A stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a "brain attack."
If blood flow is cut off for longer than a few seconds, the brain cannot get blood and oxygen. Brain cells can die, causing lasting damage.
Causes, incidence, and risk factors
There are two major types of stroke:
- Ischemic stroke
- Hemorrhagic stroke
Ischemic stroke occurs when a blood vessel that supplies blood to the brain is blocked by a blood clot. This may happen in two ways:
- A clot may form in an artery that is already very narrow. This is called a thrombotic stroke.
- A clot may break off from another place in the blood vessels of the brain, or from some other part of the body, and travel up to the brain. This is called cerebral embolism, or an embolic stroke.
Ischemic strokes may be caused by a sticky substance called plaque that can clog arteries.
A hemorrhagic stroke occurs when a blood vessel in part of the brain becomes weak and bursts open. This causes blood to leak into the brain. Some people have defects in the blood vessels of the brain that make this more likely. These defects may include:
- Aneurysm
- Arteriovenous malformation (AVM)
High blood pressure is the main risk factor for strokes. the other major risk factors are:
- Atrial fibrillation
- Diabetes
- Family history of stroke
- High cholesterol
- Increasing age, especially after age 55
- Race (black people are more likely to die of a stroke)
Stroke risk is also higher in:
- People who have heart disease or poor blood flow in their legs caused by narrowed arteries
- People who have unhealthy lifestyle habits such as smoking, high fat diet, and lack of exercise
- Women who take birth control pills (especially those who smoke and are older than 35)
Symptoms
The symptoms of stroke depend on what part of the brain is damaged. In some cases, a person may not know that a stroke has occurred. Most of the time, symptoms develop suddenly and without warning. However, symptoms may occur on and off for the first day or two. Symptoms are usually most severe when the stroke first happens, but they may slowly get worse.
A headache may occur if the stroke is caused by bleeding in the brain. The headache:
- Starts suddenly and may be severe
- Occurs when you are lying flat
- Wakes you up from sleep
- Gets worse when you change positions or when you bend, strain, or cough
Other symptoms depend on how severe the stroke is and what part of the brain is affected. Symptoms may include:
- Change in alertness (including sleepiness, unconsciousness, and coma)
- Changes in hearing
- Changes in taste
- Changes that affect touch and the ability to feel pain, pressure, or different temperatures
- Clumsiness
- Confusion or loss of memory
- Difficulty swallowing
- Difficulty writing or reading
- Dizziness or abnormal feeling of movement (vertigo)
- Lack of control over the bladder or bowels
- Loss of balance
- Loss of coordination
- Muscle weakness in the face, arm, or leg (usually just on one side)
- Numbness or tingling on one side of the body
- Personality, mood, or emotional changes
- Problems with eyesight, including decreased vision, double vision, or total loss of vision
- Trouble speaking or understanding others who are speaking
- Trouble walking
Signs and tests
The doctor will do a physical exam to:
- Check for problems with vision, movement, feeling, reflexes, understanding, and speaking. Your doctor and nurses will repeat this exam over time to see if your stroke is getting worse or improving.
- Listen for an abnormal sound, called a "bruit," when using a stethoscope to listen to the carotid arteries in the neck. A bruit is caused by abnormal blood flow.
- Check for high blood pressure
You may have the following tests to help find the type, location, and cause of the stroke and rule out other disorders:
- Angiogram of the head to look for a blood vessel that is blocked or bleeding
- Carotid duplex (ultrasound) to see if the carotid arteries in your neck have narrowed
- Echocardiogram to see if the stroke could have been caused by a blood clot from the heart
- Magnetic resonance angiography (MRA) or CT angiography to check for abnormal blood vessels in the brain
Other tests include:
- Blood tests
- Electrocardiogram (ECG) and heart rhythm monitoring
Treatment
A stroke is a medical emergency. Quick treatment is needed. Call 911 or your local emergency number or seek urgent medical care at the first signs of a stroke.
People who are having stroke symptoms need to get to a hospital as quickly as possible.
- If the stroke is caused by a blood clot, a clot-busting drug may be given to dissolve the clot.
- This treatment must be started within 3 to 4 1/2 hours of when the symptoms first started to be effective.
Other treatments given in the hospital will depend on the cause of the stroke. These may include:
- Blood thinners such as heparin, warfarin (Coumadin), aspirin, or clopidogrel (Plavix)
- Medicine to control symptoms such as high blood pressure
- Special procedures or surgery to relieve symptoms or prevent more strokes
- Nutrients and fluids
- Feeding tube in the stomach (gastrostomy tube)
Physical therapy, occupational therapy, speech therapy, and swallowing therapy will all begin in the hospital.
The goal of treatment after a stroke is to help you recover as much function as possible and prevent future strokes.
Recovery from your stroke will begin while you are still in the hospital or at a rehabilitation center. It will continue when you go home from the hospital or center.
Support Groups
Support and resources are available from the American Stroke Association |www.strokeassociation.org.
Expectations (prognosis)
The outlook depends on:
- The type of stroke
- How much brain tissue is damaged
- What body functions have been affected
- How quickly you get treated
Problems moving, thinking, and talking often improve in the weeks to months after a stroke.
Many people who have had a stroke will keep improving in the months or years after their stroke.
Over half of people who have a stroke are able to function and live at home. Other people are not able to care for themselves.
If treatment with clot-busting drugs is successful, the symptoms of a stroke may go away. However, patients often do not get to the hospital soon enough to receive these drugs, or they cannot take these drugs because of a health condition.
People who have a stroke due to a blood clot (ischemic stroke) have a better chance of surviving than those who have a stroke due to bleeding in the brain (hemorrhagic stroke).
The risk for a second stroke is highest during the weeks or months after the first stroke. The risk begins to decrease after this period.
Calling your health care provider
Stroke is a medical emergency that needs to be treated right away. Call your local emergency number (such as 911) if someone has symptoms of a stroke.
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