An Overview of Stroke

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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.

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

Some people experience strokes in which the effects are far less impactful than those with more serious cases, and vice versa. Strokes are treatable, so it is important to be able to recognize a stroke, so that you can get the right emergency treatment

Symptoms

Recognizing the symptoms of a stroke can save a life. The symptoms of a stroke can be remembered by the acronym FAST:

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

Additional stroke symptoms include:

  • Body weakness: If you experience weakness on one side of your face, arms, hands, or legs, you should obtain medical attention right away. 
  • Facial weakness: Mouth drooping, eyelid drooping, or uneven eyelids are also characteristics of a stroke. Of course, not everyone has a perfectly symmetrical face, but a change in someone you know, or an obvious asymmetry, is usually a sign of stroke.
  • Speech changes: Slurred speech, garbled speech, or words that do not make sense are signs of a stroke. 
  • Vision changes: Blurred vision, double vision, vision loss, or partial vision loss can be the sign of a stroke or another serious eye emergency. If you suspect that someone is not seeing the same objects you are seeing, you need to treat this as a medical emergency because many strokes affect vision, including strokes of the eye itself.
  • Falling: Balance and coordination problems caused by a stroke make it difficult to walk or to use your hands.
  • Sensory abnormalities: Numbness, tingling, or a burning sensation may not be as noticeable as weakness or vision changes, but it may be the only sign of a stroke. Usually, sensory deficits occur on one side of the body during a stroke.
  • Headaches or dizziness: These may signal a stroke or another urgent neurological condition. It is best to err on the side of caution and get medical attention right away.
  • Confusion: If you are talking to someone who becomes unusually confused, it is essential to take this seriously. 

Time spent in deciding whether or not to obtain medical attention could end up as time wasted from getting the proper treatment.

Causes

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

  • Heart disease, cerebrovascular disease, and carotid artery disease
  • Hypertension and malignant hypertension
  • High cholesterol, fat, and triglyceride levels
  • Diabetes
  • Blood disorders and infections
  • Autoimmune or severe systemic disease
  • Smoking
  • Obesity
  • Sedentary lifestyle
  • Excessive stress
  • Drugs

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.

Diagnosis

If you or someone you know experiences any of the symptoms of stroke, it is important to get professional medical attention immediately. Though stroke severity can vary, it is one of the leading causes of death and disability. Prompt medical care is the best way to prevent the worst and reduce the level of disability for the majority of stroke survivors.

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

Treatment

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. Many stroke patients undergo physical or occupational therapy to regain skills they may have lost as a result of the damage caused by stroke.

Common Long-term Effects of Stroke

Not everyone who experiences a stroke will face all of these concerns or do so at the same level but a stroke can impact:

  • 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

​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.

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.

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