What is a stroke and how does it occur?
A stroke occurs when a portion of the brain dies due to a lack of oxygen. Usually an artery that supplies the brain with oxygen carrying blood has been damaged or blocked by a clot (Ischemic Stroke); this is how most strokes occur. The other, small percentage, happens when an artery in the brain bursts (Hemorrhagic Stroke).
In an Ischemic stroke a blood clot or fatty deposits on a vessel wall, are formed in the heart or neck and are moved/swept upwards to the brain where it then blocks an artery. Protective mechanisms of the brain immediately begin to fight back by raising the blood pressure in hopes of clearing the artery. In the meantime, cells around the brain are beginning to shut down due to a lack of oxygenated blood. This occurs in 85% of strokes.
With a Hemorrhagic stroke, the problem is a little more disastrous. In this case, an artery is ruptured, preventing normal flow of blood and allowing it to leak into the brain tissue. This causes the brain to swell. If the swelling is continuous, the skull can crush the centers for consciousness and breathing. 13% of strokes are hemorrhagic.
Symptoms or Warning signs of a stroke
A simple acronym used to determine if someone, or yourself, is having a stroke is called FAST. Facial weakness: ask the individual to smile. If one side of their face seems to droop, then it is one of the beginning onsets of a stroke. The next step is Arm and leg weakness. Ask him or her to then raise both arms. If they have trouble bringing one of their arms up, it is another symptom. Speech problems is the next big one. Ask the person to repeat a simple sentence that, in any other circumstances, they would have no problem completing. For example, "It's a cloudy day." The last step in FAST is Timing. Timing is critical: TIME IS BRAIN. There is only a small window of time that the most effective treatment for a stroke can be administered; three hours of the onset of stroke. The drug administered is tPA, a de-clotting agent. However, there is a concern with tPA. In 6% of cases, tPA causes bleeding in the brain and can be fatal. This is dangerous, especially if it was found that the patient had not even had a stroke. There is no easy way to determine if someone is having a stroke. The best way is thorugh an M.R.I and the confirmation of a neurologist. But since both are unlikely to be found on hand, the responsibility lies with the emergency room doctor.
Risk Factors: The controllable and the out of hand
Stroke risk factors that are uncontrollable have to do with increasing age, male sex, race (especially African Americans), and family history of stroke. There are, however, factors that can be modified through medical treatment and lifestyle changes. These include high blood pressure, cigarette smoking, diabetes, obesity, Aspirin, high blood cholesterol (a leading factor in stroke), and heart disease. You can also reduce your risk by conducting annual physicals with your physician, keeping a healthy diet, being aware of your family history, and maintaining a healthy weight.
**If your interested in learning more about stroke, I found a pretty awesome video link. It won't take up much of your time and your not obligated to watch it :)
Crucial Facts about Stroke Video:
http://video.on.nytimes.com/?fr_story=1597c973a409a01c13d05376ef6312ad307251c1
References:
American Stroke Foundation- http://www.americanstroke.org
The Stroke Awareness Foundation- http://www.strokeinfo.org/
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4 comments:
I really like your video. Very informative.
I have a some questions about the TPA treatment the doctor talks about in the video. Does the treatment actually reverse the damage done by the stroke? Or does it just prevent further damage from occurring?
I thought that once the clot happened in the brain and the stroke occurred, the brain became damaged immediately. And as the clot remained in the brain longer, the damage to the brain became more extensive. The longer it went untreated the more serious the damage is, but there is always some damage.
Am I wrong? Is it possible that if you remove the clot within the 3hr window of treatment there is no damage? Or does it just increase the odds of survival if a person is treated during that time?
tPA, Tissue plasminogen activator, is a thrombolytic agent (clot busting drug). It dissolves clots caused by strokes and is the only drug approved by the FDA for the treatment of ischemic stroke.
I don't think tPA reverses the damage done by a stroke. It actually reduces the amount of damage due to the effects of stroke and also reduces permanent disability that can occur.
tPA does need to be administered with a three hour time frame from the onset of symptoms in order to have any effect at all. If given during that time, I don't think it stops any damage from happening, there will always be a minimal amount of damage caused by lack of oxygen to the brain.
Let me know if that answers your questions. If not, I will further explain tPA as much as possible.
I was watching the news the other day and a 13 year old boy had a stroke. He is doing fine, however he is waiting to have heart surgery. What type of heart problems would cause a stroke? I am wondering if it would be valvular, causing turbulent blood flow in the heart, creating a clot?
Here is the article:
http://www.kvoa.com/Global/story.asp?s=9110054
About the boy with a stroke, the article isn't helpful about cause. But you are right about turbulence. In older people stroke often follows on abnormal rhythms, like atrial fibrillation, which allows clot to form. But why is the left atrium fibrillating? Sometimes, because it's exhausted from pushing against a scarred bicuspid valve for a long time.
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