Are all strokes caused by a blockage of blood flow to the brain?
No. Most but not all strokes occur due to decreased flow of oxygen-rich blood to the brain (a condition known as ischemia). This lack of blood flow can be caused by a partial or complete occlusion of a blood vessel by plaque formation (atherosclerosis). Blood vessel occlusions can also occur when a piece of plaque or a blood clot breaks off and flows downstream in a blood vessel to a smaller blood vessel, occluding the blood flow to the brain. Other types of strokes can occur due to a dilated blood vessel (aneurysm) rupturing subsequently decreasing blood flow to the brain. Blood leaking from such a ruptured vessel creates additional complications to this type of stroke due to the blood leaking out putting pressure on the brain. Copyright 2006 Cardiodiagnostics of Colorado Springs, Inc.
