Strokes occur when the blood supply to the brain is interrupted, depriving one or more areas of the brain of vital oxygen supplies. Most often, the disruption to blood flow is caused by a clot that lodges in one of the carotid arteries, major arteries located on either side of the neck that supply blood to the brain or narrowing or blockage in one of these arteries. These are called ischemic strokes, and they account for about 90 percent of all strokes. Less commonly, strokes can occur when blood vessels in the brain rupture and bleed, causing what’s known as a hemorrhagic stroke. Both types of stroke can cause temporary or permanent impairment of functions like speech, cognition or movement, depending on where the stroke occurs, and some strokes are serious enough to cause death.
Like an ischemic stroke, transient ischemic attacks (TIAs, sometimes called “mini-strokes”) occur as a result of arterial blockage. However, TIAs are very brief and appear to resolve on their own - but that doesn’t mean they don’t cause damage. A single TIA is not life-threatening, but they often act as a precursor to a major stroke, and over time, multiple TIAs can cause deterioration in certain areas of the brain, causing both functional and cognitive deficits.
The American Heart Association recommends people memorize the acronym F.A.S.T.:
Facial drooping, usually on one side
Arm or other limb weakness
Time to call 9-1-1
Other symptoms include limb paralysis or numbness, especially when limited to one side, problems with vision and severe headache.
Strokes have been associated with several risk factors, including:
high blood pressure
family history of stroke or TIA
personal history of TIA
People with any of these risk factors should consider stroke screening including Doppler ultrasound of the carotid arteries to look for signs of narrowing or blockage that could increase their risk of having a stroke.