What is a stroke?


In this video, Kenneth Greenberg, MD, Medical Director Emergency Services at University Hospital & Medical Center, discusses the causes, symptoms, and treatment of a stroke.

A stroke is a life-threatening medical emergency that can be triggered by two different events: ischemia, referring to an ischemic stroke which happens when a blood vessel in the brain gets blocked, or bleeding (hemorrhagic stroke), which occurs when a blood vessel in the brain bursts. An aneurysm that ruptures can cause a hemorrhagic stroke, releasing blood into the spaces around the brain. It can be fatal if not treated immediately. Both conditions, ischemia and hemorrhagic stroke, can be the result of diseased blood vessel walls.

Stroke is when brain function is compromised from not getting the oxygen it needs, says Michael Seiff, MD, a neurosurgeon at Sunrise Hospital. In this video, he explains how blood clots or hemorrhages can cause stroke.

A stroke happens when a blood vessel carrying oxygen and nutrients to the brain is either blocked by a clot (ischemic stroke) or ruptures (hemorrhagic stroke). When this occurs, part of the brain no longer receives the oxygen it needs, and the tissue in that area starts to die.

You can have a stroke at any age. More than 25% of stroke victims are under 65. However, for every decade after age 55, your risk for stroke increases by 10%.

Transient ischemic attacks (TIAs) consist of stroke-like symptoms, which go away shortly after starting and produce no lasting damage. Even if your symptoms disappear entirely, it is critical that you follow up with a healthcare professional to address your risk for future stroke.

If you have the sudden onset of the worst headache of your life or the sudden onset of neurological symptoms, call 911 and get to a hospital immediately.

A stroke must be accurately diagnosed by the hospital's emergency department to determine the appropriate treatment. Some stroke treatments have to be given within just several hours of the stroke's onset for best success. Time is of the essence.

Dr. Daniel M. Hardy, MD

A stroke is simply defined as a blood clot in the brain that prevents the brain from getting the vital oxygen and nutrients it needs to survive. If symptoms aren’t identified in time, the brain rapidly loses function and can die. The longer it takes to identify a stroke, the worse the damage becomes.

Dr. Nicholas D Suite

Stroke is the sudden or gradual loss of blood flow to an area of the brain, causing damage to the brain that can almost always be seen on brain imaging such as a CAT scan or MRI. Stroke is caused by a blockage of blood flow into or out of the brain. It can also be due to a sudden rupture (breakage) of a blood vessel in the brain.

Prevention of stroke is possible by controlling high blood pressure, carefully managing diabetes, avoidance of smoking, lowering of cholesterol, being aware of any family history of stroke, and avoiding any activities that might put one at risk for stroke, e.g. drugs.

A stroke is when blood going to the brain stops suddenly. The brain doesn't get enough blood and can be badly damaged.

Strokes are fairly common. They are always serious. They can cause long-lasting problems with thinking, speaking, and moving. You can even die from a stroke.

A stroke, sometimes called a brain attack, occurs when a blockage stops the flow of blood to the brain or when a blood vessel in or around the brain bursts. Although many people think of stroke as a condition that affects only older adults, strokes can and do occur in people of all ages. In fact, nearly a quarter of all strokes occur in people younger than age 65.

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A stroke occurs when the blood supply to an artery in the brain becomes blocked or bursts, causing brain cells in that area to die. The problems experienced after a stroke may include the inability to move one side of the body, numbness on one side of the body, or speech or visual problems.

A stroke is when there has been damage to the brain by either a bleed (hemorrhage) or a lack of blood supply or a clot (ischemia). Some of the symptoms of a stroke include numbness or weakness on one side of the face, arms or legs. Other symptoms include dizziness, headache, visual change and slurred speech. This is an emergency and can be treated if seen within a few hours of symptoms starting. If you suspect a stroke, call 911 and seek immediate medical attention.

Stroke is often called a "brain attack." Just as a disrupted blood flow may damage or kill heart cells, so does it damage or kill brain cells. The severity of the damage depends on factors such as the location of the stroke, the extent of tissue injury, and how quickly symptoms are treated.

In ischemic strokes, which make up more than 80% of all cases, the cause is a blood clot blocking an artery supplying the brain. The clot may form in a blood vessel within the brain (thrombotic stroke), or it may form elsewhere and travel to the brain, where it lodges in a narrow vessel (embolic stroke). If the blood supply is interrupted only temporarily, so that symptoms go away in less than a day, it's called a transient ischemic attack (TIA), or a warning stroke. A TIA must be taken seriously and treated as an emergency, because at the start, there's no way to distinguish it from a full-blown stroke. In addition, about one-third of those who experience a TIA will go on to have a full stroke, often within a year.

Slightly less than 20% of strokes are hemorrhagic strokes, in which a blood vessel in the brain bursts. Not only are brain cells deprived of the blood supplied by the vessel, but surrounding tissue is also damaged, as leaking blood irritates neurons and creates pressure on the brain.

Dr. Kathleen Handal, MD
Emergency Medicine Specialist

A stroke occurs when a blood vessel to the brain or within the brain bursts or becomes blocked and no blood can flow to brain tissue. When blood flow stops, brain tissue begins to die. Time lost is brain lost! Clot-busting drugs, if given within 3 hours can open some blocked arteries. Remember 3 hours includes the time for medical evaluation. Every minute counts so immediate medical attention is important.

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Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)

A stroke is an attack on the brain, a cerebrovascular accident (CVA) caused by one of two things; too little blood reaching the brain (ischemic stroke), or too much blood pooling in the brain (hemorrhagic stroke). The distinction is important because while the mechanism that causes these two events is different, the symptoms and outcome may be the same. Either way, the timing of treatment is critical to the degree of damage and survival.

When an artery in the brain either bursts or has a blockage, it causes a stroke. There are two types of strokes. Hemorrhagic strokes result from bleeding inside the brain, which may occur if a blood vessel or aneurysm (a swelling in an artery) ruptures. Ischemic strokes, which are the most common type of strokes, result when a blood clot causes a reduction in blood flow in the brain. Strokes are a medical emergency and require quick treatment.

The brain relies on a system of arteries to keep it constantly supplied with oxygen‐rich blood. If one of these arteries is damaged or blocked, the result is a stroke. When a part of the brain is deprived of its oxygen supply for more than three or four minutes, that portion of the brain begins to die.

A stroke can happen in one of two ways: An artery may rupture and bleed into the brain tissue; or an artery may become blocked by an embolus?that is, a blood clot that travels up to the brain through the artery. The risk factors for stroke include high blood pressure, smoking, and high levels of LDL ("bad") cholesterol.

Individuals with diabetes who have a stroke are in a unique and dangerous position. In a person without diabetes, when oxygen supply to the brain is blocked, other arteries often bypass the blockage and manage to make up for the reduction in blood flow. But in diabetics, those bypass arteries are often affected by atherosclerosis (hardening of the arteries), impairing blood flow to the brain.

Damage to the brain during stroke can result in loss of the ability to move parts of the body, such as an arm or leg, as well as impairment in speech and the ability to understand. By having your cholesterol checked regularly, working to control your bad cholesterol, quitting smoking, limiting alcohol consumption, and getting your blood pressure under control, you can reduce your risk of stroke.

A stroke can be described as the sudden onset of neurologic symptoms due to a disruption of blood flow in the brain. There are two main types of strokes: ischemic and hemorrhagic. Ischemic strokes are caused by blockage of blood flow in a vessel. Hemorrhagic strokes are caused by bleeding into the brain tissue by a ruptured or otherwise damaged blood vessel.

There are two type of strokes—hemorrhage or bleeding strokes and ischemic strokes. A bleeding stroke is a rupture or a leakage of the blood vessels that leads to blood accumulation in the brain, and most of the time, needs medical intervention. With an ischemic stroke, a blood clot travels into the artery, causing a blockage. When you block the artery that supplies blood to the brain tissue that moves the arm and the leg, you won’t be able to move the arm and the leg.

Dr. Reza E. Jahan, MD

A stroke is sudden injury to the brain caused by an interruption in blood flow. This injury can be temporary or permanent and in many cases can be fatal. The sooner a person can get medical treatment, the better the chances of survival and recovery.

During a stroke, brain cells begin to die when blood flow is cut off. This causes symptoms such as sudden paralysis, problems with vision or speech, and problems walking or moving.

Dr. Charles E. Stout, MD
Diagnostic Radiologist

Charles Stout, MD, from Riverside Community Hospital gives a run-down of what a stroke really is in this video.

Jill Tyroller
Nursing Specialist

A stroke is an interruption in the blood supply to the brain, says Jill Tyroller, Stroke Program Coordinator, from Reston Hospital Center. Learn more in this video.

A stroke is any interruption of the blood flow to the brain, according to Jonathan Cross, MD, Neurologist at Aventura Hospital & Medical Center. Learn more about strokes in this video.

Continue Learning about Stroke

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.