Saturday, 28 April 2012

Stroke: Major causes


An ischemic stroke is caused by blockage of blood flow to the brain by a blood clot. The accumulation of plaque on artery walls (atherosclerosis or "hardening of the arteries" in common parlance) is an underlying cause of many ischemic strokes.

Atherosclerosis is a process in which fatty deposits (atherosclerotic plaque) invade the inside of blood vessels, particularly the carotid arteries on either side of the neck arteries supplying the heart and legs. Atheromatous plaque may cause stroke either by blocking blood flow, either by standing out (and be an embolus) that migrates into the blood, sometimes to the brain.

A hemorrhagic stroke is caused by bleeding in the brain (intracerebral hemorrhage) or bleeding around the brain (subarachnoid hemorrhage) resulting from a ruptured blood vessel. Sometimes cerebral hemorrhages are attributable to high blood pressure uncontrolled and, in some cases, anomalies that are within the structure of blood vessels (eg. Aneurysms or vascular malformations).

Many risk factors can cause a stroke.

Of these, there are factors you can not change, including:
  •     age - the risk of stroke increases as you get older;
  •     ethnicity - a larger percentage of First Nations people of African descent, Hispanic and South Asian high blood pressure and diabetes. These disorders increase the risk of stroke;
  •     family history - the risk of stroke may increase if a parent, brother or sister had a stroke before age 65;
  •     gender - men are at greater risk of stroke than women who are not yet menopausal;
  •     history of stroke or transient ischemic attack (TIA) - it is estimated that up to 30% of people who have suffered a stroke or TIA will make another stroke within 5 years after.
Among the factors that you can support include:
  •     high blood pressure;
  •     heart disease or atrial fibrillation (irregular heart beat);
  •     smoking;
  •     diabetes;
  •     a high cholesterol;
  •     physical inactivity;
  •     a heavy drinking (more than 2 drinks daily);
  •     stress.
Other factors can cause a stroke, including:
  •     other medical conditions such as amyloid angiopathy and antiphospholipid antibody syndrome;
  •     the use of illicit drugs such as cocaine or LSD;
  •     taking drugs such as tamoxifen *, phenylpropanolamine, and thrombolytics.
Other factors such as the use of oral contraceptives, hormone replacement or pregnancy and childbirth for women with preexisting medical conditions can increase the risk of stroke in certain circumstances. Talk to your doctor about risk factors that are relevant to your case and may affect your risk of stroke.