Stroke occurs when a blood vessel carrying oxygen and nutrients to the brain is impaired, causing brain cells to die. Stroke can be caused by a blood clot (thrombosis), blockage (embolism) or bleeding (hemorrhage).
Stroke is the No. 5 cause of death and a leading cause of disability in the U.S.
Common symptoms after a stroke include the inability to move parts of one side of the body, difficulty with speech or swallowing, or problems with eyesight. These symptoms can disappear quickly within 24 hours, or they can persist much longer.
Types of Stroke
Strokes can be classified into two main categories:
- 87 percent are ischemic strokes - strokes caused by blockage of an artery
- 13 percent are hemorrhagic strokes - strokes caused by bleeding
An ischemic stroke occurs when a blood vessel that supplies the brain becomes blocked and blood is unable to flow to part of the brain. The brain cells and tissues begin to die within minutes from lack of oxygen and nutrients. The underlying cause of the condition is the development of fatty deposits lining the vessel walls.
Hemorrhagic strokes occur when a blood vessel that supplies the brain ruptures and bleeds. When an artery bleeds into the brain, blood compresses the surrounding brain tissue and brain cells do not receive oxygen and nutrients. In addition, pressure builds up in surrounding tissues and irritation and swelling occur.
Transient Ischemic Attack
Transient Ischemic Attack (TIA) is often called a “mini stroke.” The only difference between and stroke and TIA is that TIAs have a temporary clot. The symptoms occur rapidly and last a relatively short time. Most TIAs last less than five minutes; the average is about a minute. Unlike a stroke, when a TIA is over, there’s usually no permanent injury to the brain.
This mini-stroke is often characterized as a “warning stroke,” and any symptom should be taken very seriously as about a third of people who experience TIA go on to have a stroke within a year.