Long Summary
There are two main types of stroke: ischemic and hemorrhagic. Ischemic strokes, which are much more common, occur when an artery is blocked, causing reduced blood flow to parts of the brain and leading to tissue damage. Transient ischemic attacks are brief ischemic events where symptoms resolve within 24 hours without lasting damage. Understanding brain anatomy is key to recognizing how strokes impact different functions, as the brain consists of regions such as the cerebrum, cerebellum, and brain stem, each responsible for various motor, sensory, and autonomic functions.
The brain receives blood supply from multiple arteries that form the circle of Willis, enabling collateral circulation and offering alternative blood routes if one artery is blocked. Ischemic strokes happen when blood flow drops below tissue needs, usually due to plaque buildup (atherosclerosis) or emboli traveling from other parts, particularly the heart. Plaques can rupture, triggering clot formation that acutely blocks arteries. Embolic strokes arise when clots from the heart or other vessels lodge downstream in smaller arteries. Lacunar strokes involve small deep arteries and are common in conditions like hypertension and diabetes.
Brain tissue around the ischemic core, called the penumbra, can survive temporarily with collateral blood flow but is at risk unless blood supply is promptly restored. Cell injury begins within minutes of ischemia, leading to edema, cell death, and subsequent inflammation that can cause dangerous brain swelling. The skull's fixed volume means swelling can displace brain tissue, potentially compressing vital centers in the brain stem and threatening vital functions like breathing and consciousness.
Stroke symptoms vary depending on the affected brain area, with common signs summarized by the acronym FAST: facial drooping, arm weakness, speech difficulties, and time to act. Diagnostic imaging, including CT and MRI, alongside angiography, helps identify stroke location and severity. Treatments focus on quickly restoring blood flow using clot-busting drugs like tissue plasminogen activator or mechanical clot removal devices. Long-term management includes controlling risk factors such as smoking, blood pressure, cholesterol, and diabetes to prevent recurrent strokes. Surgery may be needed to remove severe arterial plaques or place stents to maintain artery openness.
This comprehensive approach to understanding ischemic stroke—covering anatomy, pathology, symptoms, diagnosis, treatment, and prevention—highlights the urgency of recognizing stroke signs and responding quickly. Fast, effective intervention can protect brain tissue, reduce disability, and improve outcomes for stroke patients worldwide.
