Ischemic stroke is caused due to the lack of blood flow to the brain, which, in turn, is caused as a result of blocked artery. This type of stroke is usually associated with kidney disease, heart disease, hypertension, Cushing's disease, and diabetes. Obstruction can be attributed to spinal cartilage, fragment of a tumor, parasites, or even fat. Though the chances are rare, it may also occur as a result of under or overactive thyroid glands.