A stroke, or "brain attack," occurs when blood circulation to the brain fails either because blood vessels in the brains burst, or the blood flow is blocked. The former type is called a hemorrhagic stroke and the latter is called an ischemic stroke. According to the National Institute of Neurological Disorders and Stroke, approximately 700,000 Americans have a stroke every year, and about 160,000 of them die from stroke-related causes.
Although the symptoms following the stroke can be quite different depending in the location of the stroke, the causes of a stroke are the same regardless of the location of the stroke. Yet, the causes behind hemorrhagic and ischemic strokes can be quite different.
High Blood Pressure
Having high blood pressure is the most serious risk factor for both hemorrhagic and ischemic strokes. A study published in the August 2006 issue of "Hypertension Research" found that approximately 70 percent of strokes are caused by high blood pressure. High blood pressure can cause a stroke by, for example, weakening artery walls or making them thick, and can also increase buildup in arteries, making them narrower, or can loosen fatty deposits that then block the flow of blood.
Heart Problems
According to the National Institute of Neurological Disorders and Stroke, several heart disorders can cause a stroke. These include heart attacks, heart failure, infections in the heart, congenital heart defects, and irregular heart rhythms. Certain heart valve problems can also increase the risk for a stroke. These include having an artificial heart valve, a repaired heart valve, or narrowing of a heart valve. All of these can result in a blood clots that may block the vessels. Atherosclerosis builds a fatty deposit in the arteries that also results is a blockage.
Head Injuries and Brain Tumors
Stroke is common after a head or neck injury that damages a blood vessel. A growing brain tumor may also cut the brain circulation to the brain. Injury usually causes a stroke quite rapidly, while a slowly growing tumor might not show any symptoms for a long time.
References
- National Institute of Neurological Disorders and Stroke: Preventing Stroke
- "Hypertension Research"; The Strongest Independent Risk Factor for Stroke in Elderly Hypertensive Patients; Kario; August 2006.
