A Stroke is a medical condition in which poor blood flow to the brain results in cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. They result in part of the brain not functioning properly. Signs and symptoms of a stroke may include an inability to move or feel on one side of the body, problems understanding or speaking, feeling like the world is spinning, or loss of vision to one side. Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than one or two hours it is known as a transient ischemic attack (TIA) or mini-stroke. A hemorrhagic stroke may also be associated with a severe headache. The symptoms of a stroke can be permanent. Long-term complications may include pneumonia or loss of bladder control.
- Stroke kills about 140,000 Americans each year—that’s 1 out of every 20 deaths
- Someone in the United States has a stroke every 40 seconds. Every 4 minutes, someone dies of stroke
- Every year, more than 795,000 people in the United States have a stroke. About 610,000 of these are first or new strokes
- About 185,00 strokes—nearly 1 of 4—are in people who have had a previous stroke
Stroke was the second most frequent cause of death worldwide in 2011, accounting for 6.2 million deaths (~11% of the total). Approximately 17 million people had a stroke in 2010 and 33 million people have previously had a stroke and were still alive. Between 1990 and 2010 the number of strokes decreased by approximately 10% in the developed world and increased by 10% in the developing world. Overall, two-thirds of strokes occurred in those over 65 years old. South Asians are at particularly high risk of stroke, accounting for 40% of global stroke deaths.
It is ranked after heart disease and before cancer. In the United States stroke is a leading cause of disability, and recently declined from the third leading to the fourth leading cause of death. Geographic disparities in stroke incidence have been observed, including the existence of a 'stroke belt' in the southeastern United States, but causes of these disparities have not been explained.
The risk of stroke increases exponentially from 30 years of age, and the cause varies by age. Advanced age is one of the most significant stroke risk factors. 95% of strokes occur in people age 45 and older, and two-thirds of strokes occur in those over the age of 65. A person's risk of dying if he or she does have a stroke also increases with age. However, stroke can occur at any age, including in childhood.
Family members may have a genetic tendency for stroke or share a lifestyle that contributes to stroke. Higher levels of Von Willebrand factor are more common amongst people who have had ischemic stroke for the first time. The results of this study found that the only significant genetic factor was the person's blood type. Having had a stroke in the past greatly increases one's risk of future strokes.
Men are 25% more likely to suffer strokes than women, yet 60% of deaths from stroke occur in women. Since women live longer, they are older on average when they have their strokes and thus more often killed. Some risk factors for stroke apply only to women. Primary among these are pregnancy, childbirth, menopause, and the treatment thereof (HRT).
Annual frequencies in Switzerland:
In Switzerland, approximately 16,000 patients suffer a stroke every year. Brain stroke is the third leading cause of death in industrialised countries, the second leading cause of dementia, the main cause of disability in adulthood and the most common life-threatening neurological disease. In addition to the stroke of fate for each individual patient, the stroke also causes immense health costs. One in four people affected remains disabled and is no longer able to lead an independent life.
- Arterial embolisms caused by blood clots
- Thrombosis of the venous vessels
- Vascular contraction due to vasoconstriction
- Vascular tears: either spontaneous or due to high blood pressure, for example
- Spontaneous bleeding in the event of disturbed blood clotting
- Subarachnoid haemorrhage, sub- or epidural haematomas
As a sign of a stroke, several symptoms can occur suddenly and, depending on the severity of the illness, at the same time:
- Impaired vision on one or both eyes (possibly one-sided dilation of the pupil), loss of vision (hemianopsia), Double vision
- Missing perception of a part of the environment or one's own body (Neglect)
- Dizziness, nausea, vomiting, gait disorder, imbalance or coordination disorder (taxia)
- Paralysis or weakness in the face, arm, leg or half of the body
- Confusion, speech or word finding, writing or comprehension disturbance
- Severe headache with no apparent cause in cases of derailed blood pressure
- Orientation disorders
Given the disease burden of strokes, prevention is an important public health concern. Primary prevention is less effective than secondary prevention (as judged by the number needed to treat to prevent one stroke per year). Recent guidelines detail the evidence for primary prevention in stroke. In those who are otherwise healthy, aspirin does not appear beneficial and thus is not recommended. In people who have had a myocardial infarction or those with a high cardiovascular risk, it provides some protection against a first stroke. In those who have previously had a stroke, treatment with medications such as aspirin, clopidogrel, and dipyridamole may be beneficial. The U.S. Preventive Services Task Force (USPSTF) recommends against screening for carotid artery stenosis in those without symptoms.
The most important modifiable risk factors for stroke are high blood pressure and atrial fibrillation although the size of the effect is small with 833 people have to be treated for 1 year to prevent one stroke. Other modifiable risk factors include high blood cholesterol levels, diabetes mellitus, cigarette smoking (active and passive),drinking lots of alcohol and drug use, lack of physical activity, obesity, processed red meat consumption and unhealthy diet. Alcohol use could predispose to ischemic stroke, and intracerebral and subarachnoid hemorrhage via multiple mechanisms (for example via hypertension, atrial fibrillation, rebound thrombocytosis and platelet aggregation and clotting disturbances). Drugs, most commonly amphetamines and cocaine, can induce stroke through damage to the blood vessels in the brain and acute hypertension.
High levels of physical activity reduce the risk of stroke by about 26%. There is a lack of high quality studies looking at promotional efforts to improve lifestyle factors. Nonetheless, given the large body of circumstantial evidence, best medical management for stroke includes advice on diet, exercise, smoking and alcohol use. Medication is the most common method of stroke prevention; carotid endarterectomy can be a useful surgical method of preventing stroke.