Stroke is the 5th leading cause of death in the US, with one person dying every 4 minutes as a result. For black people, stroke is the 3rd leading cause of death.
Strokes occur due to problems with the blood supply to the brain: either the blood supply is blocked or a blood vessel within the brain ruptures, causing brain tissue to die. A stroke is a medical emergency, and treatment must be sought as quickly as possible.
There are three main kinds of stroke:
- Ischemic strokes
- Hemorrhagic strokes
- Transient ischemic attacks (TIAs), also referred to as mini-strokes
Contents of this article:
You will also see introductions at the end of some sections to any recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions.
Fast facts on stroke
Here are some key points about stroke. More detail and supporting information is in the main article.
- During a stroke, the brain does not receive enough oxygen or nutrients, causing brain cells to die.
- There are three main kinds of stroke: ischemic strokes, hemorrhagic strokes and transient ischemic attacks.
- Ischemic strokes are caused by a narrowing or blocking of arteries to the brain.
- Hemorrhagic strokes are caused by blood vessels in and around the brain bursting or leaking.
- Strokes need to be diagnosed and treated as quickly as possible in order to minimize brain damage.
- Remembering the F.A.S.T. acronym can help with recognizing the onset of stroke (Face, Arms, Speed, Time - explained below).
- Treatment depends on the type of stroke.
- Ischemic strokes can be treated with 'clot-busting' drugs.
- Hemorrhagic strokes can be treated with surgery to repair or block blood vessel weaknesses.
- The most effective way to prevent strokes is through maintaining a healthy lifestyle.
What is stroke?4
Stroke occurs when the supply of blood to the brain is either interrupted or reduced. When this happens, the brain does not get enough oxygen or nutrients which causes brain cells to die.
Strokes occur due to problems with the blood supply to the brain; either the blood supply is blocked or a blood vessel within the brain ruptures.
There are three main kinds of stroke; ischemic, hemorrhagic and TIA. This article will focus on ischemic and hemorrhagic strokes, as there is a separate Knowledge Center article for TIAs, which goes into specific detail about them.
In the US, approximately 40% of stroke deaths are in males, with 60% in females. According to the American Heart Association (AHA), compared to white people, black people have nearly twice the risk of a first-ever stroke and a much higher death rate from stroke.3
In 2009, stroke was listed as the underlying cause of death in 128,842 persons in the US, resulting in an age-adjusted rate of 38.9 deaths per 100,000 population. The rate was almost twice as high among non-Hispanic blacks (73.6 per 100,000), and the rate of premature death from stroke was also higher among non-Hispanic blacks than their white counterparts (25.0 versus 10.2).17
Stroke is also more likely to affect people if they are overweight, aged 55 or older, have a personal or family history of stroke, do not exercise much, drink heavily, smoke or use illicit drugs.5
What causes stroke?
The different forms of stroke have different specific causes.
Ischemic stroke is the most common form of stroke, accounting for around 85% of strokes. This type of stroke is caused by blockages or narrowing of the arteries that provide blood to the brain, resulting in ischemia - severely reduced blood flow.
These blockages are often caused by blood clots, which can form either in the arteries connecting to the brain, or in other blood vessels before being swept through the bloodstream and into narrower arteries within the brain. Clots can be caused by fatty deposits within the arteries called plaque.
Hypertension can lead to rupturing of blood vessels and hemorrhagic stroke.
Hemorrhagic stroke are caused by arteries in the brain either leaking blood or bursting open. The leaked blood puts pressure on brain cells and damages them. Blood vessels can burst or spill blood in the middle of the brain or near the surface of the brain, sending blood into the space between the brain and the skull.
Intracerebral hemorrhage is the most common type of hemorrhagic stroke and occurs when brain tissue is flooded with blood after an artery in the brain bursts. Subarachnoid hemorrhage is the second type of hemorrhagic stroke and is less common. In this type of stroke, bleeding occurs in the subarachnoid space - the area between the brain and the thin tissues that cover it.
Transient ischemic attack (TIA)4,6
TIAs are different from the aforementioned kinds of stroke because the flow of blood to the brain is only briefly interrupted. TIAs are similar to ischemic strokes in that they are often caused by blood clots or other debris.
TIAs should be regarded as medical emergencies just like the other kinds of stroke, even if the blockage of the artery is temporary. They serve as warning signs for future strokes and indicate that there is a partially blocked artery or clot source in the heart.
According to the Centers for Disease Control and Prevention (CDC), over a third of people who experience a TIA go on to have a major stroke within a year if they have not received any treatment. Between 10-15% will have a major stroke within 3 months of a TIA.6
Recent developments on stroke causes from MNT news
Individuals with poor executive function - a set of thinking skills related to planning, problem-solving and reasoning - may be at greater risk of heart attack and stroke, according to a new study published in the journal Neurology.
Workaholics may be jeopardizing their health after a new study reveals working 55 hours or more per week may lead to 33% greater risk of stroke.
Alpha-blockers are used to treat a variety of conditions, including high blood pressure, Raynaud's disease and to improve urine flow in older men with enlarged prostates. Now, a new study suggests there is a higher risk of ischemic stroke for men who take alpha-blockers but who are not already taking other blood pressure medications.
Elderly people who sleep poorly and awaken frequently are more likely to have hardened blood vessels or oxygen-starved tissue in the brain, according to a report published in the journal Stroke.
On the next page, we look at the symptoms of stroke and how to diagnose a stroke. On the final page we discuss treatment options and how strokes can be prevented.