Cerebral Vascular Accident

Cerebral Vascular Accident

Epidemiology

Cerebrovascular accident (CVA) is the clinical definition of a stroke or “brain attack.” Cerebrovascular accident is the principal cause of death in the United States and the second leading cause of death worldwide (Gibbons, 2017).  A cerebrovascular accident can produce permanent brain-damage, disability, or death, and is a perilous medical disorder that warrants emergency treatment (Gibbons, 2017).

The definition of a cerebrovascular accident is the abrupt death of brain cells due to inadequate blood perfusion to the brain, which may be caused by an obstruction (ischemic stroke) or a ruptured vessel (hemorrhagic stroke) (Ellis, 2016). Brain cells, when deprived of oxygen, deteriorate within minutes, and symptoms begin to manifest in the areas of the body being controlled by that particular region of the brain (Ellis, 2016). Lack of blood supply to the brain can lead to temporary or permanent loss of mobility, memory, dialog, or feeling (Ellis, 2016). There are two major types of cerebrovascular accidents which are briefly discussed below. A cerebrovascular accident can either be ischemic or hemorrhagic (Ellis, 2016). An ischemic stroke is the disruption of blood supply to the brain caused by a clot, whereas a hemorrhagic stroke is bleeding in the brain posed by the bursting of a blood vessel (Ellis, 2016).

There are a variety of risk factors associated with a cerebrovascular accident; these can be either modifiable (can be changed or treated), or nonmodifiable (cannot be modified or treated). Among the modifiable risk factors are high blood pressure, obesity, smoking, diabetes, endocarditis, and periodontal disease (CDC, 2017). Additionally, the use of illegal drugs (i.e., cocaine and amphetamines), alcohol consumption or abuse, specific medications, the absence of physical activity, stress, and even depression may also be contributing risk factors for a stroke (CDC, 2017). Unlike the modifiable risk factors, the nonmodifiable risk factors are not controllable or treatable and include age, race, and gender (CDC, 2017). According to the Center for disease control and prevention “Risk of having a first stroke is nearly twice as high for blacks as for whites, and blacks have the highest rate of death due to stroke,” (CDC, 2017). While death tolls have decreased for years amongst all ethnicities, the Hispanic ethnicity has witnessed a surge in mortality rates since 2013 (CDC, 2017).

The United States has an approximate thirty-four-billion-dollar yearly expense associated with healthcare services provided to patients that have suffered a cerebrovascular accident (Benjamin, Blaha, & Chiuve, 2017). Cerebrovascular accidents are also the foremost cause of long-standing acute disability in stroke survivors sixty-five years of age and older due to total or partial loss of body motor function (Benjamin, Blaha, & Chiuve, 2017). In 2015, out of every 100,000 males residing in the United States, 37.8 died as a result of a cerebrovascular accident (Benjamin, Blaha, & Chiuve, 2017). While, 36.9 out of every 100,000 female residents in the United States similarly died from a cerebrovascular accident (Benjamin, Blaha, & Chiuve, 2017).

Cerebrovascular accident, otherwise known as stroke, represent one out of every twenty deaths in the United States and is ranked fifth amongst all causes of death (Benjamin, Blaha, & Chiuve, 2017). Cerebrovascular accident kills approximately one-hundred and thirty-three thousand individuals every year, roughly one person every four minutes in the United States (Benjamin, Blaha, & Chiuve, 2017). Cerebrovascular accident was the second-leading comprehensive source of mortality in 2013 accounting for eleven out of each hundred overall deaths worldwide (Benjamin, Blaha, & Chiuve, 2017). Every year, an estimated seven-hundred and ninety-five thousand people encounter an initial or recurring stroke (Benjamin, Blaha, & Chiuve, 2017). Roughly six-hundred and ten thousand are initial attacks, while one-hundred and eighty-five thousand are recurring attacks (Benjamin, Blaha, & Chiuve, 2017). Every forty seconds in the United States a person suffers from a cerebrovascular accident (Benjamin, Blaha, & Chiuve, 2017).

Pathophysiology

Blood flow to the brain, scalp, and face is delivered via the left and right common carotid arteries. The common carotid arteries have two segmentations; the external carotid arteries, which supply the scalp and face with blood and the internal carotid arteries, which provide blood to the ventral segment of the cerebrum (Genentech, 1999). In conjunction with the vertebrobasilar arteries, the carotid arteries help structure the Circle of Willis; located at the base of the brain (Genentech, 1999). Additional arteries (anterior cerebral, middle cerebral, posterior cerebral) ascend and travel to all areas of the brain from the Circle of Willis (Genentech, 1999).

The anterior cerebral artery provides the frontal lobes, the areas of the brain that govern logical reasoning, character, and voluntary movement (particularly of the legs) with blood (Genentech, 1999). A cerebrovascular accident in the anterior cerebral artery generates weakness of the opposing leg (Genentech, 1999). The middle cerebral artery supplies blood to a part of the frontal, temporal (lateral surface), and parietal lobes, as well as the primary motor and sensory sections of the face, throat, arm, hand, and speech areas in the dominant hemisphere (Genentech, 1999). This artery is also considered to be the most frequently obstructed artery in a cerebrovascular accident (Genentech, 1999). Lastly, the posterior cerebral arteries are responsible for the blood supply delivered to the occipital and temporal lobes of both hemispheres (Genentech, 1999). Symptoms accompanying an obstruction of this artery are dependent upon the location of the blockage (Genentech, 1999).

The chief pathophysiology of a cerebrovascular accident becomes concealed by cardiac or blood vessel disease (Ellis, 2016). Cerebrovascular accidents cause injury or death to brain cells by an interrupting blood supply to an area causing disabilities, such as paralysis or speech impairments (Ellis, 2016). The disturbance of blood flow to the brain instigates an intricate sequence of cellular metabolic events (Ellis, 2016). This cascade of events commences with diminished cerebral blood flow causing an unstable preservation of aerobic respiration, which in turn forces the mitochondria to shift to anaerobic respiration (Ellis, 2016). Thus, producing massive amounts of lactic acid fostering an alteration in pH, which renders the neurons powerless of creating adequate amounts of ATP, in turn, causing a loss of function (Ellis, 2016).

Clinical presentation of a cerebrovascular accident is unique to the size and site of the area with inadequate perfusion, and the amount of collateral blood flow (Stroke Association, 2014). Anyone can experience a cerebrovascular accident. However, there are specific factors that make certain people more at risk (Stroke Association, 2014). A common misconception is that a cerebrovascular accident only occurs in older people, but a cerebrovascular accident can strike anyone at any time (Stroke Association, 2014). Not only do older adults experience cerebrovascular accidents, but young adults and children can also experience them (Stroke Association, 2014). In fact, one in four cerebrovascular accidents in the United Kingdom occurs in patients under the age of sixty-five (Stroke Association, 2014). Manifestations include paralysis or weakness of the face, arm, or leg which may be limited to one or both sides of the body (Stroke Association, 2014). Additionally, confusion or alteration in mental status; difficulty speaking or comprehending speech; visual disturbances; loss of balance, dizziness, difficulty walking; or an abrupt, severe headache may take place (Stroke Association, 2014).