases, compensatory actions may be developed to replace lost abilities.

Physical therapy is used to maintain and restore range of motion and strength in affected limbs, and to maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for instance). The physical therapist advises on mobility aids such as wheelchairs, braces, and canes. In the recovery period, a stroke patient may develop muscle spasticity and contractures, or abnormal contractions. Contractures may be treated with a combination of stretching and splinting.

Occupational therapy improves self-care skills such as feeding, bathing, and dressing, and helps develop effective compensatory strategies and devices for activities of daily living. A speech-language pathologist focuses on communication and swallowing skills. When dysphagia is a problem, a nutritionist can advise alternative meals that provide adequate nutrition.

Mental health professionals may be involved in the treatment of depression or loss of thinking (cognitive) skills. A social worker may help coordinate services and ease the transition out of the hospital back into the home. Both social workers and mental health professionals may help counsel the patient and family during the difficult rehabilitation period. Caring for a person affected with stroke requires learning a new set of skills and adapting to new demands and limitations. Home caregivers may develop stress, anxiety, and depression. Caring for the caregiver is an important part of the overall stroke treatment program.

Support groups can provide an important source of information, advice, and comfort for stroke patients and for caregivers. Joining a support group can be one of the most important steps in the rehabilitation process.

Prognosis

Stroke is fatal for about 27% of white males, 52% of black males, 23% of white females, and 40% of black females. Stroke survivors may be left with significant deficits. Emergency treatment and comprehensive rehabilitation can significantly improve both survival and recovery. A 2003 study found that treating people who have had a stroke with certain antidepressant medications, even if they were not depressed, could increase their chances of living longer. People who received the treatment were less likely to die from cardiovascular events than those who did not receive antidepressant drugs.

Prevention

Damage from stroke may be significantly reduced through emergency treatment. Knowing the symptoms of stroke is as important as knowing those of a heart attack. Patients with stroke symptoms should seek emergency treatment without delay, which may mean dialing 911 rather than their family physician.

The risk of stroke can be reduced through lifestyle changes:

• quitting smoking
• controlling blood pressure
• getting regular exercise
• keeping body weight down
• avoiding excessive alcohol consumption
• getting regular checkups and following the doctor's advice regarding diet and medicines, particularly hormone replacement therapy.

Treatment of atrial fibrillation may significantly reduce the risk of stroke. Preventive anticoagulant therapy may benefit those with untreated atrial fibrillation. Warfarin (Coumadin) has proven to be more effective than aspirin for those with higher risk. A new drug called ximelagatran (Exanta) with fewer side effects has been introduced in Europe. The drug's manufacturer was applying for FDA approval to market the drug for use in preventing stroke and other thromboembolic complications in early 2004.

In 2003, physicians at the Framingham Heart Study derived new risk scores to help physicians determine which patients with new onset of atrial fibrillation are at higher risk for stroke alone or for stroke or death. Screening for aneurysms may be an effective preventive measure in those with a family history of aneurysms or autosomal polycystic kidney disease, which tends to be associated with aneurysms.

Resources

PERIODICALS

"HRT Increases Risk of Dementia and Stroke." Contemporary OB/GYN July 2003: 16-21.

"New Classification Scheme Helpful to Predict Risk of Stroke or Death." Heart Disease Weekly September 14, 2003: 3.

"New Drug Application Submitted to FDA for Exanta." Heart Disease Weekly January 25, 2004: 79.

"New Stroke Prevention Drug." Chemist & Druggist September 13, 2003: 24.

"Post-stroke Antidepressant Treatment Appears to Reduce Death Rate." Heart Disease Weekly October 26, 2003: 56.

ORGANIZATIONS

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. 〈http://www.americanheart.org〉.

National Stroke Association. 9707 E. Easter Lane, Englewood, Co. 80112. (800) 787-6537. 〈http://www.stroke.org〉.

KEY TERMS

Aneurysm— A pouchlike bulging of a blood vessel. Aneurysms can rupture, leading to stroke.

Atrial fibrillation— A disorder of the heart beat associated with a higher risk of stroke. In this disorder, the upper chambers (atria) of the heart do not completely empty when the heart beats, which can allow blood clots to form.

Cerebral embolism— A blockage of blood flow through a vessel in the brain by a blood clot that formed elsewhere in the body and traveled to the brain.

Cerebral thrombosis— A blockage of blood flow through a vessel in the brain by a blood clot that formed in the brain itself.

Intracerebral hemorrhage— A cause of some strokes in which vessels within the brain begin bleeding.

Subarachnoid hemorrhage— A cause of some strokes in which arteries on the surface of the brain begin bleeding.

Tissue plasminogen activator (tPA)— A substance that is sometimes given to patients within three hours of a stroke to dissolve blood clots within the brain.

Stroke

Definition

Brain cells need oxygen and nutrients to function properly. When blood flow to the brain is interrupted, brain cells can begin to die and a person can experience a stroke, also called a brain attack. Damage from a stroke can temporarily or permanently disable a person's movement, speech, and cognition.

Description

A stroke occurs when blood flow to the brain is blocked or stopped. Strokes generally fall into two categories: strokes that occur when blood flow is blocked and strokes that occur because of bleeding in the brain.

Ischemic strokes are the most common cause of stroke and occur when a blood vessel in the brain or neck becomes blocked. Ischemic strokes comprise 87 percent of all strokes, and are not generally fatal.

Three conditions may contribute to the ischemia , or blockage.

Thrombosis: When a blood clot forms in a blood vessel in the brain or neck. Embolism: When a clot moves from another part of the body to the brain or neck. Stenosis: When an artery in or leading to the brain becomes severely narrowed and impedes blood flow.

Prior to an ischemic stroke, a person may experience mini strokes, also known as transient ischemic attacks (TIA). These strokes have symptoms similar to those of a stroke, but the symptoms are temporary and disappear. For most people, TIAs do not precede a stroke, but among people who have had one or more TIAs, more than a third will later have a stroke.

Strokes that occur because of bleeding in the brain are called hemorrhagic strokes. Intracerebral hemorrhages comprise 10 percent of all strokes. This type of hemorrhagic stroke occurs when a diseased blood vessel inside the brain bursts and blood begins leaking inside the brain. Subarachnoid hemorrhages, which occur when a blood vessel outside the brain ruptures and causes the skull surrounding the brain to fill with blood, comprise 3 percent of all strokes.

Treating and rehabilitating stroke victims poses an enormous cost to the U.S. health care system. It is estimated that in 2008, the direct and indirect costs of stroke will reach $65.5 billion.

Demographics

Stroke ranks as the third leading killer in the United States, behind heart disease and cancer . According to the American Stroke Association, one out of every 16 deaths in 2004 was attributable to stroke. Stroke also leads the list of causes of serious, long-term disability in the United States.

New strokes are more common than recurrent strokes. About 780,000 people experience strokes annually, about 600,000 of which are new strokes and 180,000 of which are recurrent strokes.

Among people ages 55 to 74, men have a slightly higher risk of stroke than women. In people ages 75 to 84, men and women have a similar risk of stroke. In people 85 and older, men are less likely to have a stroke than women. Also, more women die of stroke every year, in part because as a group, women live longer than men. Sixty-one percent of U.S. stroke deaths occur in women.

Stroke incidence also varies depending on racial/ethnic group. Compared to whites, blacks have almost twice the risk of having a first-time stroke and they have a greater risk of death due to stroke. Mexican Americans also have an increased incidence of stroke overall, compared to whites, and an increased risk of having a stroke at a younger age.

In the United States, stroke risk and mortality rates may also be tied to geographic region. Researchers have found that people living in the “Stroke Belt,” a region in the southwestern part of the United States that includes Alabama, Arkansas, Georgia, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia, had stroke death rates more than 10 percent higher than the U.S. average. Men and women in both black and white ethnic groups living in the Stroke Belt had higher stroke death rates than their counterparts in other regions of the country.

Causes and symptoms

Several untreatable and treatable risk factors exist that increase a person's risk of having a stroke.

Risk factors for stroke that cannot be changed include:

• Age: According to the American Stroke Association, the risk of having a stroke doubles for each decade of life after age 55.
• Gender: Overall men have a greater risk of stroke, but women have a greater risk of death due to stroke.
• Family history and ethnicity: If a close relative (parent, grandparent, or sibling) has had a stroke, a person has a greater risk of having one, too. In addition, blacks have a greater stroke risk than whites.
• Having had stroke warning signs or a previous stroke.

The good news for many older adults is that the stroke risk factors that follow can be reduced by making some changes to lifestyle, exercise habits, and nutrition.

• High blood pressure, also called hypertension, is one of the main factors that puts a person at risk for stroke.
• Smoking: Dependence on cigarettes damages the cardiovascular system and increases the risk of stroke. The risk of ischemic stroke in smokers is double that of nonsmokers.
• Heart disease: People with atherosclerosis, or fatty deposit buildup on the walls of the arteries, are prone to having narrowed arteries that may become blocked by blood clots. Older adults with heart defects or heart failure also have an increased risk of stroke.
• Atrial fibrillation: This problem with the heart's rhythm raises the risk of blood clots and increases a person's risk of stroke five-fold.
• Taking estrogen plus progestin during menopause: A large clinical trial in women found that taking estrogen plus progestin increased ischemic stroke risk by 44 percent.
• Diabetes: Having diabetes on its own increases a person's risk for stroke, but having high cholesterol, high blood pressure, and being overweight, conditions that often go hand in hand with diabetes, send stroke risk percentages spiraling higher.
• High cholesterol: Having high cholesterol levels increases the risk for stroke.
• Depression: In people under age 65, risk of stroke was more than 5 times higher in people with depressive symptoms.
• Poor diet and physical inactivity: High-fat, high-sodium, high-cholesterol diets and lack of exercise contribute to numerous medical problems and increase the risk of stroke.
• Alcohol and drug abuse: Abusing these substances also increases a person's risk for a stroke.

Stroke symptoms often occur suddenly and without warning. Older adults who experience stroke symptoms or their caregivers should call 911 or go to a hospital emergency department immediately.

Symptoms of stroke, or loss of oxygen and blood flow to the brain, include sudden:

• weakness or numbness in the leg, arm, or face, especially on one side of the body
• confusion or difficulty speaking or understanding
• vision problems in one or both eyes
• dizziness, problems walking, or loss of balance
• severe headache that comes on suddenly and doesn't have another cause
• drowsiness
• nausea or vomiting

In many cases, these warning signs of a stroke occur suddenly and then disappear. If these symptoms go away quickly, they are easy to ignore, but that early resolution does not mean they are not dangerous.

Diagnosis

When making a stroke diagnosis, health care professionals first obtain a complete medical history. A person with stroke symptoms (or a family member or caregiver , if the person cannot communicate) will be asked about his current and previous symptoms, medical problems or surgeries he has had previously, and medications he is taking. A person having stroke symptoms will also be examined and health care professionals will check his reflexes, strength, sensation, and overall coordination. Questions may also be asked to determine whether the patient's memory, speech, or cognition is impaired.

Laboratory tests and procedures may also be helpful when making a stroke diagnosis. To look at the brain, skull, or spinal cord, health care professionals may use computed tomography (CT) scans or magnetic resonance imaging (MRI) scans. Getting a view of the blood vessels that supply the brain may be accomplished by using ultrasound waves to take a picture of the carotid arteries in the neck (this is called a carotid ultrasound or carotid Doppler). Transcranial Doppler or magnetic resonance angiogram may also be used to see the blood vessels in the neck or brain. Another test, called a cerebral arteriogram, uses a catheter inserted in the arm or leg to find any abnormalities of the blood vessels, such as blockages or narrowing.

Other tests, including echocardiograms and electrocardiograms (EKG), may be used to check the heart's function. X-rays, urine samples, and blood oxygen tests may be used to check for infection, and neurologic tests, such as electroencephalogram or nerve conduction tests, may be done if a health care professional suspects a seizure or nerve problem is causing symptoms. Lumbar puncture (LP or spinal tap), the removal of fluid that surrounds the brain and spinal cord, may be used to check for bleeding from a subarachnoid hemorrhage. If doctors think a person has had a stroke, they also usually order blood tests to measure chemicals in the blood, check cholesterol levels, and identify clotting problems that may contribute to stroke.

Treatment

If a person has been diagnosed with a stroke, there are many steps on the road to recovery.

The first stage involves acute care treatment. During this type of treatment, health care professionals work to help the patient survive and prevent another stroke.

People who have had strokes may need to take antiplatelet drugs (such as aspirin , clopidogrel, ticlopidine, and aspirin/dipyridamole) to prevent blood clotting and reduce the risk of recurrent thrombotic stroke. Others may need to take anticoagulants (such as warfarin and heparin) to prevent clot formation.

Sometimes thrombolytic agents are used to treat an ongoing ischemic stroke. If a person having a stroke gets medical treatment within 3 hours of stroke onset, thrombolytic drugs such as recombinant tissue plasminogen activator (rt-PA) can be used to dissolve the blood clot that is blocking blood flow to the brain. Because these drugs can increase bleeding, they should only be used by a doctor who has carefully examined a suspected stroke patient.

Surgical procedures such as carotid endarterectomy may also be performed to reduce the risk of acute or recurrent stroke. In this procedure, surgeons open the carotid artery in the neck and scrape plaque from the artery's walls, thereby reducing the chance that blood clots might lodge in the narrowed artery and cause a stroke.

Devices can also be inserted in the carotid artery to reduce stroke risk. In a procedure called an angioplasty , a small tube called a stent is placed over the artery to help keep it open and reduce the risk of blockage that could cause a stroke. Stents are usually used in people who have had TIAs or who have at least half of their arteries blocked. People who have 80 percent blockage but who have never experienced a stroke might also be advised to have a stent placed.

Stroke treatment also involves recovery and rehabilitation. After acute care, some of the abilities a person has may begin to come back, which is called spontaneous recovery. Spontaneous recovery occurs in the days, weeks, and months following the stroke. Rehabilitation involves helping someone who has had a stroke recover some of the abilities that were lost. Rehabilitation can take place in the hospital, at a recovery facility, or at the patient's home.

Nutrition/Dietetic concerns

Eating a diet that contains too much fat, cholesterol, and sodium (salt) can increase stroke risk. Health care professionals recommend that person who has had a stroke or has stroke risk factors should reduce stroke risk by taking the following steps.

Consume foods lower in fat. Eating a diet filled with saturated fat and cholesterol contributes to atherosclerosis , a factor that increases the risk of stroke. Older adults can cut the fat by choosing low-fat or nonfat dairy items, limiting oil or butter used in cooking, avoiding fried foods in favor of broiled or baked versions, and trimming fat or skin from meats and poultry.

Watch sodium intake. Eating too many high-sodium foods (sodium, or salt, is often used to preserve foods and add flavor) can increase blood pressure and thereby increase the risk of stroke. To cut back on sodium, instead of highly processed foods, choose fresh fruits, vegetables, whole grains, and lean sources of protein. Also, some evidence suggests that adding fiber to the diet might help reduce cholesterol levels. High cholesterol levels are another risk factor for stroke.

Limit alcohol consumption. Research has shown that drinking up to two drinks a day can cut stroke risk in half, but drinking too much does more harm than good. Consuming more than two drinks a day increases stroke risk three-fold. Also, alcohol interacts dangerously with many medicines, so people taking medication should talk to their doctors before consuming any amount of alcohol.

Therapy

Older adults who have experienced a stroke may require a variety of therapies during the rehabilitative process.

Physical therapy, which the National Institute of Neurological Disorders and Stroke calls the “cornerstone of the rehabilitative process,” helps people with stroke relearn balance, movement, and coordination. This type of therapy is essential to help stroke victims learn to walk, sit, stand, and lie down, movements that may be difficult after experiencing a stroke.

Occupational therapy is also often used in post-stroke recovery. With this type of therapy, people who have experienced a stroke relearn how to do activities of daily living, such as eating and drinking, cooking, writing, toileting, and bathing.

For stroke victims who experience speech and language problems, speech therapy can help them understand speech and written words, form words themselves, and develop alternative ways of communicating.

Depression , anxiety , and frustration are a common aspect of the stroke survivor's experience, and psychological counseling can help survivors deal with these problems. Sometimes, cognitive behavioral therapy or medication might be recommended for the survivor to alleviate post-stroke psychiatric problems.

QUESTIONS TO ASK YOUR DOCTOR

• Do I have any of the risk factors for stroke, such as high cholesterol or high blood pressure?
• If I experience any of the warning signs of stroke, what should I do?
• Is there anything I can do now to reduce my risk of stroke?
• I've had TIAs. What can I expect in terms of stroke risk?
• I've survived a stroke. What can I do to improve my recovery and regain function?
• I'm caring for someone who's had a stroke. Can you recommend a support group for me?

Prognosis

People who experience one stroke often go on to have others. According to the National Stroke Association, of the people who have a stroke every year, 5 to 14 percent will have an additional stroke within 1 year. Within 5 years after an initial stroke, 24 percent of women and 42 percent of men will experience recurrent stroke.

In people between 45 and 64, 8 to 12 percent of ischemic strokes and 37 to 38 percent of hemorrhagic strokes cause death within a month.

Prevention

Lowering stroke risk often involves making lifestyle changes, such as sticking to a low-sodium, low-fat diet , to improve circulation and reduce the risk of diseases that can influence stroke risk, such as diabetes, heart disease, high cholesterol, and high blood pressure.

Exercise, especially moderate to high intensity exercise, has also been associated with a lowered risk of stroke. In a large Japanese study of 73,265 men and women, risk of stroke death dropped 29 percent in men and 20 percent in women who got the most intense exercise.

Some older adults might also need to take medication to lower blood pressure and cholesterol, two leading risk factors for stroke. Other adults who are diabetic need to follow their diabetes care plan and control their blood sugar levels carefully, through diet, exercise, and medications.

KEY TERMS

Carotid endarterectomy —Procedure to open the carotid artery in the neck and scrape plaque from the artery's walls, thereby reducing the risk of stroke.

Hemorrhage —Bleeding from the blood vessels.

Ischemia —Blockage of blood flow due to obstruction of the blood vessels.

Stent —A small tube placed within an artery to help keep it open and reduce the risk of blockage that could cause a stroke

Transient ischemic attack (TIA) —Mini strokes that cause symptoms similar to those of a stroke, but which are temporary and disappear.

Caregiver concerns

Caregivers of people who have experienced a stroke will initially want to familiarize themselves with the physical, emotional, and cognitive changes that might occur in the post-stroke recovery period. Stroke victims may experience memory loss , confused behavior or poor judgment, depression, unpredictable or inappropriate emotions (a condition sometimes called involuntary emotional expression disorder), communication problems, problems dressing and grooming themselves and caring for their skin, problems eating, and pain .

To help prevent confusion in the stroke survivor, a caregiver needs to ensure that the survivor's environment is orderly and easy to navigate. If the stroke victim is having trouble dressing or feeding himself or herself, talk to the person's health care provider or stroke rehabilitation specialist about adaptive aids that may make independent living easier.

To deal with the emotional changes and depressive symptoms that often accompany the post-stroke recovery period, stroke victims might need behavioral therapy, antidepressant medications, or a combination of both.

Communication problems or difficulty with speech (referred to as aphasia) often occur after stroke because of damage to the areas of the brain that control communication. Caregivers might need to secure professional help to cope with these difficulties.

When caring for someone with a stroke, proper skin care is important, especially for survivors who spend lots of time sitting or in wheelchairs. Caregivers can help prevent bed sores by making sure the person changes position frequently and has pillows or other soft props to support disabled limbs.

Caring for a person who has had a stroke can be frightening, confusing, and frustrating for family members. To get emotional support in the post-stroke journey, caregivers can attend support groups for stroke victims and their families.

organizations

American Heart Association/American Stroke Association, 7272 Greenville Avenue, Dallas, TX, 75231, 800-AHA-USA-1 (242-8721), http://www.americanheart.org; http://www.strokeassociation.org.

National Institute of Neurological Disorders and Stroke, P. O. Box 5801, Bethesda, MD, 20824, 301-496-5751, 800-352-9424, braininfo@ninds.nih.gov, http://www.ninds.nih.gov.

National Stroke Association, 9707 E. Easter Lane Building B, Centennial, CO, 80112, 800-787-6537, 303-649 1328, info@stroke.org, http://www.stroke.org.

Rehabilitation Institute of Chicago, 345 E. Superior Street, First Floor, Chicago, IL, 60611, 312-238-5433, 312-238-2860, lifecenter@ric.org, http://lifecenter.ric.org.

Stroke Association UK, Stroke House, 240 City Road, London, United Kingdom, EC1V 2PR, 020 7566 0300, info@stroke.org.uk, http://www.stroke.org.uk.

Amy Sutton

Stroke

Definition

Description

Causes and symptoms

Demographics

Diagnosis

Treatment

Prognosis

Prevention

Resources

Definition

A stroke, also called a cerebral vascular accident (CVA), is the sudden death of cells in a specific area of the brain due to inadequate blood flow.

Description

A stroke occurs when blood flow is interrupted to a part of the brain, either when an artery bursts or becomes closed when a blood clot lodges in it. Blood circulation to the area of the brain served by that artery stops at the point of disturbance, and the brain tissue beyond that is damaged or dies. (Brain cells need blood to supply oxygen and nutrients and to remove waste products.) Depending on the region of the brain affected, a stroke can cause paralysis, loss of vision, speech impairment, memory loss and reasoning ability, coma, or death. The effects of a stroke are determined by how much damage occurs, and which portion of the brain is affected.

About a third of all strokes are preceded by transient ischemic attacks (TIAs), or mini-strokes, that temporarily interrupt blood flow to the brain. While TIAs cause similar symptoms (such as sudden vision loss or temporary weakness in a limb), they abate much more quickly than full-fledged strokes, usually within a few hours—sometimes as quickly as a few minutes.

Stroke is a medical emergency requiring immediate treatment. Prompt treatment improves the chances of survival and increases the degree of recovery that may be expected. A person who may have suffered a stroke should be seen in a hospital emergency room without delay. Treatment to break up a blood clot, the major cause of stroke, must begin within three hours of the stroke to be most effective. Improved medical treatment of all types of stroke has resulted in a dramatic decline in death rates in recent decades. In 1950 nine in ten stroke victims died, compared to slightly less than one in three today.

Causes and symptoms

Causes

There are four main types of stroke: cerebral thrombosis, cerebral embolism, subarachnoid hemorrhage, and intracerebral hemorrhage. Cerebral thrombosis and cerebral embolism, known as ischemic strokes,

are caused by blood clots that block an artery supplying the brain, either in the brain itself or in the neck. They account for 70–80% of all strokes. Subarachnoid hemorrhage and intracerebral hemorrhage are hemorrhagic strokes that occur when a blood vessel bursts around or in the brain, either from trauma or excess internal pressure. Hypertension (high blood pressure) and atherosclerosis are usually contributing factors in these types of strokes.

CEREBRAL THROMBOSIS

Cerebral thrombosis, the most common type of stroke, occurs when a blood clot, or thrombus, forms within the brain itself, blocking blood flow through the affected vessel. This is usually due to atherosclerosis (hardening) of brain arteries, caused by a buildup of fatty deposits inside the blood vessels. Cerebral thrombosis occurs most often at night or early in the morning, and is often preceded by a TIA. Recognizing the occurrence of a TIA, and seeking immediate treatment, is an important step in stroke prevention.

CEREBRAL EMBOLISM

Cerebral embolism occurs when a blood clot from elsewhere in the circulatory system breaks free. If it becomes lodged in an artery supplying the brain, either in the brain or in the neck, it can cause a stroke. The most common cause of cerebral embolism is atrial fibrillation, which occurs when the upper chambers (atria) of the heart beat weakly and rapidly, instead of slowly and steadily. Blood within the atria does not empty completely, and may form clots that can then break off and enter the circulation. Atrial fibrillation is a factor in about 15% of all strokes, but this risk can be dramatically reduced with daily use of anticoagulant medication (such as Hepa-rin or Coumadin).

SUBARACHNOID HEMORRHAGE

In this type of stroke, blood spills into the subarachnoid space between the brain and cranium. As fluid builds up, pressure on the brain increases, impairing its function. Hypertension is a frequent cause of these types of stroke, but vessels with preexisting defects, such as an aneurysm, are also at risk for rupture. Aneurysms are most likely to burst when blood pressure is highest, and controlling blood pressure is an important preventive strategy. Subarachnoid hemorrhages account for about 7% of all strokes.

INTRACEREBRAL HEMORRHAGE

Representing about 10% of all strokes, intracerebral hemorrhage affects vessels and tissue within the brain itself. As with subarachnoid hemorrhage, bleeding deprives affected tissues of blood supply, and the accumulation of fluid within the inflexible skull creates pressure on the brain that can quickly become fatal. Despite this, recovery may be more complete for a person who survives hemorrhage than for one who survives a clot, because the effects of blood deprivation are usually not as severe.

Risk factors

Risk factors for stroke involve:

• Age and sex—the risk of stroke increases with age, doubling for each decade after age 55. Men are more likely to have a stroke than women.
• Heredity—People with a family history of stroke have an increased risk of stroke themselves. In addition, African-Americans, Asians, and Hispanics all have higher rates of stroke than whites, related partly to higher blood pressure.
• Diseases—People with diabetes, heart disease (especially atrial fibrillation), high blood pressure, or prior stroke are at greater risk for stroke. Patients with one or more TIAs have ten times the risk.
• Other medical conditions—Stroke risk increases with obesity, high blood cholesterol, or high red blood cell count.
• Lifestyle choices—Stroke risk increases with cigarette smoking (especially if combined with the use of oral contraceptives), a sedentary lifestyle, alcohol consumption above two drinks per day, and/or the use of cocaine or intravenous drugs.

Symptoms

Knowing the symptoms of stroke is as important as knowing those of a heart attack. Patients with stroke symptoms should seek emergency treatment without delay, which may mean dialing 911 rather than their family physician. Specific symptoms of a stroke depend on the type, but all types share some characteristics in common.

An embolic stroke usually comes on quite suddenly and is intense right from the start, while symptoms of a thrombotic stroke come on more gradually. Symptoms for these ischemic strokes may include:

• blurring or decreased vision in one or both eyes
• severe headache, often described as “the worst headache of my life”
• weakness, numbness, or paralysis of the face, arm, or leg, usually confined to one side of the body
• dizziness, loss of balance or coordination, especially when combined with other symptoms

Hemorrhagic strokes are somewhat different. An intracranial hemorrhage exhibits any or all of the following symptoms:

• loss of consciousness
• altered mental state
• seizure
• vomiting or severe nausea
• extreme hypertension
• weakness, numbness, or paralysis, especially on one side of the body
• sudden, severe headache

Symptoms of a subarachnoid hemorrhage include:

• severe headache that begins suddenly
• nausea or vomiting
• stiff neck
• light intolerance
• loss of consciousness

Demographics

Each year, more than half a million people in the United States have a stroke. It is the third leading cause of death, killing about a third of its victims— approximately 150,000 Americans each year. For those that survive, stroke is the leading cause of disability. Two-thirds of all strokes occur in people over age 65, with men more affected than women, although women are more likely to die from a stroke. African-Americans suffer strokes more often than whites, and are more likely to be die from them as well. This may be because African-Americans tend to suffer from hypertension more frequently than other groups.

Diagnosis

Diagnosing a stroke begins with a careful medical history, especially concerning the onset and distribution of symptoms, presence of risk factors; in this way other possible causes are excluded. A brief neurological exam is performed to identify the degree and location of any deficits, such as weakness, lack of coordination, or vision loss.

Once stroke is suspected, imaging technology is used to determine what type the patient has suffered—a critical distinction that guides therapy. A non-contrast computed tomography scan (CT scan) can reliably identify hemorrhagic strokes, caused by uncontrolled bleeding in the brain. Magnetic resonance imaging (MRI), on the other hand, particularly diffusion-weighted imaging, can detect ischemic strokes, caused by blood clots, earlier and more reliably than CT scanning.

Blood and urine tests are also run to look for possible abnormalities. Other investigations that may be performed to guide treatment include electrocardiogram, angiography, ultrasound, and electroencephalogram.

Treatment

When brain cells die during a stroke, they release toxic chemicals that can trigger a chain reaction that can injure or kill other nearby cells. Damage from stroke may be significantly reduced by emergency treatment, and is a significant factor in how fully a patient will recover.

Emergency treatment

Emergency treatment of an ischemic stroke attempts to dissolve the clot. This “thrombolytic therapy” is performed most often with tissue plasminogen activator (t-PA), which must be administered within three hours of the stroke event. (Patients who awaken with stroke symptoms are ineligible for this type of therapy, since the time of onset cannot be reliably determined.) t-PA therapy has been shown to improve recovery and decrease long-term disability in patients. It carries a 6.4% risk of inducing a cerebral hemorrhage, however, and is not appropriate for patients with bleeding disorders, very high blood pressure, known aneurysms, any evidence of intracranial hemorrhage, or incidence of stroke, head trauma, or intracranial surgery within the past three months. Patients with clot-related stroke who are ineligible for t-PA treatment may be treated with heparin or other blood thinners, or with aspirin or other anticlotting agents in some cases.

Emergency treatment of hemorrhagic stroke is aimed at controlling intracranial pressure that accompanies these types of strokes. New surgical techniques can effectively relieve the pressure, especially when begun soon after the stroke event occurs. Surgery for hemorrhage due to aneurysm may be performed if the aneurysm is close enough to the cranial surface to allow access. Ruptured vessels are closed off to prevent rebleeding. For aneurysms that are difficult to reach surgically, endovascular treatment, in which a catheter is guided from a larger artery up into the brain to reach the aneurysm, may be effective. Small coils of wire are discharged into the aneurysm, which plug it up and block off blood flow from the main artery.

Rehabilitation

Rehabilitation refers to a comprehensive program designed to regain as much function as possible and compensate for permanent losses. Approximately 10% of stroke survivors are without any significant disability and able to function independently. Another 10% are so severely affected that they must remain institutionalized for severe disability. The remaining

80% can return home with appropriate therapy, training, support, and care.

Rehabilitation is coordinated by a team of medical professionals and may include the services of a neurologist, a physician who specializes in rehabilitation medicine, a physical therapist, an occupational therapist, a speech-language pathologist, a nutritionist, a mental health professional, and a social worker. Rehabilitation services may be provided in an acute care hospital, rehabilitation hospital, long-term care facility, outpatient clinic, or at home.

The rehabilitation program is based on the patient’s individual deficits and strengths. Strokes on the left side of the brain primarily affect the right half of the body, and vice versa. In addition, in left brain-dominant people, who constitute a significant majority of the population, left-brain strokes usually lead to speech and language deficits, while right-brain strokes may affect spatial perception. Patients with right-brain strokes may also deny their illness, neglect the affected side of their body, and behave impulsively.

Rehabilitation may be complicated by cognitive losses, including diminished ability to understand and follow directions. Poor results are more likely in patients whose strokes left them with significant or prolonged cognitive changes, sensory losses, language deficits, or incontinence.

PREVENTING COMPLICATIONS

Rehabilitation begins with prevention of medical complications, including stroke recurrence, using many of the same measures used to prevent stroke, such as smoking cessation and getting hypertension under control.

One of the most common medical complications following stroke is deep venous thrombosis, in which a clot forms within a limb immobilized by paralysis. Clots can also become lodged in an artery feeding the lungs, a condition called pulmonary embolism, that is a common cause of death in the weeks following a stroke. Resuming activity within a day or two after the stroke is an important preventive measure, along with use of elastic stockings on the lower limbs. Drugs that prevent clotting may also be given, including intravenous heparin and oral warfarin.

Weakness and loss of coordination of the swallowing muscles may impair swallowing (dysphagia), and allow food to enter the lower airway. This may lead to aspiration pneumonia, another common cause of death shortly after a stroke. Dysphagia may be treated with retraining exercises and temporary use of pureed foods.

Other medical complications include urinary tract infections, pressure ulcers, falls, and seizures. Not surprisingly, depression occurs in 30–60% of stroke patients; its severity is usually related to the level of permanent functional impairment It can be treated with antidepressants and psychotherapy.

TYPES OF REHABILITATIVE THERAPY

Brain tissue that dies in a stroke cannot regenerate. In some cases, however, rehabilitation training can help other brain regions perform the same functions of that tissue. In other cases, compensatory actions may be developed to replace lost abilities.

Physical therapy is used to maintain and restore range of motion and strength in affected limbs, and to maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for instance). The physical therapist advises patients on mobility aids such as wheelchairs, braces, and canes. In the recovery period, a stroke patient may develop muscle spasticity and contractures (abnormal muscle contractions) that can be treated with a combination of stretching and splinting.

Occupational therapy improves self-care skills such as feeding, bathing, and dressing, and helps develop effective compensatory strategies and devices for activities of daily living. A speech-language pathologist focuses on communication and swallowing skills. When dysphagia is a problem, a nutritionist can advise alternative meals that provide adequate nutrition.

Psychological therapy can help treat depression or loss of thinking (cognitive) skills. A social worker may help coordinate services and ease the transition out of the hospital back into the home. Both social workers and mental health professionals help counsel the patient and family during the difficult rehabilitation period. Caring for a person affected with stroke requires a new set of skills and adaptation to new demands and limitations. Home caregivers may develop stress, anxiety, and depression—caring for the caregiver is an important part of the overall stroke treatment program. Support groups can provide an important source of information, advice, and comfort for stroke patients and caregivers; joining one can be an important step in the rehabilitation process.

Prognosis

Stroke is fatal for about 27% of white males, 52% of African-American males, 23% of white females, and 40% of African-American females. Stroke survivors may be left with significant deficits. Emergency

KEY TERMS

Aneurysm —A symptomless bulging of a weak arterial wall that can rupture, leading to stroke.

Angiography —A procedure in which a contrast medium is injected into the bloodstream (through an artery in the neck) and its progress through the brain is tracked. This illustrates where a blockage or hemorrhage has occurred.

Anticoagulant —A medication (such as warfarin, Coumadin, or Heparin) that decreases the blood’s clotting ability preventing the formation of new clots. Although anticoagulants will not dissolve existing clots, they can stop them from getting larger. These drugs are commonly called blood thinners.

Atrial fibrillation —A disorder in which the upper chambers (atria) of the heart do not completely empty with each contraction (heartbeat). This can allow blood clots to form and is associated with a higher risk of stroke.

Electrocardiogram —(EKG) A test that measures the electrical activity of the heart as it beats. An abnormal EKG can indicate possible cardiac disease.

Electroencephalogram —(EEG) A test that measures the electrical activity of the brain by means of electrodes placed on the scalp or on or in the brain itself. It may be used to determine whether or not a stroke victim has had a seizure.

Hypertension —High blood pressure, often brought on by smoking, obesity, or other causes; one of the major causes of strokes.

Pressure ulcers —Also known as pressure sores or bed sores, these can develop in stroke patients who are unable to move. If not treated properly, they can become infected.

Tissue plasminogen activator (tPA) —A drug that is sometimes given to patients within three hours of a stroke to dissolve blood clots within the brain; also used to treat heart attack victims.

Ultrasound —A noninvasive test in which high-frequency sound waves are reflected off a patient’s internal organs allowing them to be viewed. In stroke victims, a cardiac ultrasound, or echocardiogram, allows the beating heart to be examined.

treatment and comprehensive rehabilitation can significantly improve both survival and recovery.

Prevention

The risk of stroke can be reduced through lifestyle changes:

• stop smoking
• control blood pressure
• get regular exercise
• maintain a healthy weight
• avoid excessive alcohol consumption
• get regular checkups and follow the doctor’s advice regarding diet and medicines

Use of high-estrogen dose oral contraceptives increase the chances for developing stroke, particularly in women who smoke and/or who are over 35. Currently, there are low-estrogen dose oral contraceptives, for which a clear relationship with stroke development is unclear.

Treatment of atrial fibrillation may also significantly reduce the risk of stroke. Preventive anticoagulant therapy may benefit those with untreated atrial fibrillation. Warfarin (Coumadin) has proven to be more effective than aspirin for those with higher risk.

Screening for aneurysms may be an effective preventive measure in those with a family history of aneurysms or autosomal polycystic kidney disease, which tends to be associated with aneurysms.

Resources

BOOKS

Caplan, L. R., M. L. Dyken, and J. D. Easton. American Heart Association Family Guide to Stroke Treatment, Recovery, and Prevention. New York: Times Books, 1996.

Duthie, Edmund H., Jr. Practice of Geriatrics. 3rd Edition. Philadelphia: W. B. Saunders, 1998: 328-335.

Goetz, Christopher G., and others. Textbook of Clinical Neurology. 1st edition. Philadelphia: W. B. Saunders, 1999: 909-911.

Warlow, C. P., and others. Stroke: A Practical Guide to Management. Boston: Blackwell Science, 1996.

PERIODICALS

Krishnan, K. Ranga Rama. “Depression as a contributing factor in cerebrovascular disease.” American Heart Journal (October 2000).

ORGANIZATIONS

American Heart Association and American Stroke Association. 7272 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org

National Stroke Association. 9707 E. Easter Lane, Engle-wood, Co. 80112. (800) 787-6537. http://www.stroke.org

Laith Farid Gulli, M.D.
Bilal Nasser, M.D.