Stroke – a Cerebrovascular Accident
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Table of Contents
Definition
General Information
Types
Ischemic Stroke
Hemorrhagic Stroke
Stroke Warning Signs
Risk Factors
Treatable Risk Factors
How a CVA is Diagnosed
Medical Treatment
Emergency and Rehabilitation
Prevention and Prognosis
Effects of Stroke
Common Problems and Complications
Statistics
Cost Of Stroke to the United States
Final Data for 2000
Key Terms
Definition
A cerebrovascular accident more commonly known as a stroke or brain attack is the term used to describe the sudden death of brain cells in a localized area due to inadequate blood flow. In order to woke the brain needs a constant supply of oxygen and nutrients. This supply is carried to the brain by blood through the arteries. If part of the brain is deprived of blood for longer than a few seconds brain cells can die. A stroke causes loss of function, sometimes permanently, in the part of the body that is controlled by the damaged part of the brain.
General Information
A stroke occurs when blood vessels in the brain burst spilling blood into the space surrounding brain cells, or when the blood supply to part of the brain is blocked thus a stroke is known as a cerebrovascular accident (ÐЎЧcerebroÐÐŽÐÐ refers to a part of the brain ÐЎЧvascularÐÐŽÐÐ refers to the blood vessels and arteries.) In the same way that a person suffering a loss of blood flow to the heart is said to be having a heart attack, a person with a loss of blood flow to the brain or sudden bleeding in the brain can be said to be having a ÐЎЧbrain attack.ÐÐŽÐÐ
Blood flow to the brain tissue can be hampered in two ways, one the vessel ruptures, causing blood to leak into the brain. Hemorrhagic is the term used to describe bleeding into the brain or the spaces surrounding the brain. In the second the vessel clogs within Ischemic is the term used to describe the blockage of blood flow and loss of oxygen and nutrients for brain cells.
Blood clots are the most common cause of artery blockage. The process of clotting is necessary and beneficial through out the body because it stops bleeding and allows repair of damaged areas of arteries or veins. However when blood clots develop in the wrong place within the artery they can cause devastating injury by interfering with the normal flow of blood. Clots most often form due to Atherosclerosis. In Atherosclerosis cholesterol containing fatty deposits (plaques) build up over time on the inside of the artery walls. This accumulation narrows, hardens, and roughens the inside surface of the arteries. Turbulent blood flow around deposits of plaques trigger clot development.
Ischemic Strokes
A Ischemic stroke occurs when a blood clot blocks an artery either in the brain itself or in the neck. These blockages stem from three conditions; the formation of a clot within a blood vessel of the brain or neck, called Thrombotic; The movement of a clot from another part of the body such as the heart to the neck or brain called embolism; or a severe narrowing of an artery in or leading to the brain, called stenosis.
Thrombotic stroke occurs when a blood clot forms in one of the cerebral arteries that stays attached to the artery wall until it grows large enough to block blood flow.Cerebral Thrombus occurs most often at night, or early in the morning. In most instancies the underlying cause is Atherosclerosis. Cerebral thrombosis is often preceded by a transient ischemic attack, or TIA, sometimes called a ÐЎЧmini-stroke.ÐÐŽÐÐ In a TIA, blood flow is temporarily interrupted, causing short lived stroke like symptoms.This kind of Ischemic stroke accounts for 60% of a stroke cases.
Embolic stroke is another common form of Ischemic stroke. It can occur when a clot, or small piece of plaque formed elsewhere in the circulatory system breaks free.This free roaming clot travels through the bloodstream until it reaches vessels too small to let it pass. This kind of stroke accounts for 20% of all strokes. In most instancies the underlying case is Atrial Fibrillation. A disorder of the heart beat. The heart doesnÐЎЦt completely empty the blood from the chambers. This stagnant blood forms clots that break off and inter the circulation. Atrial Fibrillation is a factor in about 15% of Embolism stroke.The risk of a stroke from atrial fibrillation can be dramatically reduced with daily use of anticoagulant medication.
Hemorrhagic Strokes
Hemorrhagic stroke occurs when a blood vessels in the brain leaks or ruptures. Bleeding from the ruptured brain artery can either go into the substance of the brain or into the various spaces surrounding the brain. The two types of hemorrhagic stroke are Intracerebral and Subarachnoid hemorrhagic.
Intracerebral hemorrhagic stroke occurs when vessels within the brain leaks blood into the brain itself. It often happens without warning. This type of stroke represents about 10% of all strokes. The most common cause is uncontrolled high blood pressure or (Hypertension.) Hypertension can cause small arteries inside the brain to become brittle and susceptible to cracking and rupture. Less often it may result from a blood vessel defect present since birth.
In a subarachnoid hemorrhage, bleeding occurs within the space between the brain and the skull. This type of stroke accounts for about 7% of all strokes. A subarachnoid hemorrhage is often signaled by a sudden thunderclap headache thats more severe than any you have ever felt. About half of all people who experience a subarachnoid hemorrhage die. Half of those who survive are left permanently disabled. In fact, subarachnoid hemorrhage is the most deadly of all strokes. The most common cause of subarachnoid hemorrhages is a ruptured aneurysms.