So, we have discussed ischemic and hemorrhagic strokes. Just as a reminder, while you are reading this, an ischemic stroke is when there is a clot causing obstruction in a blood vessel for the brain. There is cerebral thrombosis, where there is a blood clot formed in the vessel in the brain, but there is also a cerebral embolism, where the clot originally formed in another location in the body and a small piece broke off and found its way to the brain's blood vessel. There is also silent cerebral infarction where a blood clot most likely formed from a brain injury. This form of stroke can be a risk factor for future strokes as well.
Hemorrhagic strokes are where a weakened blood vessel ruptures and bleeds into the brain. As the blood accumulates there is an increase in pressure and the surrounding tissue will start to get compressed. There are also two types of hemorrhagic strokes. There are aneurysms and arteriovenous malformations (AVM). An aneurysm occurs with a ballooning of the weakened vessel and can eventually rupture if it is untreated. AVM is where there is a clump of blood vessels with abnormal anatomy/formation. They can rupture as well. Both ischemic and hemorrhagic strokes are also known as CVAs or cerebrovascular accident.
Now, for the other form of stroke that hasn't really been discussed, transient ischemic attack, or TIA. These are commonly called a "mini" or "warning" stroke and are also the result of a clot. In a TIA, instead of permanent blockage, the clot is only temporarily blocking the blood vessel. The symptoms are similar to a CVA, facial asymmetry, unilateral weakness, and speech change, since you are still depriving a brain region of oxygen. They usually only last a maximum of 5 minutes and on average last about 1 minute. Unlike CVAs there is usually no permanent damage to the brain after a TIA. These are highly associated with future stroke. About 1/3 of the people that have a TIA will have a CVA stroke within a year. TIAs are just as important as stroke in the fact that you can get treatment, such as a minor anti-coagulant, to hopefully prevent further strokes in the future. If you are seen by a physician as soon as the symptoms appear you can be assessed within the time window of 6 hours, just in case of it being a CVA not a TIA. There is no way to tell which clots will dissolve and which won't. So for any stroke symptoms it is best to air on the side of caution.
"Types of Stroke." Types of Stroke. N.p., n.d. Web. 05 Oct. 2014. <http://www.strokeassociation.org/STROKEORG/AboutStroke/TypesofStroke/Types-of-Stroke_UCM_308531_SubHomePage.jsp>.
After reading your post I can see TIA's being a very dangerous form of stroke. As we mentioned last week it is very common for patients to experience the more serious forms of stroke and still not come into the hospitals until many hours later. I could easily imagine patients having about a minute of "weirdness" and just forgetting about it a few minutes after. Essentially we could have a fairly large population who may have already had a TIA, not realized it, and are now highly at risk for future strokes. Since most of the general public thinks of stroke as the more severe ischemic/hemorrhagic it could be very useful for TIAs to be more widely talked about. That way when that minute of "weirdness" occurs people could realize "Hey, I might have just had a stroke, I should probably go to the doctor".
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ReplyDeleteI found your post to be very insightful, while in the discussion for the past two weeks and reading the articles, it seemed to me that stoke seemed for the most part to be clumped as one general symptom and syndrome, where as you have shown here it is so far from that. I also liked that the article that you were summarizing brought up TIA as a subcategory of stoke, while some of the articles we discussed did not mention TIA as a part of their considerings, form my experiences working the Neuro Physical therapy, TIAs are frequently seen as a precursor for the stroke patients that we end up seeing in therapym thus playing a large role in taking measures to prevent a future CVA once a TIA has occured.
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