November 2017

Suggested Citation: Garko, M.G. (2017, November). Cardiovascular health: Stroke. Health and Wellness Monthly. Retrieved (insert month, day, year), from www.letstalknutrition.com.

Cardiovascular Health: Stroke  

 

Michael Garko, Ph.D.

Nationally Syndicated Host & Producer – Let’s Talk Nutrition

 

Introduction

 

Approximately 795,000 individuals suffers from a stroke in the United States annually, 610,000 of whom first-time/new stroke victims. Every 40 seconds on average, a person in the United States experiences a stroke, with someone dying on average every 4 minutes from a stroke (see Benjamin et al., 2017). When it is considered independently from other forms of cardiovascular diseases (CVDs), stroke ranks 5th among all causes of death, following diseases associated with the heart, cancer, chronic lower respiratory disease and unintentional injuries/accidents. Within the United States, stroke accounted for approximately 1 of every 20 deaths. Globally, in 2013 (the most recent year reported) there were 6.5 million deaths attributed to strokes, making stroke the second-leading cause of death worldwide behind ischemic heart disease (see Benjamin et al., 2017).

 

This bleak statistical portrait makes stroke nearly as infamous as coronary heart disease (CHD) and cancer, the first and second leading causes of death in the United States, respectively. In fact, stroke holds the dubious distinction of being the leading cause of adult disability and third leading cause taking the lives of Americans (Benjamin et al., 2017).

 

In this November, 2017, issue of Health & Wellness Monthly, stroke will be defined and discussed in light of its different types, health consequences, risk factors, warning signs and action steps to take. There will also be a focus on the diagnosis, treatment and rehabilitation pertaining to stroke, along with recommendations for preventing stroke.

 

Definition of Stroke

 

In simple terms, stroke is a form of cardiovascular disease (CVD) that impedes the structure and function of those blood vessels (i.e., arteries) supplying life-giving nutrients and oxygen to the brain. Stroke is also known as cerebrovascular accident (CVA).

 

More dramatically it is becoming common practice to refer to stroke as “brain attack,” an expression used in similar fashion as “heart attack” in which the obstruction of blood flow to the heart causes necrosis to the cardiac muscle cells and tissue. In the case of a brain attack, there is a partial or total interruption of oxygenated and nutrient rich blood flowing to the brain resulting in death and loss of function to the cells (e.g., neurons & glial cells) and tissues of the brain. The disrupted circulation of blood to the brain is caused either by a blocked or ruptured artery. In either case, the devastating physical and emotional disabilities resulting from a severe stroke are often permanent because the death of the oxygen-starved brain cells is permanent.

 

Types of Stroke

 

There are two major types of stokes. They are ischemic stroke and hemorrhagic stroke. Ischemic and hemorrhagic strokes are each often divided into two main categories or sub-types (see Centers for Disease Control & Prevention, 2017b).

 

 

Ischemic Stroke

 

Ischemic stroke is the most common and accounts for nearly 87% of all brain attacks (Centers for Disease Control & Prevention, 2017b). The defining feature of ischemic stroke is a partial or total obstruction of blood flow to the brain caused by a blood clot or other particle lodged within an artery transporting blood to the brain. Atherosclerosis (i.e., build-up of plaque within an artery) is the underlying disease mechanism of this type of stroke.

 

Given the nature of atherosclerosis to produce clots, the obstructed blood flow is most often caused by a built-up, stationary clot called a cerebral thrombosis, which narrows the lumen of the artery. The blockage can also be caused by a clot termed a cerebral embolism, which travels in the arterial blood stream from another part of the body, usually the heart. Other debris or particles (e.g., piece of broken off plaque, air, etc.) can cause also cause the obstruction. When a cerebral thrombus is implicated in the blockage, the brain attack is called a cerebral thrombotic stroke and when it is a cerebral embolism the brain attack is referred to as a cerebral embolic stroke.

 

Cerebral thrombotic stroke. This type of ischemic stroke is the most common type of brain attack and its odds of happening increase over time as the atherosclerotic plaque builds-up in the arteries. Cerebral thrombotic strokes typically occur during the night or in the morning when blood pressure is low. Commonly they are preceded by a transient ischemic attack (TIA) or mini-stroke (Centers for Disease Control & Prevention, 2017b).

 

Cerebral embolic stroke. With this form of ischemic stroke, the cerebral embolism wanders through the arterial system until it eventually lodges in a narrowed artery leading to the brain. The majority of these clots are formed in the heart during an episode of arrhythmia (i.e., irregular heartbeat) in which the two upper/atrial chambers of the heart flutter instead of contracting strongly in regular rhythm. Generally speaking, arrhythmias are caused by two major factors: 1. A malfunction in the way the heart receives and sends electrical impulses to make the heart beat and 2. Physical/structural problems with heart stemming from such factors as coronary heart disease, a damaged or weakened heart muscle from a heart attack or aging, congenital heart defects or infection. Nevertheless, since the heart fails to contract fully, blood pools in the upper chambers, clots, enters into the circulating blood stream and eventually lodges in a narrowed artery leading to the brain causing a stroke.

 

Hemorrhagic Stroke

 

Hemorrhagic stroke accounts for 18% of all stroke cases in the United States (American Stroke Association, 2017a).  A hemorrhagic stroke can be caused by a head injury. They can also be caused by a weakened artery in the brain which ruptures and bleeds into the surrounding area where blood accumulates and compresses the brain tissue, thereby, putting pressure on the brain, creating a lack of oxygen and nutrients and damaging it.

 

Aneurysms and arteriovenous malformations (AVMs) are two types of weakened blood vessels causing hemorrhagic strokes. An aneurysm is blood-filled pouch that swells and balloons out from a weakened area of an artery. High blood pressure can exacerbate and cause an aneurysm to burst. An arteriovenous malformation (AVM) is a cluster of abnormally formed blood vessels, any one of which can rupture and bleed (see American Stroke Association, 2017c).

 

Based on the location of the rupture and bleeding in the brain, the two main sub-types of hemorrhagic brain attacks are the subarachnoid stroke and intracerebral stroke (also referred to a cerebral).

 

Subarachnoid stroke. With subarachnoid brain attacks, an artery located on the surface of the brain bursts and hemorrhages (bleeds) into the subarachnoid space between the brain and the skull. There is no bleeding into the brain itself. Aneurysms and AVMs are usually responsible for the hemorrhaging. Spontaneous SAH is an abnormality within the brain’s arteries that weaken and leads to ruptures in the blood vessels on the surface of the brain, causing bleeding between the membranes surrounding the brain. Spontaneous SAH refers to hemorrhage that occurs without trauma to the head or neck (National Stroke Association, 2018a).

 

Intracerebral stroke. In contrast, an intracerebral stroke occurs when artery with the brain bursts and the bleeding takes place within the brain and surrounding tissue. The rupture of the artery can be caused by high blood pressure, trauma, bleeding disorders, vascular malformations, certain drugs, among other factors (National Stroke Association, 2018a). The extent of the bleeding determines the severity of intracerebral strokes.

 

Summary

 

Ischemic and hemorrhagic strokes are two main types of brain attacks. Cerebral thrombotic stroke and cerebral embolic stroke are sub-types of the former, while subarachnoid stroke and intracerebral stroke are sub-types of the latter. In all four types of brain attacks, there is a disruption of oxygenated and nutrient rich blood flowing to and within the brain caused either by a blocked or ruptured artery.

 

Health Consequences of Stroke

 

All four types of strokes are a serious threat to life and can result in long term if not permanent health consequences affecting the quality of a person’s life. Specifically, depending on the severity of a stroke and area of the brain affected, there is a constellation of effects associated with a brain attack. Strokes can potentially have physical, emotional and behavioral health consequences. Among other things, a stroke can result in the following:

 

  • Paralysis (i.e., Weakness on one side or the other of the body depending on which side of the brain was affected)
  • Vision problems
  • Sensation problems (i.e., Unable to feel numbness or parts of the body)
  • Memory loss (e.g., Unable to remember familiar objects)
  • Aphasia – Impaired speech and language skills (i.e., Unable to speak, understand speech, listen, read and write)
  • Dysarthria (i.e., Speech becomes slowed, slurred or distorted)
  • Dysphagia (Difficulty chewing and swallowing)
  • One-side neglect, that is, lack of awareness on one side of the body (e.g., Leaving food on half the plate, dressing only one side of the body, not turning head toward the direction of speech and sound, bumping into objects)
  • Emotional lability (i.e., Sudden mood swings, crying for no apparent reason or laughing uncontrollably)
  • Depression
  • Impaired motor ability (National Stroke Association, 2018b).

 

 

 

 

Warning Signs of Stroke

 

Having a stroke is a medical emergency. Therefore, it is important to know the warning signs of a brain attack so that there is not any delay in getting medical attention. The classic warning signs of a stroke are:

 

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  • Sudden confusion, trouble speaking or understanding
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking, dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause (National Stroke Association, 2018b).

 

Emergency Action Steps

 

It is not enough to know the warning signs of a brain attack. It is equally important to take the correct, immediate action when a stroke occurs so as to increase the odds of survival and decrease the chances of significant damage to the brain. The American Stroke Association (2017) recommends that if a stroke occurs, the following are the most important things to remember:

 

  • Since not all of the warning signs are present in any given episode of a stroke, do not ignore any of the warning signs of a brain attack even if they should go away.
  • Take note of the time when the first symptom manifested itself.
  • In the event the stoke victim experiences one or more warning signs that last more than a minute, call 9-1-1 immediately or the emergency medical services (EMS).
  • It is important to know that there is a drug called tissue plasminogen activator (tPA) that if administered within three hours of the onset of an ischemic stroke, the chances of long term disability can be reduced.

 

Risk Factors for Stroke

Just as with coronary heart disease (CHD), there are certain factors that put people at risk for stroke. Risk factors are variables possessing the potential to increase the likelihood of developing a particular disease. The stronger the statistical link between a risk factor and stroke the stronger the inference about that particular factor putting people at risk for experiencing a brain attack.

That being said, simply because an individual exhibits a risk factor or set of risk factors for stroke, this does not make the person an automatic candidate for a brain attack. Conversely, just because someone does not manifest any risk factor or set of risk factors for a brain attack, it should not be assumed that the person will never suffer from one. It is not uncommon for people to have brain attacks without manifesting any of the recognized risk factors for stroke.

Modifiable and Non-modifiable Risk Factors for Stroke

Frequently, risk factors for stroke are categorized into modifiable and non-modifiable risk factors. Modifiable risk factors are changeable and treatable lifestyle behaviors, along with resulting biochemical-physiological acquired conditions, which increase the likelihood of developing a stroke. This definition assumes that preventing or delaying the onset of a brain attack and its devastating consequences (i.e., disability & death) can be accomplished by eliminating or lessening risk-prone behaviors and resulting deleterious, biochemical-physiological conditions, which are treatable and controllable. Modifiable risk factors include high blood pressure, transient ischemic attacks (TIAs), smoking-tobacco use, diabetes mellitus, high blood cholesterol and other lipids, atherosclerosis, carotid artery and peripheral artery disease, physical inactivity, obesity, heart rhythm disorders (e.g., atrial fibrillation) or other heart disease, certain blood disorders (e.g., red blood cell count, sickle cell anemia) and nutrition (see Benjamin et al., 2017; American Stroke Association, 2017b).

Non-modifiable risk factors for stroke are fixed and unchangeable. They include increasing age, heredity and family history of stroke, gender, race and ethnicity. Prior experience of a stroke or heart attack is also considered a non-modifiable risk factor because the past is unchangeable.

Diagnosis, Treatment & Rehabilitation

Scope and space issues prevent a full discussion of the diagnosis, treatment and rehabilitation associated with stroke. Therefore, rather than giving the reader incomplete information on these important issues, the reader is encouraged to read Heart Disease and Stroke Statistics – Update, a report from the American Heart Association (see Benjamin et al., 2017), along with other discussions from the National Stroke Association (2018c), Centers for Disease Control and Prevention (2017a) , American Stroke Association (2018b) and American Stroke Association (2013).

Conclusion

 

There is an abundance of Hscientific evidence to show that smoking, physical inactivity and poor diet/compromised nutrition play a significant role in creating the biochemical-physiological conditions contributing to the development of CHD. As it turns out, these three factors also play a major role as modifiable risk factors in increasing the likelihood of a stroke. This is not to say that genetics, environment and non-modifiable risk factors do not play a role in creating these conditions. However, it is to say that the biochemical-physiological conditions for stroke track back, as they do with CHD, in a significant way to the modifiable, risk-prone lifestyle factors, generally, smoking, physical inactivity and poor diet-compromised nutrition, specifically. These three factors can be considered the “big three” modifiable risk factors for stroke because if people can improve in these three areas, then they significantly reduce their chances of having a stroke.

 

Stroke, like heart disease, is preventable. My series on coronary heart disease focuses on the “big three” modifiable risk factors for heart disease, among other modifiable and nonmodifiable risk factors. While the series focuses specifically on coronary heart disease, the recommendations on smoking cessation, diet and nutrition and physical activity as part of a personal program to prevent heart disease can be applied to stroke (see Garko, 2017a; Garko, 2017b; Garko, 2017c).

 

References

 

American Stroke Association (2018). Warning signs. Retrieved from http://www.strokeassociation.org/STROKEORG/WarningSigns/Stroke-Warning-Signs-and-Symptoms_UCM_308528_SubHomePage.jsp.

 

American Stroke Association (2018b). Stroke diagnosis. Retrieved from https://www.strokeassociation.org/idc/groups/stroke-public/@wcm/@hcm/documents/downloadable/ucm_309722.pdf

 

American Stroke Association (2017a). Hemorrhagic Strokes (Bleeds). Retrieved from http://www.strokeassociation.org/STROKEORG/AboutStroke/TypesofStroke/HemorrhagicBleeds/Hemorrhagic-Strokes-Bleeds_UCM_310940_Article.jsp#.WpMRsq6nHX4

 

American Stroke Association (2017b). Risk factors for stroke. Retrieved from https://www.strokeassociation.org/idc/groups/stroke-public/@wcm/@hcm/documents/downloadable/ucm_309713.pdf.

 

American Stroke Association (2017c). What Is an Arteriovenous Malformation (AVM)? Retrieved from http://www.strokeassociation.org/STROKEORG/AboutStroke/TypesofStroke/HemorrhagicBleeds/What-Is-an-Arteriovenous-Malformation-AVM_UCM_310099_Article.jsp#.WpMTd66nHX4

 

American Stroke Association (2013). Post stroke rehabilitation. Retrieved from http://www.strokeassociation.org/STROKEORG/LifeAfterStroke/RegainingIndependence/PhysicalChallenges/Post-Stroke-Rehabilitation_UCM_310447_Article.jsp#.WpQ-rK6nHX4.

 

Benjamin E.J., Blaha, M.J., Chiuve SE, et al. (2017). Heart disease and stroke statistics—2017 update: a report from the American Heart Association. Circulation. 135: e229-e445. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5408160/pdf/nihms852024.pdf

 

Centers for Disease Control and Prevention (2017a). Stroke treatment. Retrieved from https://www.cdc.gov/stroke/treatments.htm.

 

Centers for Disease Control and Prevention (2017b). Types of stroke. Retrieved from ttps://www.cdc.gov/stroke/types_of_stroke.htm.

 

Garko, M.G. (2017a, July). Coronary heart disease – Part VI:  Smoking cessation as part of a personal prevention program to combat coronary heart disease. Health and Wellness Monthly. Retrieved from www.letstalknutrition.com.

 

Garko, M.G. (2017b, August). Coronary heart disease – Part VII:  Diet and nutrition as part of a personal prevention program to combat coronary heart disease. Health and Wellness Monthly. Retrieved from www.letstalknutrition.com.

 

Garko, M.G. (2017c, September). Coronary heart disease – Part VIII:  Physical activity as part of a personal prevention program to combat coronary heart disease. Health and Wellness Monthly. Retrieved from www.letstalknutrition.com.

 

National Stroke Association (2018a). Hemorrhagic stroke. Retrieved from http://www.stroke.org/understand-stroke/what-stroke/hemorrhagic-stroke

 

National Stroke Association (2018b). Post stroke conditions. Retrieved from http://www.stroke.org/we-can-help/survivors/stroke-recovery/post-stroke-conditions.

 

National Stroke Association (2018c). Rehabilitation therapy after a stroke. Retrieved from http://www.stroke.org/we-can-help/stroke-survivors/just-experienced-stroke/rehab.

 

Suggested Citation: Garko, M.G. (2017, November). Cardiovascular health: Stroke. Health and Wellness Monthly. Retrieved (insert month, day, year), from www.letstalknutrition.com.