Reviewed by Brian R. Robinson, MDA stroke is a "brain attack” (like a “heart attack”) caused either by bleeding in the brain or a loss of blood flow to the brain. Stroke is extremely dangerous and requires immediate emergency medical treatment.
When blood flow in the brain is blocked or disrupted, the brain cells fed by the blocked blood supply begin to die. This leads to severely impaired brain function, and can result in serious brain damage or even death, if the damage is severe enough. There are two major kinds of stroke.
Ischemic stroke occurs when something blocks a blood vessel that supplies the brain. It is estimated that up to 80% of strokes are ischemic strokes. There are two main types of ischemic strokes. Embolic strokes occur when a small blockage, called an embolus, travels to a blood vessel in the brain and becomes lodged there, choking off blood flow. Thrombotic stroke occurs when a blood clot forms in a blood vessel within the brain itself, and becomes large enough to stop blood flow to an area of the brain. This may be due to narrowin of an artery by the build up of fatty plaque or by spontaneous clotting due to a number of different factors.
Hemorrhagic stroke is the result of bleeding in or around the brain. When there is bleeding in the brain, the blood surrounds brain cells, known as neurons, which are normally fed not via the blood directly, but through a thin membrane. When blood surrounds neurons, they cannot work properly. Also, the abnormal bleeding results in insufficient blood flow to other areas, which results in the “starvation” of other neurons. There are two main causes for this type of stroke. The first is the rupture of plaque-filled arteries in the brain, and the second is brain aneurysm, a bulbous stretch of artery caused by a weakening or strain of the arterial wall.
Risk factors for stroke include:
• aging
• family history of stroke
• High blood pressure
• Heart disease
• diabetes
• high cholesterol (LDL over 130, or HDL under 35), or a lifestyle that will lead to high cholesterol
• head and neck injuries
• recent viral or bacterial infection
• sickle cell anemia
• smoking
• high alcohol intake (more than 1-2 drinks a day)
• Drug abuse (cocaine, marijuana, amphetamines, heroin, and anabolic steroids)
• High intake of caffeine, L-asparaginase, or pseudoephedrine (in over-the-counter decongestants)
Additionally, stroke occurs more often in men and people of African American heritage. Stroke is frequently a recurrent problem. There is a much higher risk of stroke in people who have already suffered one.
Stroke is generally diagnosed by a neurological examination. Sometimes symptoms are apparent, but it is necessary to ask the patient – or, if the patient is unconscious or too disoriented to answer questions, a companion – what happened leading up to and during the attack. Blood tests, electrocardiogram, CT scanning, and other tests are usually performed, as well.
Stroke is a severe medical emergency and requires immediate treatment. People who suspect that they or someone around them may be having a stroke should get medical help as soon as possible by dialing 911 and getting to the emergency room right away. Depending on what kind of stroke the patient has had, treatment can vary. Anticoagulants can be helpful in the case of a stroke caused by a blood clot, and they can reduce the risk of such strokes happening again. In the case of hemorrhagic stroke, anticoagulants cannot be used, because they can increase the level of bleeding in the brain. Other drugs may also be administered to protect brain cells and reduce the damage caused by insufficient blood flow that characterizes stroke. There is also a drug called tissue plasminogen activator, or TPA, which can treat ischemic stroke by breaking down blockages and preventing neuron death if administered within a few hours of the stroke’s occurrence.
Since stroke damage can be irreversible once it occurs, the best treatment for stroke is to prevent its occurrence in the first place by eliminating risk factors and maintaining general good health, as well as getting regular neurological exams if the person is in an at-risk group. Surgery called carotid endarterectomy, which involves the removal plaque deposits in the arteries leading to the brain may be necessary in some cases.
Rehabilitation after a stroke can vary in effectiveness, from only mild improvement to a complete recovery. There are several treatments and techniques available for patients who have had a stroke. These include surgery, physical therapy to help patients regain physical ability, psychotherapy to help patients combat the depression and other mental symptoms that occur post-stroke, and speech therapy to help patients regain speech or communication skills. Help for learning disabilities may also be necessary.
