The underlying pathology of a cerebral vascular accident, or stroke, is usually heart or blood vessel disease, most notably high blood pressure, atherosclerosis and coronary artery disease, according to the Internet Stroke Center. An abnormal lipid profile and high cholesterol also contribute to strokes by increasing a person's susceptibility to blood clots.
When a person has atherosclerosis and high cholesterol, fatty deposits occur inside blood vessel walls. Over time, these deposits cause injury to the blood vessels, which, in turn, results in the formation of blood clots. When these clots form in the blood vessels inside the brain, they can block blood flow, causing tissue injury and tissue death. Doctors call this an ischemic stroke, according to Dr. Joel Fuhrman, M.D.
Another cause of ischemic stroke is a brain embolism, which occurs when a blood clot forms in another part of the body and then travels through the bloodstream to the brain, explains Medical News Today. About 30 percent of strokes are the result of an embolism. In these cases, the underlying pathology is often atherosclerosis and heart disease. However, clotting abnormalities, infections, cancer, obesity and pregnancy also increase the chances of developing a blood clot and an embolism.
Less commonly, strokes occur due to bleeding in the brain, a condition doctors call a hemorrhagic stroke. These often occur due to a weakened area in a blood vessel, which is known as an aneurysm. In some females, a defect in collagen leads to multiple small aneurysms at the branching points of the cerebral arteries, which eventually tear and bleed, explains Medical News Today.