Stroke: Causes, Symptoms, Treatment, and Prevention

Spread the love

Hemorrhagic stroke is less common but more severe than ischemic stroke. It occurs when a weakened blood vessel ruptures. The two types of weakened blood vessels that usually cause hemorrhagic stroke are aneurysms and arteriovenous malformations (AVMs). Aneurysms are sack-like out-pouchings of blood vessels that are caused by weakening of the vessel wall. They can develop over a long period of time and go unnoticed. High blood pressure and age are the most common causes of aneurysms. AVMs are tangles of abnormal blood vessels. The cause of AVMs is unknown. Like aneurysms, it is possible for AVMs to go unnoticed and to cause no symptoms until they rupture. The bleeding from a hemorrhagic stroke accumulates over a period of minutes to hours and increases the pressure on the brain. This can cause headache, nausea, vomiting, lethargy, loss of consciousness, and death.

There are two broad categories of stroke: ischemic and hemorrhagic. The most common type of stroke, ischemic stroke, occurs when an artery to the brain is blocked. The blockage reduces the blood flow to the brain. This can occur in two ways. In thrombotic stroke, a blood clot forms in the arteries that supply blood to the brain. The clot most often forms in areas damaged by atherosclerosis. If the clot is large, it will cause a severe blockage of the brain’s blood supply and produce symptoms of stroke. The formation of the clot is preceded by the occurrence of a transient ischemic attack (TIA) in one third of patients. A TIA is a temporary episode of neurological dysfunction caused by a brief lack of blood flow to the brain. The second way that an ischemic stroke can occur is when a clot forms in the heart or in a major blood vessel and travels to the brain. This is called cerebral embolism. The symptoms of ischemic stroke usually develop over hours or a day or two, making it possible to receive medical attention before the stroke is fully developed. High blood pressure is the most important risk factor for ischemic stroke.

A stroke, which is also known as cerebrovascular accident (CVA), is the term used to describe the sudden death of brain cells in a localized area due to inadequate blood flow. Inadequate blood flow is caused by blockage of a blood vessel from a clot or narrowing of the vessel. Hemorrhage in the brain from a ruptured blood vessel also causes stroke. In all, the part of the brain that is served by the damaged blood vessel is affected. Stroke can cause neurological abnormalities or death. Approximately 750,000 persons in the United States suffer from stroke each year; it is the third leading cause of death and the leading cause of long-term disability. Stroke has been recognized for several thousand years; ancient Egyptians and Greeks noted paralysis and other features of stroke. The incidence of stroke in the United States has declined slightly, because of better control of known risk factors. However, the actual number of deaths and severe disability caused by stroke continues to increase because the population is aging.

What is a stroke?

A stroke is a serious medical condition in which the blood supply to part of the brain is interrupted or severely reduced, depriving brain tissue of oxygen and food. This can cause brain cells to die within minutes. This can affect the body in different ways. It can affect movement, speech, the senses (taste, touch, smell, vision, and hearing) and can cause other effects on the body, often depending on which part of the brain is affected. Some effects of stroke can be permanent, but a person’s function can also improve. The brain is an extremely complex organ that controls various body functions. If a stroke occurs in a specific part of the brain, it may result in the inability to move an arm or leg on one side of the body, inability to understand spoken language, or the inability to speak. There are 2 main types of stroke. An ischemic stroke is the most common, accounting for about 85% of all strokes. It is caused by a blockage of the blood supply to the brain, and there are a few different ways this can happen. The second type of stroke is a hemorrhagic stroke. This is caused by bleeding in or around the brain. This occurs when a weakened blood vessel supplying the brain bursts and causes the blood to leak into the brain.

Types of strokes

The two major types of stroke are termed ischemic and hemorrhagic. An ischemic stroke is caused by a blockage of blood flow to the brain, resulting in cell death at the site of the blockage due to a lack of oxygen. About 80% of all strokes are of this nature. There are two types of ischemic blockage: embolic, in which an embolus travels from another site in the circulatory system to block a smaller artery; and thrombotic, in which an atheromatous plaque on a larger artery ruptures, resulting in the formation of a blood clot at the site, which can then travel to and block a smaller artery. The blood clot and the site of formation together are referred to as a thrombus. Hemorrhagic strokes occur when a blood vessel in the brain bursts, again resulting in cell death due to a lack of oxygen. The blood from the ruptured vessel then accumulates in surrounding tissues and forms a hematoma. There are two types of hemorrhagic stroke: intracerebral, in which the blood from the ruptured vessel causes injury to the cells in the tissues surrounding the vessel; and subarachnoid, in which the blood accumulates over the surface of the brain. Focal cerebral ischemia involves a continuum of reversible to irreversible injury. An understanding of these processes is essential for the development of effective therapies for acute stroke.

Risk factors for stroke

Modifiable risk factors for stroke are those risk factors that are largely lifestyle-based and can be changed with the person’s actions. High blood pressure is the single most important modifiable risk factor for stroke. If you have high blood pressure, your risk of stroke is four times higher than someone with normal blood pressure. High blood pressure damages the arteries and makes them more likely to become blocked or burst. It can also cause aneurysms in the brain. Food high in salt will increase blood pressure, so recently there has been a push to consume less salt to help reduce blood pressure levels. High cholesterol is a risk factor because it affects the blood vessels. Cholesterol is a fatty substance that is carried in the blood and the two main types are LDL cholesterol and HDL cholesterol. High levels of LDL cholesterol in the blood cause the buildup of fatty deposits on the artery walls which will narrow the arteries and increase the risk of blockage or a blood clot. A high level of LDL cholesterol is controlled by eating food low in saturated fat, trans fat, and cholesterol and it’s recommended some people take medication known as statins. HDL cholesterol is beneficial to the body and low levels of HDL cholesterol can increase the risk of stroke. Diabetes increases a person’s risk of stroke and reduces life expectancy. This is because diabetes affects the blood vessels causing them to narrow and increase the chance of clot formation. There are two types of diabetes, and type 2 diabetes can often be prevented by maintaining a healthy lifestyle. Atrial fibrillation (AF) is a heart condition that causes an irregular heartbeat and can cause clots to form in the heart. If a clot travels from the heart to the brain, it can cause a stroke. High-dose aspirin and warfarin are effective treatments to prevent stroke in people with AF.

Signs and Symptoms

Difficulty speaking or understanding Often times, strokes can cause difficulty speaking and understanding. A person having a stroke may experience confusion and have a hard time following along with written or spoken language. They may not understand what is being said to them and are not able to formulate a proper response. What they are saying may not make much sense and can be slurred. In some cases, a person may experience complete loss of speech. This is frightening to the person as they may not understand what is happening to them.

Sudden numbness or weakness When you have a stroke, it can affect any number of systems including motor and sensory. Sudden numbness or weakness of the face, arm or leg, especially on one side of the body is typical. This can range from a mild weakness to a complete paralysis of one side of the body. One way to test this is to ask the person to smile. If the smile is uneven or droopy, this may be a sign of stroke. Also, asking the person to hold both arms up. If one arm drifts downward, this could be a sign of stroke.

Sudden numbness or weakness

The symptoms reflect the region of the brain where the stroke has occurred or where the blood supply has been blocked off. In general, the right side of the brain controls the left side of the body, and the left side of the brain controls the right side of the body. Often, it is the left side of the brain that is affected, and this tends to cause problems with movement on the right side of the body or in the muscles of the mouth and face. A spinal cord stroke causes weakness and numbness in the legs and trunk and can lead to paraplegia or quadriplegia. If the symptoms last for more than a few seconds, it can be assumed that brain tissue has been damaged. However, in the case of a minor stroke, the damage may be so small and so deep inside the brain that only a minimum amount of weakness occurs, and it may be difficult to notice.

Sudden numbness or weakness of the face, arm or leg, especially on one side of the body, is one of the most common symptoms of a stroke. It is generally described as a feeling of “dead weight” in the limbs and is so sudden in onset that the victim may awaken with it or notice it on arising. Often, the person affected is unable to move the affected limb and may be totally or partially paralyzed. Sometimes, the weakness is not noticed by the person it is happening to, but is identified by someone else. For example, the victim may only have weakness of the muscles of the mouth, and this would be apparent only due to slurring of the speech.

Difficulty speaking or understanding

Aphasia is a very frustrating disorder. Imagine a time when you had something important to say but could not find the word to express it. That feeling of frustration is what many stroke patients with aphasia experience on a daily basis. There are several types of aphasia, and the symptoms vary from one person to another. Someone with global aphasia may understand very little or no spoken language and may not be able to speak or write. People with Broca’s aphasia can understand others but cannot express themselves through speech or writing. They often speak in very short sentences and omit words. Wernicke’s aphasia is characterized by fluent, seemingly well-articulated speech. However, the words may be complete jumbles and are not understood by the speaker or the listener. Finally, someone with anomic aphasia has trouble finding words. This may be the least severe type of aphasia, but it can still be very frustrating.

A stroke can cause one of several communication disorders. A person who has had a stroke may develop aphasia, a disorder that limits the ability to speak and write. A stroke can also lead to the development of apraxia, a disorder characterized by the inability to carry out learned purposeful movements, such as using a fork or combing one’s hair, even though the physical abilities are there. The patient knows what he wants to do, but cannot. Apraxia can also affect the ability to speak. Finally, a stroke can cause dysarthria, a weakness or paralysis of the muscles involved in speaking. This weakness can cause slow, effortful speech that is difficult to understand. Many stroke patients are unaware of these disorders because they may not realize the effect the stroke has had on their communication abilities.

Vision problems

Often times after a stroke, particularly those who have suffered from a cerebral stroke, a patient may have difficulty recognizing what he/she is seeing. This failure to understand incoming visual information is termed agnosia. A stroke can also cause double vision or blurred vision. If a stroke damages only one side of the brain, the patient’s vision problems will be on the same side of the body. For example, if a stroke affects the right side of the brain, the vision loss or abnormality will be experienced in the right eye. Finally, a stroke can cause a loss of visual field. This means that the patient can see only one half of the visual world to one side of the body. For example, there may be normal vision on the right side of the body, but the left side of the body gives no visual information or gives information that is confused. This can be very disabling and the patient may not be aware that it is happening.

Severe headache

A sudden, severe headache is a telltale symptom of a stroke. Such a headache might come on with no warning, and is usually different from other headaches because it is so severe. A headache resulting from a stroke can be accompanied by a variety of other symptoms or the headache can be the sole symptom of a stroke. The headache associated with a stroke usually builds in intensity over minutes to hours and is located on one side of the head. The headache can be of several different descriptions, the most typical is a sudden onset of a severe headache, often described as “the worst headache I’ve ever had” with a throbbing pain. This is a similar description to that of a hemorrhagic stroke, which is the result of bleeding in the brain. However, a severe headache can also be a symptom of an ischemic stroke (resulting from a lack of blood flow to the brain), particularly a stroke in the brainstem. Other descriptions of stroke-induced headaches include sudden onset of a sharp pain in the neck and upper back of the head which can be associated with a vertebral or basilar artery stroke. Finally, the headache can be accompanied by facial pain, pain between the eyes, and pain behind one eye. This is usually a symptom of a stroke in the anterior cerebral artery.

Treatment and Rehabilitation

Some of the things done in aid of the stroke patient are entirely for the benefit of the person who is unable to do anything for their own recovery. Bed rest is one such thing. The patient should not be worried at having to stay in bed for a length of time. The greatest recovery usually takes place in the first few months after the stroke and so it is important to make the right preparations to maximize the chance of recovery. Giving up the thought of ever walking again is a stupid thing to do. Electrophysiological studies have shown that the muscles in the paralyzed limb never lose their potential for movement. It is of the utmost importance to keep these muscle power potentials alive. If movement is lost from a joint, muscle becomes soft and shortened and after a time it becomes impossible to straighten the limb. When a limb is positioned with its muscle on stretch, that muscle will retain functional potential. Softened muscles in the subluxed limb are not desired for movement. Ideal physiotherapy for stroke paralysis should set out to prevent subluxation.

Emergency treatment for stroke

Emergency treatment begins with checking the vital signs of the person suffering a stroke. The airway must be open and, if necessary, the person should be artificially ventilated. Oxygen can be given if available. Blood pressure should be measured and if it is raised, only a stroke unit can give appropriate treatment so the person would need transferring there. The glucose concentration is checked and hypoglycemia corrected. An IV access will be needed so that the person can be given fluids and medication. The next step is to determine if the stroke is due to a blood clot (ischemic) or a burst blood vessel (hemorrhagic). This is vital as giving antiplatelet medication (e.g. aspirin) to someone with a hemorrhagic stroke would worsen the situation. On the other hand, not giving aspirin in the first 48 hours after an ischemic stroke is considered to be harmful. The most effective treatment for a person suffering an ischemic stroke is drug therapy using a thrombolytic drug. This drug works by dissolving the clot and so must be given ASAP after the onset of a stroke. However, it can only be used on a small percentage of people suffering a stroke, approximately 1-4% of them. This is because the drug must be given within 0-4 hours of a stroke with a CT scan being taken beforehand to make sure that the person does not have a hemorrhagic stroke and that the stroke is not severe. Other forms of treatment for ischemic stroke include aspirin and blood pressure management, and care to prevent and treat complications such as chest pain and infection. Unfortunately, there is no drug treatment at present for hemorrhagic stroke and so therapy involves the general medical treatment of the patient, treating any complications, reduction of blood pressure and specialized neurosurgical intervention only in rare instances. An emergency CT scan will determine the most appropriate treatment. Despite the advances that have been made in treating stroke, there is still only a limited time frame in which any treatment can be started and healthcare facilities are not always well equipped to deal with emergency stroke patients.

Medications for stroke

Medications to treat acute stroke: – Clot-busting drugs: The most common medication for acute ischemic stroke is tissue plasminogen activator (tPA). tPA is given through an intravenous (IV) line to dissolve blood clots and improve blood flow to the part of the brain being deprived of blood. tPA must be given within 4.5 hours of the onset of stroke symptoms, and the sooner it is given, the better. Too much delay makes the drug more likely to cause bleeding in the brain, which can be life-threatening. Therefore, it is crucial that anyone having stroke symptoms get to a hospital as quickly as possible. – An alternative treatment for acute ischemic stroke is intra-arterial thrombolysis, a newer procedure in which the tPA is delivered directly at the clot through a catheter. Intra-arterial thrombolysis has a longer time window than IV tPA, but it is still recommended as quickly as possible after stroke onset.

Medicines are used to treat stroke as soon as possible after the event to improve the chances of survival and recovery, and to prevent further strokes. Medicines are effective for certain strokes, such as ischemic strokes, but less so for others. The type of medication a doctor prescribes will depend on the type of stroke and the patient’s medical history.

Rehabilitation after a stroke

A rehabilitation program designed with input from the person who has suffered a stroke and their family is a very important part of recovery. The impact of a stroke varies from person to person because every stroke is different but, in general terms, the more severe the stroke, the more help will be needed to make a good recovery. The first stage of rehabilitation can begin when the person is still in the hospital. The main focus at this stage is to make sure the person is medically stable and to prevent complications from the stroke. Depending on the severity of the stroke, problems such as limb weakness, loss of bladder or bowel control, and difficulty with speaking or swallowing may need special attention. A rehabilitation team, which may involve the doctor, a nurse, a physiotherapist, an occupational therapist, and a speech therapist, will assess the person’s needs and plan appropriate treatment. Many strokes cause weakness or paralysis on one side of the body. Physiotherapy will mainly be aimed at improving mobility. This may involve specific exercises to improve strength, balance, and coordination. Physiotherapists can also help to improve the person’s ability to perform everyday tasks by teaching them how to conserve energy, for example, by only using one hand for a two-handed task or by teaching them a different way of carrying out the task.

Preventing future strokes

Finally, diabetics can reduce the risk of a recurrent stroke by effectively managing their condition.

Healthy lifestyle: Maintaining a healthy lifestyle involving a balanced diet, regular exercise, limiting alcohol intake, and avoiding illegal drugs is advantageous in that it can reduce the risk of stroke. People will also be healthier, thus reducing the incidence and severity of other stroke risk factors.

High cholesterol: The presence of high cholesterol in the blood can contribute to the thickening of the arteries, thus increasing the risk of stroke. By lowering the cholesterol content in the blood, it is possible to reduce the risk of stroke.

Monitoring atrial fibrillation: Atrial fibrillation is an abnormal heart rhythm that can increase the risk of stroke. The main cause of atrial fibrillation is high blood pressure and excessive alcohol intake. Those who suffer from atrial fibrillation may be given blood-thinning medication such as warfarin to reduce the risk of stroke.

Controlling high blood pressure: High blood pressure is the number one risk factor for strokes. If blood pressure is lowered, it can reduce the risk of further strokes by 35-40%. The recommended blood pressure is usually 120/80. However, those who have had a stroke, or for those with diabetes or kidney disease should aim to have it lower than 130/80. The ways of lowering blood pressure are to lose weight, engage in regular exercise, maintain a healthy diet, limit alcohol intake, reduce stress, and if necessary, take medication.

Preventing future strokes: It is unfortunate that once a person has encountered a stroke, they are at a higher risk of having another. However, there are many things that can be done to prevent a recurrent stroke.

Prevention and Lifestyle Changes

High-fat dairy products are the main target in the DASH diet as they are major sources of saturated fat. Studies have shown that high-fat dairy products are also linked to an increased risk of ischemic stroke. The Mediterranean diet is proven to lower the risk of heart disease and stroke as it is rich in fruits, vegetables, whole grains, and includes olive oil and fish but limited red and processed meats.

Recurrent stroke patients with high cholesterol levels who changed their eating habits and added exercise to their daily routine were able to reduce their risk of another stroke by 35-40% according to a clinical trial done with over 4000 participants. This trial lasted five years and was conducted in 45 different clinics in the U.S, Canada, and Scotland and has proven that a healthy diet and exercise can greatly reduce the risk of a stroke. Highly recommended diets for stroke prevention and general public health are the DASH (Dietary Approaches to Stop Hypertension) diet and the Mediterranean diet. More information on these diets can be found on the National Heart, Lung, and Blood Institute website.

There are several important lifestyle changes to make to aid in the prevention of a stroke. Many of us have a busy, work-driven lifestyle which may have caused us to dismiss the importance of a healthy diet. Fast food and frozen meals may be convenient, but they are often high in trans and saturated fats which have been proven to increase the risk of heart disease and diabetes as well as cause obesity. It is uncertain if a high-fat diet alone can lead to a stroke, but it has been proven to be a huge contributing factor to many other conditions that can cause a stroke, therefore reducing your fat intake is a wise decision.

A study done in nine different countries and published in the Lancet Medical Journal stated that 90 percent of strokes are due to 10 risk factors that can be controlled such as high blood pressure, smoking, and diabetes. Other factors such as diet and exercise, alcohol consumption, and stress are lifestyle choices that can greatly affect the risks of having a stroke. Therefore, it is important to make lifestyle changes to aid in the prevention of strokes.

Healthy diet and exercise

Eating healthy and being physically active can reduce your risk of getting a stroke. It can also help you lose weight and lower your risk of developing other health problems. A healthy diet is one of the main factors that can help you to prevent a stroke. You should eat a balanced diet that includes five portions of fruit and vegetables a day, plenty of starchy foods such as wholegrain bread, pasta and rice, and eat fish twice a week – one being an oily fish. Cut down on foods containing a lot of fat and sugar. Too much fat can increase your weight and raise your cholesterol levels, which can in turn increase the risk of a stroke or heart attack. Try to replace saturated fats such as butter, lard and cheese with unsaturated fats that are healthier, found in oils and spreads, oily fish and avocados. Skipping these high fat treats will also reduce your calorie and sugar intake. If you feel like you are already overweight, losing as little as 5-10 pounds or 2-5 kg can help lower your blood pressure and cholesterol levels. High blood pressure is the major cause of strokes so is important to control. Being overweight can also lead to other health conditions such as diabetes which is another factor that can increase the risk of a stroke.

Managing high blood pressure

High blood pressure (hypertension) is a major risk factor for stroke. A blood pressure level of 160/95 has been shown to double the risk of stroke compared to a level of 120/80. This is quite a scary statistic when you consider that one in four of us will develop high blood pressure at some stage in our lives. The good news is that high blood pressure is easily detected and can be effectively treated with lifestyle changes and medication. It is recommended that blood pressure is maintained at a level of 140/90, or lower for people with a history of stroke or TIA. Aiming to reduce salt intake, reducing alcohol consumption, avoiding exposure to high and low temperatures, and sauna or steam bath sessions, moderation in exercise schedules. High blood pressure is not a direct cause of stroke but it contributes to the hardening and thickening of arteries. This, in turn, leads to blockages in the arteries and ultimately results in a stroke. High blood pressure also puts a strain on blood vessels in the brain and causes weakening in the small vessels, increasing the likelihood and seriousness of a stroke. It is estimated that people who reduce their blood pressure by 10mmHg (systolic) have a 30% lower risk of stroke and other heart-related diseases. This can be achieved through simplistic weight loss, reduced salt intake, and healthier eating habits.

Quitting smoking and reducing alcohol consumption

There are strong correlations between smoking and increased risk of stroke, to the point where almost 20% of strokes in the UK occur as a result of smoking. This is due to the fact that the harmful chemicals in tobacco smoke damage the cardiovascular system, helping to create a build-up of fatty deposits in the arteries and damage to blood vessels. Diabetes further increases health problems in smokers in terms of a higher risk of heart disease and narrowing of the arteries. However, the good news is that the risk of stroke significantly decreases soon after the smoker becomes smoke-free, and continues to decrease the longer they continue to abstain from tobacco. Come Quit provides around the clock advice and support to those seeking to quit smoking.

Stroke risk is elevated with an increase of alcohol consumption. What’s often overlooked is the well-established clarity of the link between even moderate drinking and risk of stroke. Just one drink a day can increase the risk of stroke by 14%.

Controlling diabetes and cholesterol levels

There are different ways to control blood sugar levels including tablets, insulin, and making changes to your diet and level of physical activity. An excellent approach to develop long-term changes is to attend a diabetes self-management education course. Talk to your diabetes doctor about what approach is best for your individual circumstances.

The most effective way to reduce the risk of stroke in diabetics is by controlling your blood sugar level. There is strong evidence to show that a higher blood sugar level is linked to an increased risk of stroke and other complications such as damage to the eyes, kidneys, and heart. In fact, as a general rule, every 1% reduction in HbA1c (average blood sugar level) reduces the risk of microvascular complications (damage to small blood vessels throughout the body) by 40%. High blood sugar levels can cause damage to the blood vessels, which increases the risk of fatty deposits in the blood vessel walls. High blood sugar can also make the blood more likely to clot. Damage to the blood vessels is the main underlying cause of stroke and leads to other stroke risk factors such as high blood pressure and high cholesterol levels.

People with diabetes have a higher risk of stroke, so it is very important for them to understand the relationship between the two conditions. The majority of people that have diabetes do not have symptoms. It is a good idea to get tested for diabetes if you have any of the risk factors for diabetes. To find out whether you are at increased risk of diabetes, check whether you are overweight, have low activity level, have a poor diet, or have a family history of diabetes. If you have any of these risk factors, then you should be tested when you are over 40 years old, and if you have no risk factors, you should be tested when you are 50 years old.