The Medical Minute: Stroke awareness
A stroke is sudden brain injury caused by a sudden vascular (blood vessel) compromise. There are two major types of strokes. An ischemic stroke occurs when blood flow to a part of the brain is blocked by clot or other debris. This is the most common type, comprising approximately 85 percent of all strokes. The other type, hemorrhagic stroke, occurs when a blood vessel or aneurysm ruptures and blood spreads in and around the brain. Strokes can be mild, or can be quite disabling, even fatal, depending on the brain area involved and the type of stroke.
Stroke symptoms occur suddenly and without warning. The most common symptom is weakness or numbness, often on one side of the body or face. Other common symptoms include slurred or abnormal speech, confusion, visual loss or double vision, dizziness, balance problems, and severe headache. The "worst headache of my life" is commonly associated with a brain hemorrhage. The term "FAST" (Face, Arm, Speech, Time), refers to facial droop, arm weakness, slurred speech, and urgency of time. This memory tool is also a reminder to call 9-1-1 immediately if a stroke is suspected.
There are acute treatments available for both types of strokes. These treatments are time based, so earlier recognition and treatment will lead to a better outcome ("time lost is brain lost"). For ischemic strokes, the FDA-approved clot buster intravenous t-PA must be administered within 3-4.5 hours of stroke onset. The use of IV t-PA is associated with an approximately 40 percent chance of very good outcome (near-normal or normal state) at 90 days post-stroke. There also are catheter-based procedures to remove a clot from blocked brain arteries within several hours of the stroke that have been shown to significantly improve outcomes. For brain hemorrhages, there are neurosurgical approaches and catheter-based approaches. Early treatment can significantly decrease brain swelling and reduce recurrent brain bleeding and is associated with better clinical outcomes.
Many strokes -- up to 80 percent -- are preventable. Knowing the common risk factors is critical. These include high blood pressure, uncontrolled diabetes, abnormal cholesterol levels, smoking, alcohol abuse, obesity, carotid artery disease, atrial fibrillation (an irregular heart beat) and obstructive sleep apnea. For women, frequent migraine headaches (particularly with auras), birth control pill use, and advancing age (30-40s), are associated with increased stroke risk. These are all modifiable risk factors, with behavioral changes like healthy diet and exercise, or various medication therapies. For symptomatic carotid artery stenosis, one should consider a surgical intervention, called carotid endarterectomy, and, in select cases, carotid artery stenting. Anyone with at least one of these risk factors should discuss strategies for management with their primary care physician.
Another important risk factor for stroke is a transient ischemic attack, TIA, or "mini-stroke," which occurs 25 percent of the time before a stroke occurs. The symptoms are the same as a stroke, but resolve in less than an hour. Up to 20 percent of individuals who experience a TIA will later suffer a stroke. A TIA is a great window of opportunity to prevent a stroke, so prompt medical attention is needed.