Strokes

Strokes occur as a result of reduced or of total blockage of the blood vessels that carry oxygenated blood to different parts of the brain.  They are mostly caused by blood clots and atherosclerosis (which causes the arteries to harden).  Blood-clots can form as the accumulation of plaque or fatty deposits and cholesterol in the blood vessels.

 

Photo from: http://www.stroke.org/site/PageServer?pagename=explainingstroke

There are two different kinds of strokes.  The first is the most common type and it includes Ischemic Strokes, which composed of two types of strokes.  The first type of Ischemic Strokes is called an embolic stroke, and the second type of Ischemic Stroke is called a thrombotic stroke, which is also composed of 2 different types of strokes, and the second type is called a Hemorrhagic stroke.  As a result of these types of strokes, you can lose or restrict certain functions in your body.  Embolic Strokes are caused when a blood clot forms is a blood vessel or artery and eventually dislodges from the wall of the blood vessel, and travels through the bloodstream to your brain, where the clot blocks the flow of blood.  Thrombotic Strokes are caused by blockages of the arteries that carry blood to the brain (these types to not travel).  This type of stroke is split into two categories; Large Vessel Thrombosis, and Small Vessel Disease (also referred to as a Lacunar Infarction).  Large Vessel Thrombosis takes place in large arteries, and is caused by continual atherosclerosis, and the rapid development of blood clots.  Small Vessel Disease is caused when the flow of blood blocks to a small blood vessel. This type can also be caused by high blood pressure.  The last type is called a Hemorrhagic Stroke, which come is two different forms called subarachnoid and intracerebral.  They are caused by aneurysms (easily broken parts of a blood vessel wall) that are located in near the surface of the brain and can spill into the protective fluid that encases the brain and the continued stresses of high blood pressure respectively.

Strokes can be treated by thrombolytic drugs which dissolve clot before they can cause major harm.  TPA is an enzyme found in the body.  It converts the enzyme plasminogen into the plasmin enzyme to dissolve blood clots (for victims of ischemic strokes).  Another method is called MERCI Retrieval System.  This treatment can literally grab clots and pull them out the blood vessel to restore normal blood flow.  This treatment can also be used at any stage of the stroke.  Another treatment is called the Penumbra System, which uses suction to suck out clots that are in the brain even after an ischemic stroke.

            Strokes can be prevented by lowering high blood pressure (good blood pressure scores are usually lower than 120/80, managing atrial fibrillation (which affects how your heart functions through irregular heartbeats), stopping smoking drastically reduces the chance of getting a stroke, by drinking in moderation, lowering cholesterol (remember that clots can form from cholesterol), manage your blood sugar, consume less salt and fats, and exercise often.


Sources:


http://www.stroke.org/site/PageServer?pagename=explainingstroke
http://www.stroke.org/site/PageServer?pagename=treatment
http://www.jneurosci.org/content/22/6/2125.full.pdf