Job Hazards

Ischemic Stroke

An ischemic stroke occurs when an artery carrying fresh blood from the heart and lungs to the brain is clogged. Oxygen and nutrients are carried via the bloodstream to the brain, while carbon dioxide and cell waste is ushered away from the brain. Once an artery is blocked, the neurons, or brain cells, cannot produce sufficient energy to continue functioning. If the blockage continues for more than a few minutes, the neurons could die. For this reason, emergency medical care is extremely vital.

Causes of Ischemic Strokes

Various diseases can lead to an ischemic stroke. One of the most common causes of ischemic strokes is atherosclerosis, which causes the arteries in the neck or head to narrow as a result of cholesterol deposits lining their interior. If the arteries become too narrow, blood cells may gather and begin to clot. There are two kinds of blood clots:

• Thrombosis: This type of blood clot blocks the artery in the same spot as they are formed.
• Embolism: This type of blood clot is displaced from the wall of the artery and can become trapped in arteries closer to the brain.

Blood clots in the heart also may cause a stroke. This can be due to an irregular heartbeat (e.g., atrial fibrillation), heart attack, or anomalies of the heart valves. Additional causes of ischemic stroke include narcotics, traumatic injury to blood vessels within the neck, or other blood clot abnormalities.

When diseased or damaged cerebral arteries develop a blood clot that grows large enough to prevent blood flow, a thrombotic stroke occurs. Also known as cerebral thrombosis, half of all strokes are caused by this condition. This term can be further divided into two categories depending on the area of the brain where the blockage occurs. Large-vessel thrombosis occurs when the blockage impacts one of the brain's larger arteries, such as the carotid or middle cerebral. Small-vessel thrombosis affects at least one of the tinier arteries that reach deeper into the brain. This second type of thrombosis is referred to as lacuner stroke.

An embolic stroke is caused by a blood clot inside an artery as well, but the clot originates in a section of the body besides the brain. Usually starting in the heart, the clot will navigate the bloodstream until it reaches a point too narrow to pass. As a result, an ample amount of blood is prohibited from reaching the brain, resulting in sudden physical and neurological impairment.