A stroke, or brain attack, is caused by the sudden loss of blood flow to the brain or bleeding inside the head. Each can cause brain cells to stop functioning or die. When nerve cells in the brain die, the function of body parts they control is harmed or lost. Depending on the part of the brain affected, people can lose speech, feeling, muscle strength, vision, or memory. Some people recover completely; others are seriously disabled or die.
You can reduce your chances of death or disability if you recognize the signs of stroke and get immediate medical help. Quick medical attention and treatment can save lives. It can also prevent more serious, long-lasting problems. People who are suffering a stroke must get immediate medical care. It is very important they get to a hospital within 60 minutes of the onset of a stroke. Time is of the essence.
Stroke risk increases sharply with age, doubling every decade after the age of 55. However, stroke can occur at any age. About 28 percent of those who have a stroke are under 65 years old. Men have slightly more strokes than women. Strokes claim the lives of more women than breast cancer. And people with a family history of stroke and heart disease have an increased stroke risk.
There are also very important risk factors that often can be controlled:
- Monitoring and reducing high blood pressure
- Limiting tobacco use
- Managing cholesterol levels
- Maintaining a healthy weight
- Controlling diabetes
See your doctor for help in addressing these risk factors.
Types of Stroke
The brain is affected by two types of stroke, "ischemic" and "hemorrhagic."
Eighty percent of all strokes are ischemic. Ischemic strokes can be caused by narrowing of the large arteries to the brain. This is also called "atherosclerosis." Ischemic strokes include:
- Embolic: Clots travel from the heart or neck blood vessels and lodge in the brain, sometimes due to an irregular heartbeat, called "atrial fibrillation"
- Lacunar: Small vessels in the brain are blocked, often due to high blood pressure or diabetes damage
- Thrombotic: Clots form in the brain blood vessels, often due to "arteriosclerosis," or hardening of the arteries
When blood cannot get to the brain cells, they die within minutes to a few hours. Doctors call this area of dead cells an "infarct."
The lack of normal blood flow to brain cells sets off a chain reaction called the "ischemic cascade." Over hours, this endangers brain cells in an increasingly larger area of brain where blood supply is reduced but not completely cut off. Quick medical treatment offers the best chance of rescuing this area of brain cells, called the "penumbra."
Hemorrhagic strokes involve bleeding into or around the brain, including:
- Subarachnoid: Weak spots on brain arteries, called "aneurysms," burst and blood covers the brain.
- Bleeding into the brain: Blood vessels in the brain break because they have been weakened by damage due to high blood pressure, diabetes, and aging.
Stroke symptoms may not be as dramatic or painful as a heart attack. But the results can be just as life-threatening. Stroke is an emergency. Get medical help immediately and know when the symptoms started. Common symptoms include:
- Sudden numbness or weakness of face, arm, or leg, especially on one side of the body.
- Sudden confusion, trouble speaking or understanding speech.
- Sudden difficulty seeing in one or both eyes.
- Sudden trouble walking, dizziness, loss of balance or coordination.
- Sudden severe headache with no known cause.
Call 1066 immediately if you or someone you know experiences any of the above warning signs. Write down the time the symptoms started. Sometimes these warning signs last for only a few minutes and then go away. Even if this happens, or if you think you are getting better, call for help.
The neurologist or emergency doctor must examine you to understand your condition and find out what caused the stroke. Diagnostic tests to determine treatment could include:
- Neurologic exam
- Brain imaging tests (CT, or computerized tomography scan; MRI, or magnetic resonance imaging) to understand the type, location, and extent of the stroke.
- Tests that show blood flow and bleeding sites (carotid and transcranial ultrasound and angiography).
- Blood tests for bleeding or clotting disorders.
- EKG (electrocardiogram) or an ultrasound examination (echocardiogram) of the heart to identify cardiac sources of blood clots that could travel to the brain.
- Tests that measure mental function.
Immediate medical care is important. New treatments work only if given within a few hours after a stroke begins. For example, a clot-busting drug must be given within three hours.
Once the doctor completes the diagnostic tests, the treatment is chosen. For all stroke patients, the aim is to prevent further brain damage. If the stroke is caused by blocked blood flow to the brain, treatment could include:
- T P A (tissue plasminogen activator), a clot-busting drug that is injected within three hours of the start of a non-bleeding stroke.
- Drugs that thin the blood, including anticoagulants (warfarin) and antiplatelet medications (aspirin or ticlopidine); a combination of aspirin and sustained release dipyridamole.
- Surgery that opens the insides of narrowed neck blood vessels (carotid endarterectomy).
If bleeding causes the stroke, treatment could include:
- Drugs that maintain normal blood clotting.
- Surgery to remove blood in the brain or decrease pressure on the brain.
- Surgery to fix the broken blood vessels.
- Blocking off bleeding vessels by inserting a coil.
- Drugs that prevent or reverse brain swelling.
- Inserting a tube into a hollow part of the brain to lower pressure.
After a stroke, a person may have some disability. The disability depends on the size and location of the stroke. The right side of the brain controls the left side of the body; in right-handed individuals it is important for attention and visual-spatial skills. The left side of the brain controls the right side of the body; in right-handed individuals (and 50 percent of left-handed people) it controls language speaking and understanding. Language disorders are also called "aphasias."
Rehabilitation helps regain functions lost from damage due to stroke. During rehabilitation, most people will get better. However, many do not recover completely. Unlike skin cells, nerve cells that die do not recover and are not replaced by new cells. However, the human brain is adaptable. People can learn new ways of functioning, using undamaged brain cells.
This rehabilitation period is often a challenge. The patient and family work with a team of physical, occupational, and speech therapists, along with nurses and doctors. Most of the improvement will take place in the first three to six months of the process. But some people can make excellent progress over longer periods.