A stroke occurs when the blood supply to part of the brain is suddenly slows or stops (ischemic) or when a blood vessel in the brain bursts, spilling blood into the spaces surrounding brain cells (hemorrhagic). Brain cells die when they don’t receive oxygen and nutrients from the blood or there is bleeding into or around the brain. The symptoms of a stroke include sudden numbness or weakness, sudden confusion or trouble speaking or understanding speech; sudden trouble seeing in one or both eyes; sudden trouble with walking, dizziness, or loss of coordination; or sudden severe headache.
The type of stroke you have affects your treatment and recovery.
The three main types of stroke are:
Most strokes (87%) are ischemic strokes (Ref 1). An ischemic stroke happens when blood flow through the artery that supplies oxygen-rich blood to the brain becomes blocked. Blood clots often cause the blockages that lead to ischemic strokes.
A hemorrhagic stroke happens when an artery in the brain leaks blood or ruptures (breaks open). The leaked blood puts excessive pressure on brain cells, which damages them.
High blood pressure and aneurysms—balloon-like bulges in an artery that can stretch and burst—are examples of conditions that can cause a hemorrhagic stroke.
Transient Ischemic Attack (TIA)
A transient ischemic attack (TIA) is sometimes called a “mini-stroke.” It is different from the other types of stroke because blood flow to the brain is blocked for a short time—usually no more than 5 minutes (Ref 2). At the onset, symptoms are from a TIA or from a major type of stroke are indistinguishable. There is no way to know which type of event it is. Blood clots often cause TIAs. More than a third of those people who have a TIA and don’t get treatment have a major stroke within 1 year. Further, 10% to 15% of people will have a major stroke within 3 months of a TIA (Ref 2). Additional information on stroke can be found from the NIDDS (https://www.ninds.nih.gov/health-information/disorders/stroke), CDC (https://www.cdc.gov/stroke/index.htm).
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American Heart Association/American Stroke Association. TIA (Transient Ischemic Attack). Accessed October 6, 2016.
National Institute of Neurological Disorders and Stroke. (2009). Stroke: challenges, progress, and promise. Bethesda, MD: National Institutes of Health.
American Heart Association (AHA), Heart Disease and Stroke Statistics – 2010 Update. http://circ.ahajournals.org/content/121/7/e46#sec-23.
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