What is a Stroke?
The brain needs a constant supply of blood to work. During a stroke, blood stops flowing to part of the brain. The affected area is damaged. Its functions are harmed or even lost.
What are the Symptoms of a Stroke?
F.A.S.T. is an easy way to remember the signs of a stroke. When you see these signs, you will know that you need to call 911 fast.
F.A.S.T. stands for:
F is for face drooping – One side of the face is drooping or numb. When the person smiles, the smile is uneven.
A is for arm weakness – One arm is weak or numb. When the person lifts both arms at the same time, one arm may drift downward.
S is for speech difficulty – You may notice slurred speech or difficulty speaking. The person can’t repeat a simple sentence correctly when asked.
T is for time to dial 911 – If someone shows any of these symptoms, even if they go away, call 911 immediately. Make note of the time the symptoms first appeared.
Other symptoms of stroke also may include severe headache, dizziness, loss of balance, loss of vision or double vision. Surprisingly, pain is not a frequent symptom of ischemic stroke, although patients with hemorrhagic stroke may complain of severe headache. If you experience any of these symptoms, even if they seem to get better, call 911 right away.
The UC Comprehensive Stroke Center gives patients access to highly skilled physicians from a variety of specialty areas who review cases and discuss the merits of various plans for stroke prevention and treatment.
Types of Stroke
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Most strokes are caused by a blockage in a blood vessel that supplies the brain. This is called an ischemic stroke. It is caused when an artery that supplies the brain is greatly narrowed or blocked. This can be caused by a buildup of plaque. It can also occur when small pieces of plaque or blood clot (called emboli) break off from the blood vessel or heart into the bloodstream. The emboli flow in the blood until they get stuck in a small blood vessel in the brain.
Transient ischemic attacks, or TIAs, are brief episodes of stroke symptoms. TIAs are caused by the temporary interruption of blood flow to the brain. Most TIAs last a few minutes to a few hours. Learn more about treatments for ischemic stroke.
Strokes can also occur if a blood vessel in the brain breaks open (ruptures), called a hemorrhagic stroke. The extra blood presses on those brain cells and can damage them or even cause them to die. Other brain cells die because their normal blood supply is cut off because of high pressure in the skull.
The most common type of hemorrhagic stroke, called an intracerebral hemorrhage, occurs when a small blood vessel within the brain ruptures, leading to a ball of blood (hematoma) in the brain. High blood pressure is a common cause of intracerebral hemorrhage, especially deep in the brain. Older patients may develop a condition called amyloid angiopathy, which makes small blood vessels closer to the brain surface fragile and prone to rupture. Intracerebral hemorrhage may also be caused by an abnormal tangle of blood vessels within the brain, called an arteriovenous malformation (AVM). Although some AVMs never rupture, both known factors (such as an increase in blood pressure) and unknown factors can lead to rupture.
The second type of hemorrhagic stroke is called a subarachnoid hemorrhage. Subarachnoid hemorrhage produces bleeding around the brain, and may be caused by a cerebral aneurysm. A cerebral aneurysm is a balloon-like bulge in the wall of a brain artery. If this bulge tears and bleeds, nearby cells may be damaged. Learn more about treatments for hemorrhagic stroke.
Carotid artery stenosis, or carotid artery disease, is a narrowing of one or both of the two major arteries that run up the neck and carry a large blood supply to the brain. The narrowing is caused by a build-up of plaque on the inside lining of the blood vessel. Plaque build-up (atherosclerosis) is caused when cholesterol, fat and other substances collect in the artery, thereby decreasing the amount of blood flow. When blood flow is decreased, a transient ischemic attack (TIA) or ischemic stroke can occur.
Learn more about diagnosing and treatment of carotid artery stenosis.
An intracranial aneurysm (also called a cerebral aneurysm) is a balloon-like bulge or weakness in the wall of an artery in the brain. As the bulge grows, it becomes thinner and weaker. It can become so thin that the blood pressure within it can cause it to burst or leak. Aneurysms develop due to a weakening in the artery wall and typically occur on larger blood vessels where an artery branches.
Most aneurysms are asymptomatic until they rupture. Ruptured aneurysms release blood into the spaces around the brain called a subarachnoid hemorrhage (SAH). Unruptured aneurysms rarely show symptoms until they grow large or press on vital structures.
A patient may live for years or even decades without knowing he or she has an aneurysm. Risk factors for aneurysm formation include: high blood pressure, atherosclerosis (plaque build-up inside the arterial wall) and smoking, so these risk factors should be avoided or treated. In addition, people with a family history of aneurysms are more likely to have aneurysms.