A stroke, also known as cerebrovascular accident (CVA), is the third leading cause of death in the United States. CVA occurs when brain cells die due to lack of blood. Blood flow to the brain can be disrupted by a ruptured or occluded blood vessel in or around the brain. A CVA caused by ruptured blood vessel is called a hemorrhagic stroke, and an ischemic stroke is due to lack of blood flow. Though somewhat of a dated term, a stroke in which the symptoms last less than twenty four hours has been classically referred to as a transient ischemic attack (TIA). With a TIA the symptoms completely resolve in that time, though these people are at vastly increased risk for having another CVA.
Hemorrhagic strokes usually mean bleeding into the brain and account for 15% of all strokes. People with aneurisms, hypertension or other vascular abnormalities are at an increased risk for having a hemorrhagic stroke. A hemorrhagic stroke is more likely to be fatal than an ischemic stroke. Those who survive a hemorrhagic stroke will have more functional deficits.
Ischemic strokes occur more often than hemorrhagic strokes. There are two types of ischemic strokes, thrombotic and embolic. A thrombus is a clot that develops at the site of atherosclerosis or hardening of the arteries, in this case an artery in the brain. An embolism is a free floating clot in the blood that developed in a blood vessel elsewhere or the heart. It travels through the blood vessels as they narrow until it gets stuck. Nutrient and oxygen rich blood is prevented from getting to cells of the brain.
Carotid artery disease can contribute to ischemic cerebrovascular events. The carotid arteries are located in the neck and supply blood to the brain. Atherosclerosis or hardening of these arteries can cause a gradual narrowing, through thrombus formation restricting blood flow to the brain. These diseased arteries have the potential to form emboli, which can end up in the brain. Surgical procedures are available that can restore normal blood flow to the brain.
The clinical presentation depends upon the location of damaged brain cells and the size of the lesion. Some of the disabilities that can result from stroke include paralysis, cognitive deficits, speech problems, emotional difficulties, depression, pressure sores, pneumonia, continence problems, daily living problems, and pain. If large enough, coma or death can result. During the early stages of an ischemic stroke, clot busting drugs can be used restore blood flow and decrease the extent of the damage. Rehabilitation potential varies depending upon the situation. Evidence exists that with proper training the brain can relearn how to move the body.