An Overview of Stroke

A stroke is a fairly common condition, affecting approximately 800,000 Americans and 15 million people worldwide every year. Though familiar to most people by name, most adults who have not been personally touched by a stroke do not actually know what one really is—something due, in large part, to the fact that stroke is a somewhat complicated medical issue.

If you have been told that you or a loved one have had a stroke, or that there is heightened risk for one, this may be the first time you have ever had to think about the intricacies of this condition and its effects.

Though you may be reading this at a tough time, learning more about stroke can help you get a better handle on your situation. If this is not you, getting up to speed on this information now may one day save your life or the life of someone you know.

What Is a Stroke?

Blood clots can travel through the bloodstream and block oxygen to the brain.

A stroke happens when there is an interruption of blood flow to a region of the brain causing brain damage.

This can cause 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. 

It's important to keep that last part in mind: Some people can experience strokes in which the effects are far less impactful than those with more serious cases, and vice versa.

Types of Stroke

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

Furthermore, there are three major categories of stroke, which are differentiated based on which region of the brain is affected.

Cortical Stroke (Large Vessel Stroke): A stroke that affects the cerebral cortex is defined as a cortical stroke or a large vessel stroke. A cortical stroke causes deficits in reasoning, thinking, language, memory, movement, sensation, or vision. 

Subcortical Stroke (Small Vessel Stroke): A stroke in the subcortical region of the brain is called a small vessel stroke. This type of stroke may cause memory deficits, weakness, tingling, or sensory loss.

Brainstem Stroke: brainstem stroke may cause double vision, dizziness, swallowing problems, breathing problems, or hiccups, as well as tingling or numbness.

What Causes a Stroke?

The majority of people who have a stroke are predisposed. However, most of the causes are preventable or controllable and include:

  • Heart disease
  • Cerebrovascular disease
  • Carotid artery disease
  • Hypertension
  • Malignant hypertension
  • Diabetes
  • Smoking
  • High cholesterol, fat, and triglyceride levels
  • Obesity
  • Sedentary lifestyle
  • Excessive stress
  • Drugs
  • Blood disorders
  • Infections
  • Autoimmune disease
  • Severe systemic disease

Common Long-term Effects of Stroke

Again, not everyone who experiences a stroke will face all of these concerns or do so at the same level. But this list of common long-term effects can at least give you an idea of how impactful a stroke can be:

  • Weakness of one side of the body
  • Weakness of one side of the face; a droopy eyelid
  • Vision loss or partial vision loss
  • Double vision or blurred vision
  • Slurred speech
  • Trouble understanding words or trouble with language
  • Balance and coordination problems
  • Loss of sensation of one side of the body or face
  • Lack of awareness of your surroundings or of your own body
  • Difficulty with problem solving
  • Dizziness, headaches, and pain
  • Urinary incontinence

Why Does a Stroke Affect Physical and Mental Abilities?

​Areas of the brain control specific functions of the mind and body. Because of the way the blood vessels are arranged, certain arteries are dedicated to providing blood to defined regions of the brain. If a particular artery is blocked or bleeding, the region of the brain that receives blood from that artery is affected. As a result, the functions controlled by that region of the brain become limited. A stroke in the motor area of the brain causes weakness, while a stroke in the visual area of the brain causes loss of vision.

The map of arteries and their corresponding brain regions is quite consistent from person to person. The brain regions and the functions they control are similarly well-defined among all of us, with very little variation from one individual to another. Because of this understanding, the effects of a stroke can reveal what part of the brain was affected as well as which blood vessel was interrupted.

Identifying the type of stroke is one of the ways that your healthcare team can effectively care for you if you ever experience a stroke.

How Can a Stroke Cause Brain Damage?

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. 

5 Important Things to Know About Stroke

A Stroke is Preventable
The causes of stroke are well known. Most stroke causes are related to daily habits that can be controlled (such as smoking) or medical conditions that can be treated (such as high blood pressure, diabetes, and obesity.) 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.

A Stroke Is a Medical Emergency
If you or someone you know experiences any of the symptoms of stroke, it is important to get professional medical attention immediately. Though stroke can vary, it is also one of the leading causes of death and disability. However, prompt medical care is the best way to prevent the worst and reduce the level of disability for the majority of stroke survivors.

A Stroke Is Treatable
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 Damage Cannot Be Reversed
Once stroke damage has occurred, there, unfortunately, is no known medical or surgical treatment that can repair the brain. That is why stroke prevention and emergency treatment are so important. However, scientists are discovering that the brain can heal itself through a process called neuroplasticity. Though promising, there is no method of directing neuroplasticity to encourage the brain to heal itself. 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.

You Can Save Someone’s Life if You Learn How to Recognize a Stroke
If you can take a few minutes to learn how to recognize the symptoms of a stroke, you can save your own life or the life of someone else if you are ever faced with a situation in which a stroke suddenly happens right in front of you. Be on the lookout for:

  • Sudden weakness
  • Sudden vision changes
  • Confusion
  • Falling
  • A severe headache
  • Loss of sensation of part of the body
  • Sudden speech or communication problems

A Word From Verywell

A stroke is not an easy concept to wrap your head around. The source of a stroke is deep in the arteries of the brain, the damage is buried out of sight (though you can see many of the related consequences), and the symptoms and effects vary so widely. Understanding stroke is even harder when you're trying to do it as you learn of a diagnosis. But understanding more about stroke can help you get a better grip on what you or a loved one may now face, or what you can do to reduce your chances of having a stroke in the first place. 

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 you or your loved one face the future with greater ease and confidence.

And remember: Recognizing stroke symptoms is the key to getting the care you or someone else needs, as time is of the essence when stroke strikes. Knowledge now can turn into power later.

Source:

Emprechtinger R, Piso B, Ringleb PA, Thrombectomy for ischemic stroke: meta-analyses of recurrent strokes, vasospasms, and subarachnoid hemorrhages,  Journal of Neurology, June 2016.

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