Stroke, sometimes called "brain attack", is a common and deadly form of cerebrovascular diseases that is caused by blocked or ruptured artery that supply the brain with oxygen and nutrient rich blood. There are two types of stroke: ischemic stroke (caused by a clot that clog the blood vessel), and hemorrhagic stroke (occur when a cerebral artery burst or leak).

Ischemic stroke is the most common type of stroke that form nearly 80% of cases. It occur when blood vessels to or into the brain become narrowed or clogged with fatty deposits or blood clots. This cuts off blood flow to brain cells and may lead to state brain injury and damage that may eventually cause death.

Symptoms of ischemic stroke emerge suddenly, and can be noticed as a weakness or paralysis of one side of the body. Speaking and thinking May also be affected and the person may have severe headache and/or confusion. These symptoms last usually for more than 24 hours. If they dimensioned before that, the condition will be considered what is called a transient ischemic attack (TIA), a warning sign for subsequent stroke.

Everyone with suspected stroke should receive a brain scan within 24 hours. The person will undergo Computerized tomography (CT) scan, or Magnetic resonance imaging (MRI). These tests will help to distinguish between stroke subtypes and determine the best treatment and if there is a need for further diagnostic tests, such as carotid ultrasound and cerebral angiogram. Blood may also be tested for clotting time and factors.

Ischemic stroke is a life-threatening condition that require immediate intervention. Emergency treatment of ischemic stroke focuses on improving oxygenation of brain cells and preventing further blood clots formation. A drug called alteplase may be given within few hours of ischemic stroke symptoms aiming to dissolve the clot that block the artery and regain cerebral perfusion to the affected area. Other treatments of ischemic stroke include blood thinners, antiplatelets. Surgery may be done to treat narrowing of carotid artery if it is the cause of ischemic stroke.

As many as 80% of strokes are preventable, thus the person has the choice to protect him/herself from stroke by controlling modifiable risk factors for ischemic stroke. Managing hypertension are among the strongest preventive measures to reduce the risk of ischemic stroke. Reducing high cholesterol levels by healthy lifestyle and prescribed drugs can significantly improve blood flow throw the cerebral arteries. Quitting smoking and limiting alcohol intake are also helpful.

Ischemic stroke is a disease occurs when a blood vessel that supply the brain is obstructed, which will deprive brain cells are of oxygen required for normal functioning. Brain cells begin to die within munities from oxygen depletion and which the functions regulated by the affected area will be affected. If not treated immediately, ischemic stroke can lead to severe long-term complication and may be fatal.

• Embolic stroke. A blood clot or plaque fragment forms somewhere in the body (usually the heart) and travels to the brain to clog a cerebral or carotid artery and prevent blood flow to certain part of the brain. About 15% of embolic strokes occur in people with atrial fibrillation.
• Thrombotic stroke. A thrombotic stroke is caused by a blood clot that forms inside one of the arteries supplying blood to the brain, commonly the large arteries. This type of stroke is usually seen in people with high cholesterol levels and atherosclerosis.

Ischemic strokes are usually caused by a blood clot that blocks or plugs a blood vessel in the brain or directing to it. Another cause is stenosis, or narrowing of the artery. The underlying condition for this type of obstruction is the development of fatty deposits lining the artery walls in a condition called atherosclerosis. Certain factors play a significant role in developing ischemic stroke, as discussed below.

Ischemic Stroke can happen to anyone at any time. However, certain factors are known to increase the risk of having this condition, such as:

• High blood pressure. Hypertension is the leading cause of stroke and the most important controllable risk factor for it. More than half of all strokes are caused by uncontrolled hypertension or high blood pressure.
• High cholesterol levels. Elevated low-density lipoprotein “LDL” levels in the blood are greatly linked to atherosclerosis that may form in the cerebral arteries and lead to ischemic stroke. It also appears that low HDL “good” cholesterol is a risk factor for ischemic stroke in men.
• Excess weight. Being overweight or obese can lead to a buildup of plaque in the arteries. Eventually, an area of plaque can rupture, causing a blood clot to form. If that happened in cerebral artery, it will cause ischemic stroke.
• Diabetes. Diabetes can affect the arteries that supply the brain leading to hardening or clogging of it with plaque. Many people with diabetes also have high blood pressure, high blood cholesterol and excess weight. This increases their risk even more.
• Poor diet. Foods high in saturated fat, trans-fat and cholesterol can raise blood cholesterol levels. Diets high in sodium (salt) can contribute to increased blood pressure. Diets with excess calories can contribute to obesity.
• Physical inactivity. Being inactive can increase the risk of hypertension, high blood cholesterol, diabetes, heart disease and stroke.
• Atrial fibrillation. The heart’s upper chambers quiver instead of beating effectively, which can let the blood pool and clot. If a clot breaks off, enters the bloodstream and lodges in an artery leading to the brain, a stroke results.
• Other heart diseases. People with coronary heart disease or heart failure have a higher risk of stroke than those with hearts that work normally. Dilated cardiomyopathy (an enlarged heart), heart valve disease and some types of congenital heart defects also raise the risk of stroke.
• Transient ischemic attack (TIA). This condition has the same symptoms as a stroke, but it tends to only last between a few minutes and a few hours before disappearing completely. TIA should never be ignored as it is a serious warning sign for improper blood supply to the brain and means an increased risk of having an ischemic stroke in the near future.
• Sickle cell anemia. This genetic disease cause red blood cells to misshape. Sickled red blood cells are less able to carry oxygen to tissues and organs and also tend to stick to blood vessel walls, which can block arteries to the brain and cause an ischemic stroke.
• Carotid artery disease. The carotid arteries in the neck supply blood to the brain. A carotid artery narrowed by fatty deposits from atherosclerosis may become more prone to be blocked by a blood clot and lead to ischemic stroke.
• Peripheral artery disease. It is a narrowing of blood vessels carrying blood to leg and arm muscles. It’s caused by fatty buildups of plaque in artery walls. People with peripheral artery disease have a higher risk of carotid artery disease, which raises their risk of ischemic stroke.
• Migraine headaches. According to Johns Hopkins University, USA, suffering from Migraines increases the risk of having ischemic stroke 2.3 times. The risk is 2.5 times higher for people with migraines that usually preceded by a perceptual disturbance called “aura”, and the risk can increase up to 2.9 times among women.
• Environmental factors. A recent study at Auckland University of Technology has found air pollution causes 10%, 34% of stroke in high, and low and middle-income countries, respectively.
• Smoking Cigarette. Smoking causes about a two-fold increase in the risk of ischemic stroke. It has been linked to the buildup of fatty substances in the carotid artery and reduced amount of oxygen the blood.
• Excess alcohol intake. Excessive alcohol consumption can lead to high blood pressure and trigger irregular heartbeat called atrial fibrillation, both of which can increase the risk of having a stroke.
• Aging. Stroke risk increase with age. Studies mentioned by national health institutes, USA, show the risk of stroke doubles for each decade between the ages of 55 and 85. However strokes also can occur in childhood or adolescence.
• Gender. Men have a higher risk of stroke than women. Women are usually older when they have strokes, and they're more likely to die of strokes than are men. Taking birth control pills and being pregnant also increase the risk among women.
• Race. Blacks have an age-adjusted risk of death from stroke that is 1.49 times that of whites. Hispanics have a lower overall incidence of stroke than whites and blacks but more frequent lacunar strokes and stroke at an earlier age.

The common pathway of ischemic stroke is lack of sufficient blood flow to perfuse cerebral tissue, due to narrowed or blocked arteries leading to or within the brain. Narrowing is commonly the result of atherosclerosis. As the plaques grow in size, the blood vessel becomes narrowed. Damaged areas of an atherosclerotic plaque can cause a blood clot to form (thrombus). A Blood clot can also from elsewhere in the body and travel through the circulatory system (embolus) and reach narrower blood vessels.

A thrombus or an embolus can occlude a cerebral artery and cause ischemia in the affected vascular territory. Without adequate blood supply and thus lack of oxygen, brain cells lose their ability to produce energy. Cells in the affected area switch to anaerobic metabolism, which leads to releases a by-product called lactic acid. Lactic acid is an irritant, which has the potential to destroy cells by disruption of the normal acid-base balance in the brain.

The cell membrane also undergos changes that lead to excess calcium entry to the cells, which activates enzymes that digest cell proteins and cell membranes. As the cell's membrane is broken down, it becomes more permeable, and more ions and harmful chemicals enter the cell. Mitochondria break down, releasing toxins and factors induce programmed cell death. If the cell dies through this process, it toxic chemicals into the environment around it, which poison nearby neurons, and can overexcite them.

The signs and symptoms of a stroke vary from person to person but usually begin suddenly. As different parts of the brain control different parts of your body, the symptoms will depend on the part of the brain affected and the extent of the damage. The major manifestations of stroke include:

• Sudden numbness, weakness, or even paralysis of face, arm and leg, especially on one side of the body;
• Sudden confusion or trouble speaking or understanding speech;
• Sudden trouble seeing in one or both eyes;
• Sudden trouble with walking, dizziness, or loss of balance or coordination;
• Sudden severe headache with no known cause. It may be accompanied by vomiting, or altered consciousness.

Having stroke symptoms may indicates that the person is affected by a stroke, or at least a transient ischemic attack. A number of tests can then be carried out to help confirm the diagnosis and determine the cause and severity of the condition. They include:

• Computerized tomography (CT) scan. A CT scan uses a series of X-rays to create a detailed image of the brain. A CT scan can show a hemorrhage, tumor, stroke and other conditions. Doctors may inject a dye into the bloodstream to view blood vessels in the neck and brain in greater detail. This procedure is called computerized tomography angiography.
• Magnetic resonance imaging (MRI). An MRI scan uses a strong magnetic field and radio waves to produce a detailed picture inside the body. This will provide greater detail of brain tissue, allowing smaller, unknown or more unusually located areas affected by a stroke to be identified. A dye may also be used to create more detailed picture.
• Blood tests. If the person is being evaluated for stroke, it is likely that the doctor will order some blood tests. Stroke cannot be diagnosed by a blood test alone. However, these tests can provide information about stroke risk factors and other medical problems which may be important. Coagulation tests, such as PT, PTT, and INR are commonly used. Others include Complete blood count (CBC), Blood chemistry tests, and lipid profile.
• Swallow tests. A swallow test is essential for anybody who has had a stroke, as swallowing ability is commonly affected early after a stroke, and so food and drink may get into the trachea and then into the lungs (called aspiration), which can lead to pneumonia. In the test, the patient has to be able to swallow a few teaspoons of water without choking and coughing.
• Carotid ultrasound. A carotid ultrasound scan can help show if there is any narrowing or blockages in the neck arteries leading to the brain. An ultrasound scan involves using a small probe to send high-frequency sound waves into the body. When these sound waves bounce back, they can be used to create an image of the inside.
• Cerebral angiogram. In this test, the doctor inserts a thin, flexible tube (catheter) through a small incision, usually in the groin, and guides it through the major arteries and into carotid or vertebral artery. Then the doctor injects a dye into the blood vessels to make them visible under X-ray imaging. This procedure gives a detailed view of arteries in the brain and neck.
• Echocardiogram. An echocardiogram uses sound waves triggered by a probe that is moved across the chest to create detailed images of the heart. It can find a source of clots in the heart that may have traveled to the brain and caused stroke. It is also helpful to evaluate heart function and abnormalities, which is also related to stroke.

Stroke is a medical emergency that need to be treated immediately. Early treatment may minimize the long-term effects of a stroke and prevent death. Different treatments are required for the different types of stroke, so a rapid diagnosis will make treatment more straightforward. Treatment for ischemic stroke include:

• Tissue plasminogen activator (tPA, also known as alteplase). tPA is the Gold Standard of treating ischemic stroke, as it works by dissolving the clot and improving blood flow to the part of the brain being deprived of it. This drug is most effective if started as soon as possible after the stroke occurs and is not generally recommended if more than four-and-a-half hours have passed. However, before alteplase can be used, it is very important to confirm a diagnosis of an ischemic stroke, because the medication can worsen the bleeding that occurs in hemorrhagic strokes.
• Antiplatelet. Most people will also be offered a regular dose of aspirin which - as well as being a painkiller - makes platelets less sticky, reducing the chances of another clot forming. In addition to aspirin, antiplatelet medications can include clopidogrel and dipyridamole.
• Anticoagulants. These drugs can help reduce the risk of developing further blood clots in the future, especially for people who have a history of blood clotting and atrial fibrillation. Warfarin, rivaroxaban, dabigatran and apixaban are examples of anticoagulants for long term use. Heparins are only given by injection to be used in the short time.
• Carotid endarterectomy. Some ischemic strokes are caused by narrowing of the artery in the neck that carries blood to the brain (carotid artery). In this procedure, the surgeon makes an incision along the front of the neck, opens the carotid artery and removes fatty deposits (plaques) that block it.
• Carotid Angioplasty. In an angioplasty, a surgeon gains access to the carotid arteries most often through an artery in the groin, where can gently and safely navigate to the carotid arteries in the neck. A balloon is then used to expand the narrowed blood vessel. Then a stent can be inserted to support the opened artery.
• Rehabilitation. After emergency treatment and surgery, stroke care focuses on helping the person regain his strength and recover as much function as possible and return to independent living. The health care providers will try to help the patient to deal with lost functions affected by stroke, or even regain them after long term rehabilitation program. The program may start in the hospital, then to be continued in a rehabilitation unit of the same hospital, another rehabilitation unit or skilled nursing facility, an outpatient unit, or in the patient home. It may involve physical therapy, Speech therapy, diet plan, and/or other therapies required.

A stroke can sometimes cause temporary or permanent disabilities, depending on how long the brain lacks blood flow and which part was affected. Complications may include:

• Paralysis or loss of muscle movement. The patient may become paralyzed on one side of the body, or lose control of certain muscles, such as those on one side of the face or one arm. Usual daily activities, such as walking, eating and dressing may become very hard, or even impossible.
• Difficulty contacting or swallowing. A stroke may cause to have less control over the way the muscles in the mouth and throat move, making it difficult to talk clearly (dysarthria), swallow or eat (dysphagia). The person also may have difficulty with language (aphasia), including speaking or understanding speech, reading or writing.
• Memory loss or thinking difficulties. Many people who have had strokes experience some memory loss. Others may have difficulty thinking, making judgments, reasoning and understanding concepts.
• Emotional and behavioral problems. People who have had strokes may have more difficulty controlling their emotions, or they may develop depression, especially with huge disability caused by stroke. They may also become more withdrawn and less social or more impulsive.
• Pain. People who have had strokes may have pain, numbness or other strange sensations in parts of their bodies affected by stroke.
• Sensitive to temperature changes, especially extreme cold after a stroke. This complication is known as central stroke pain or central pain syndrome. It generally develops several weeks after a stroke, and it may improve over time.

The good news is that 80 percent of all strokes are preventable. Prevention of a first or recurrent stroke is based on treating an individual's underlying risk factors for stroke. Prevention focuses on:

• Healthy Diet. A lot of foods are good for the brain and the body. Monounsaturated and polyunsaturated fats actually help lower blood cholesterol levels. Examples of these foods are avocado, nuts, seeds, tofu and some oils like olive and sesame oils. Eating Fish high in omega-3 fatty acids, such as salmon and tuna is recommended about twice a week. High fiber foods play another major role in controlling and reducing the risk of ischemic stroke, as they can decrease serum total and low-density lipoprotein (LDL) levels. Fiber-rich Foods include fruits, legumes, vegetables and whole grains. Healthy eating includes also avoiding some foods that considered bad for heath. People who have risks of stroke are advised to limit their intake of red meat, Palm and coconut oils, sugary foods and beverages, salt, alcohol and trans-fat. The last one is found in products made with hydrogenated oils and fats that could be found at stick margarine, baked goods and coffee creamers.
• Physical Activity. Regular exercising can lower many ischemic stroke risk factors, including LDL cholesterol, high blood pressure, and excess weight. Physical activity also can lower the risk for diabetes and raise HDL cholesterol level. It is preferred for the person to ask the doctor how much and what kinds of physical activity are safe and effective for him/her. The general target is 150 minutes moderate-intensity aerobic physical activity per week or 75 minutes a week of vigorous-intensity aerobic physical activity or a combination of the two with muscle-strengthening for at least 2 days per week.
• Maintaining a Healthy Weight. Having normal body weight is important for overall health and can lower the risk for ischemic stroke. This can be achieved by following a healthy eating plan and keeping physically active. A general goal to aim for is a BMI of less than 25 and a waist circumference that is less than 35 inches (88.9 cm) for women or less than 40 inches (101.6 cm) for men. If the person is overweight or obese, a loss of just 3-5% of current weight can lower triglycerides, blood glucose, and the risk of developing type 2 diabetes. Greater amounts of weight loss can improve blood pressure readings, lower LDL cholesterol, and increase HDL cholesterol, thus stroke risk will decrease.
• Give up smoking. Smoking is a major risk factor for developing atherosclerosis that can lead to ischemic stroke. If the person has a trouble quitting smoking on his own, he has to talk with his doctor about programs and products that can help quitting. Support group in hospitals, workplaces, or community groups offer classes to help people quit smoking.
• Stress Management. Learning how to manage stress, relax, and cope with problems can improve emotional and physical health. Meditation, Physical activity and deep breathing are of these helpful techniques that also boosts cerebrovascular health, in contrast to bad ways to cope with stress - such as drinking, smoking, or overeating – that worsen the problem inside the arteries.
• Controlling chronic illnesses. If the person has hypertension, he should aim to manage this condition with healthy life style (primarily limiting sodium intake) and taking prescribed medications. Maintaining blood glucose levels within targeted levels in case of diabetes will help prevent developing of stroke. Atrial fibrillation is another risk factor for stroke that should be controlled either by medications or devices that adjust cardiac electrical activity. Having high cholesterol levels should force to adjust these levels by healthy life style and cholesterol lowering drugs prescribed.
• Treating a transient ischemic attacks (TIA). TIA is considered a warning sign for a probable full stroke occurring in the future, with the highest risk in the days and weeks following the attack. In addition to healthy life style, affected people may be given drugs that reduce the chance of blood clotting, such as antiplatelets, anticoagulants, and statins. If diagnostic tests show atherosclerosis in the carotid artery, then it could be treated with Carotid endarterectomy to reduce the risk of recurrent TIAs and strokes.

How a person is affected by ischemic stroke depends on the location and amount of brain damage caused by the stroke, the ability of other healthy areas of the brain to take over functioning for the damaged areas, and rehabilitation. In general, the less damage there is to the brain tissue, the less disability results and the greater the chances of a successful recovery. The person has the greatest chance of regaining the lost abilities during the first few months after a stroke. People who have larger strokes may be permanently paralyzed on one side of their body or lose their ability to speak. More than 2/3 of survivors will have some type of disability, and about half of them will have some long-term problems with talking, understanding, and decision-making.

According to mayo clinic, Researchers have found that the central nervous system is adaptive and can recover some functions of dead cells. They also have found that it's necessary to keep practicing regained skills. Although some stroke survivors recover quickly, most need some form of stroke rehabilitation long term, possibly months or years after their stroke. The duration of stroke rehabilitation depends on the severity of the stroke and related complications.

People who have an ischemic stroke have a better chance of surviving than those affected by hemorrhagic stroke. However, cardiogenic emboli - where blood clot originates in the heart and move to brain artery - are associated with the highest 1-month mortality in patients with acute stroke. The risk for a second stroke is highest during the weeks or months after the first stroke. The risk begins to decrease after this period.

As per world heart federation, 15 million people worldwide suffer a stroke every year. Nearly five million die and another five million are left permanently disabled. By this, Stroke is considered the second leading cause of disability, after dementia. Disability may include loss of vision and/or speech, paralysis and confusion. Stroke is the second leading cause of death worldwide and affects mainly old adults. It is less common in people under 40 years, although it does happen. In young people the most common causes are high blood pressure or sickle cell disease that mainly affects African and Hispanic children.

The incidence of stroke is declining in many developed countries, largely as a result of better control of high blood pressure, and reduced levels of smoking. However, the absolute number of strokes continues to increase because of the ageing population. In the developing world, the incidence of stroke is increasing. The predictions for the next two decades suggest a tripling in stroke mortality in Latin America, the Middle East, and sub-Saharan Africa.

Stroke subtypes vary greatly in different parts of the world and between different races. However, World heart federation estimates that nearly 80% of all strokes are ischemic. Transient ischemic attack (TIA) is considered an alarm for reduced cerebral blood supply that need to be treated as soon as possible. According to American heart association, about a third of people who experience TIA go on to have a stroke within a year.