Stroke: Nursing pathophysiology

A stroke, also known as a cerebrovascular accident, occurs when blood flow to the brain is disrupted, resulting in tissue ischemia and death.

A stroke can be ischemic or hemorrhagic. An ischemic stroke is when there’s an occlusion in an artery in the brain; while a hemorrhagic stroke is when an artery in the brain ruptures and causes blood to leak into the brain tissue.

Now, the brain is the communication and control center of the body, and to maintain neurologic function, all parts of the brain require a steady and consistent flow of oxygen- and nutrient-rich blood. The brain is supplied with blood through the internal carotid arteries and the vertebral arteries. The internal carotid arteries branch off into the middle cerebral arteries and the anterior cerebral arteries, while the vertebral arteries come together to form the basilar artery. The basilar artery then leads into the posterior cerebral arteries. The posterior cerebral arteries, along with the anterior cerebral arteries, internal carotids, and other smaller branched arteries form the circle of Willis.

The circle of Willis is a group of arteries arranged in a circle that allows for collateral blood flow, meaning blood can circulate from one side of the brain to the other if a blockage occurs.

Okay, so with ischemic strokes, blood flow is disrupted by obstruction from a thrombus or embolus. A thrombus is a clot that forms within a vessel, whereas an embolus is when a clot breaks off from one area and travels downstream, lodging in a smaller vessel.

For example, a thrombus can occur from atherosclerotic plaque, where fats build up within a vessel supplying blood to the brain; and an embolus can occur from a blood clot in the atria of the heart due to atrial fibrillation that makes its way into cerebral circulation.