Posted: April 11th, 2022

Stroke/ Cerebrovascular Disease

Stroke/ Cerebrovascular Disease.

Cerebrovascular disease, commonly known as stroke, represents a group of conditions and disorders that impact blood vessels in the brain, causing an abrupt disruption of blood supply to the brain cells and tissues. This disruption can occur due to various factors, including blood clots, vessel ruptures, or narrowing of arteries. When deprived of oxygen and nutrients, brain cells start to die immediately. The speed at which this occurs underscores the critical nature of rapid medical intervention in stroke cases. If the deprivation occurs for an extended period, permanent brain damage can occur. The severity and location of this damage can significantly impact a person’s quality of life and functional abilities. The Centres for Disease Control and Prevention (CDC) ranks stroke as the fifth leading cause of death in America, with about 795,000 fatalities a year. This staggering statistic highlights the urgent need for improved prevention strategies and treatment options.

Types of Stroke
There are two major types of stroke, ischemic and hemorrhagic stroke. Understanding the differences between these types is crucial for proper diagnosis and treatment. Ischemic stroke is the most common type of stroke, accounting for about 80% of all stroke cases in America. This high prevalence makes ischemic stroke a primary focus in stroke research and treatment development. It occurs when a clot in the brain artery abruptly blocks the flow of blood to the brain. The blockage can be caused by a thrombus (a clot that forms locally) or an embolus (a clot that travels from elsewhere in the body). Hemorrhagic stroke occurs when blood vessels in the brain burst, causing bleeding and hemorrhaging in the brain tissues. This type of stroke, while less common, often results in more severe outcomes due to the pressure exerted on brain tissues by the accumulating blood. Hemorrhagic stroke can further be categorized into intracerebral and subarachnoid hemorrhages. The distinction between these subtypes is important for determining the most appropriate treatment approach. In an intracerebral hemorrhage, blood pours directly inside the brain tissues causing compressions. This type of hemorrhage often results from long-standing hypertension or blood vessel abnormalities. However, in subarachnoid hemorrhage, bleeding occurs in the membrane surrounding the brain. Subarachnoid hemorrhages are frequently caused by ruptured aneurysms or arteriovenous malformations.

Signs and Symptoms of a Stroke
Symptoms vary depending on the location of the blockage and the extent of the impact. This variability can sometimes make stroke diagnosis challenging, especially in cases with atypical presentations. However, typical signs and symptoms of stroke include unexpected body paralysis or numbness accompanied by severe headache, blurred vision, nausea, dizziness, slurred speech, confusion, and loss of balance when walking. Healthcare professionals often use the acronym FAST (Face drooping, Arm weakness, Speech difficulty, Time to call emergency services) to help the public recognize and respond to stroke symptoms quickly. Stroke often attacks one side of the body. This unilateral presentation is due to the fact that each hemisphere of the brain controls the opposite side of the body.

Causes, Risk Factors, and Complications
Stroke can develop from various causes, including arteriosclerosis, which is the narrowing of arteries. This narrowing process often occurs over many years, emphasizing the importance of long-term cardiovascular health management. Narrowed arteries increase the pressure of blood flow, causing a rapture. The rupture can lead to hemorrhagic stroke or create conditions favorable for clot formation. Stroke can also result from thrombosis or an embolic arterial clot where a blood clot occurs in an artery that supplies blood to the brain. These clots can form due to various factors, including atrial fibrillation, a common heart rhythm disorder.

All strokes damage brain tissues with the possibility of irreversible disability or death. The extent of this damage depends on factors such as the duration of oxygen deprivation and the specific brain regions affected. When the blood flow to the brain is temporarily disrupted, a minor stroke called Transient Ischemic Attack (TIA) occurs. While less severe, TIAs are important warning signs that should not be ignored. TIA has short-lasting symptoms that resolve in less than one hour. However, the severity of a stroke is determined by the part of the brain affected and the deprivation period. The brain’s plasticity allows for some recovery and adaptation after stroke, but the degree of recovery can vary widely among individuals. Risk factors include unhealthy diet, lack of exercise, alcohol and drug abuse, and underlying conditions like blood pressure, diabetes, and sickle cell. Many of these risk factors are modifiable, highlighting the potential for stroke prevention through lifestyle changes and proper management of chronic conditions.

Diagnosis and Treatment of Stroke
Because stroke attacks are unpredictable, diagnosis entails medical analysis of symptoms before the attack. Rapid diagnosis is crucial, as the effectiveness of many stroke treatments depends on how quickly they are administered. The medical history of the patient, coupled with physical and medical examination, also helps in diagnosis. Advanced imaging techniques such as CT scans and MRIs play a crucial role in determining the type and extent of the stroke. Treatment for stroke depends on the type of stroke. This differentiation is critical, as treatments that are beneficial for one type of stroke can be harmful for the other. Ischemic stroke is commonly treated using blood thinners, which help dissolve the clot, restoring blood flow. In some cases, more aggressive treatments such as mechanical thrombectomy may be employed to physically remove the clot. For hemorrhagic stroke, drugs that lower blood flow pressure in the brain caused by bleeding are used. These medications aim to prevent further bleeding and reduce intracranial pressure. However, in emergencies, surgery may be used to remove the clot and repair the ruptured vessels. Post-stroke care, including rehabilitation therapies, is crucial for maximizing recovery and preventing future strokes.

References
American Diabetes Association. “9. Cardiovascular disease and risk management.” Diabetes care 40.Supplement 1 (2017): S75-S87.

Martins, Bárbara, et al. “Data Mining for Cardiovascular Disease Prediction.” Journal of Medical Systems 45.1 (2021): 1-8.

Frontera, Jennifer A., et al. “Risk factors, mortality, and timing of ischemic and hemorrhagic stroke with left ventricular assist devices.” The Journal of Heart and Lung Transplantation 36.6 (2017): 673-683.

Khaku, A. S., & Tadi, P. (2022). Cerebrovascular Disease. In StatPearls. StatPearls Publishing.

Imoisili, O. E., Lundeen, E. A., Park, S., Friedman, D. J., Tsai, A. Y., & Jackson, S. L. (2024). Prevalence of Stroke — Behavioral Risk Factor Surveillance System, United States, 2011–2013 and 2020–2022. MMWR. Morbidity and Mortality Weekly Report, 73(20), 545-550.

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Tags: Cerebrovascular Disease, Stroke Diagnosis and Treatment, Stroke Risk Factors, Stroke Types