What Is a Stroke?

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A stroke happens when there is an interruption of blood flow to a region of the brain that causes brain damage. This can result in diminished physical function, impaired thinking skills, or both, and the level to which this occurs varies depending on what part of the brain is injured and the extent of the damage. The effects of a stroke can be quite serious, but they can also be far less impactful.

Strokes are treatable, so it is important to be able to recognize a stroke when one occurs so that you can get the right emergency treatment

Each year, approximately 800,000 Americans have a stroke. Unlike heart attacks, which are painful events, strokes are not usually painful.


Types of Stroke

There are two main types of strokes—ischemic and hemorrhagic—which are differentiated by the type of blood vessel problem that has occurred.

Ischemic strokes are caused by blockage of one of the cerebral blood vessels. These can be:

  • Thrombotic, when there is a formation of a thrombus (clot) directly inside the blood vessel
  • Embolic, when the blood clot originates in other areas of the body, such as the heart, and travels to the brain causing a blockage of one of its vessels

Hemorrhagic strokes are strokes caused by a blood vessel rupture and characterized by bleeding in the brain. Hemorrhagic strokes are sub-divided into two types:

Furthermore, strokes can be classified according to their location into cortical, subcortical, brainstem and cerebellar - each one associated with different types of symptoms and signs.

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Stroke Symptoms

Recognizing the symptoms of a stroke can save a life. You can use the acronym FAST to remember them and the important step to take if you notice them:

  • Facial drooping
  • Arm weakness
  • Speech difficulties
  • Time to call emergency services

Additional stroke symptoms include:

  • Body weakness
  • Facial weakness
  • Speech changes
  • Vision changes
  • Falling
  • Sensory abnormalities
  • Headaches or dizziness
  • Confusion

Time spent deciding whether or not to obtain medical attention could end up as time that could and should have been spent getting medical treatment.


The causes of stroke are well known and mostly preventable or controllable lifestyle factors or medical conditions. Risk factors include:

  • Heart disease
  • Carotid artery disease
  • Hypertension and malignant hypertension
  • High cholesterol, fat, and triglyceride levels
  • Diabetes
  • Blood clotting disorders and infections
  • Obstructive sleep apnea
  • Smoking
  • Obesity
  • Sedentary lifestyle
  • Excessive stress
  • Drug or alcohol abuse

Stroke prevention requires adjustment of lifestyle habits, as well as good medical care aimed at detecting and regulating the health conditions that are known to lead to stroke.

Brain injury from stroke is the result of a series of biological events that occur when there is a lack of sufficient blood supply to a region of the brain. Blood flow to the brain is vitally important because blood contains the oxygen and nutrients necessary for each and every brain cell to function normally.

Even a few minutes of interrupted blood flow is enough to cause brain damage.


Though stroke severity can vary, it is one of the leading causes of death and disability. Prompt diagnosis and medical care is the best way to prevent the worst and reduce the level of disability for the majority of stroke survivors.

Certain arteries are dedicated to providing blood to defined regions of the brain—each of which control specific functions. This mapping is quite consistent from person to person.

As such, the effects of a stroke can reveal what part of the brain was affected, as well as which blood vessel was interrupted. For example, weakness indicates a stroke in the motor area of the brain. Identifying this on your neuro exam is one of the ways that your healthcare team works to diagnose stroke.

A stroke is usually confirmed based on studies such as computed tomography (CT) or magnetic resonance imaging (MRI) of the brain Other tests such as such as bloodwork, electrocardiogram (EKG), carotid ultrasound, CT or MR angiogram of the arteries in the neck and head are often performed in order to find out what caused the stroke.


Stroke is treatable in the first few hours after stroke symptoms begin. Emergency stroke treatment requires a trained medical team that can act quickly to administer powerful medications that can reduce or reverse the obstruction of blood flow before it causes permanent brain damage.

Emergency treatment such as tissue plasminogen activator (TPA) and intra-arterial thrombolysis are becoming available in more medical centers as technology advances. Even mobile stroke units are making stroke care faster and more accessible.

Stroke assessment is based on the National Institutes of Health Stroke Scale (NIHSS), a systematic assessment tool that provides a quantitative measure of stroke-related neurologic deficit.

Once stroke damage has occurred, there is no known medical or surgical treatment that can repair the brain. That is why stroke prevention and emergency treatment are so important.

Stroke recovery is about maintaining optimal health to allow the brain to recover on its own, and then ‘watching and waiting’ as recovery and healing take place.


The after-effects of a stroke may be lifelong. Many stroke patients undergo physical or occupational therapy to regain skills they may have lost as a result of the damage caused by the event.

Long-term effects of a stroke that may be focused on in the recovery period include, but are not limited to:

  • Weakness of or loss of sensation on one side of the body or the face
  • Slurred speech
  • Balance problems
  • Difficulty with problem-solving

In addition to physical rehabilitation, many patients experience behavior changes, sadness, and a sense of isolation. Attending a regular support group or one-on-one talk therapy can you process your feelings after a stroke and help you cope.

A Word From Verywell

Recognizing stroke symptoms is the key to getting the care you or someone else needs, as time is of the essence when stroke strikes. Unfortunately, many don't know much about stroke until they or a loved one is diagnosed with one. If that's your situation, learn as much as you can prepare for what's ahead. If the impact of a stroke is profound, know that life can improve. Though it may very well be that things won't be the same as before, rehabilitation and recovery can help one face the future with greater confidence.

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Article Sources
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  2. Feigin VL, Nguyen G, Cercy K, et al. Global, Regional, and Country-Specific Lifetime Risks of Stroke, 1990 and 2016. N Engl J Med. doi: 10.1056/NEJMoa1804492

  3. Centers for Disease Control and Prevention. Stroke, Updated May 2019.

  4. Hacke W. A New DAWN for Imaging-Based Selection in the Treatment of Acute Stroke. N Engl J Med. doi:10.1056/NEJMe1713367

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