Wednesday, September 24, 2008

Types of Strokes

If cholesterol building up in the arteries is blocking the circulation of blood in any part of the body causing oxygen not to be delivered to the brain, resulting in some cells in the brain to die off and are unable reproduce, then we have stroke. Other strokes happen when a blood vessel in the brain ruptures causing the cells in your brain to be deprived of oxygen in your blood, they die and never come back.
There are 2 types of strokes:
  1. Ischemic stroke caused by a clot or other blockage within an artery leading to the brain.
  2. Hemorrhagic stroke caused by the vessel in the brain rupturing in result of blood leaking into the brain.
1. Ischemic stroke
This is the most common type of stroke accounting for almost 80% of all strokes. The brain depends on its arteries to bring fresh blood from the heart and lungs. The blood carries oxygen and nutrients to the brain, and takes away carbon dioxide and cellular waste. If an artery is blocked then the brain cells may not receive enough oxygen. They then cannot make enough energy and will eventually stop working.
There are 2 types of Ischemic stroke

a)Thrombotic stroke.
If blood clots from the inside of the arteries of the brain, we have thrombic stroke.
Study shows that this type of stroke is responsible for almost 50% of all strokes. The most common problem is narrowing off the arteries in the neck or head. Thrombotic stroke are also sometimes referred to as large-artery strokes. The process leading to thrombotic stroke is complex and occurs over time. Thrombotic stroke might be caused by the arterial walls slowly thickening and hardening as a result of arteries being injured. Such injures signal the immune system to release white blood cells to the site causing stroke. Thrombotic stroke also occurs when the inner wall of arteries were injured in result of less nitric oxide being produced, causing the hardening of the arteries. If the blood clot then blocks the already narrowed artery and shuts off oxygen to part of the brain, we have a thrombotic stroke.

b) Embolic stroke
If blood clotted in other parts of the body's arteries subsequently entering the brain, we have embolic stroke. In this case the clot was formed somewhere other than in the brain itself.
The clot then travels the bloodstream until they become lodged and can not travel any further. This naturally restricts the flow of blood to the brain and results in embolic stroke. An embolic stroke occurs when a blood clot or other particle forms in a blood vessel away from your brain. It is usually caused by a dislodged blood clot that has traveled through the blood vessels until it becomes wedged in an artery. It is also caused by irregular beating in the heart's two upper chambers. This abnormal heart rhythm can lead to poor blood flow and the formation of a blood clot.


2. Hemorrhagic stroke
Hemorrhagic stroke occurs when a blood vessel bursts inside the brain, causing an increase of the fluid pressure on the brain and harms the brain by pressing it against the skull. Hemorrhagic stroke is associated with high blood pressure, which stresses the arterial walls until they break.
There are 2 types of hemorrhagic strokes:

a) Intracerebral hemorrhage:
Intracerebral hemorrhage is internal bleeding that can happen in any part of the brain. Blood may accumulate in the brain tissues itself, or in the space between the brain and the membranes covering it. Most commonly the problem arises in the small arterial inside the brain which have been diseased causing these tiny blood vessels to start to leak. Since the actual source of the bleeding is often small, it can take time for the blood to build up resulting in symptoms of an intracerebral hemorrhage and often increases over minutes or hours. People may not notice the problems associated with bleeding into the brain and ischemic strokes.

b) Subarachnoid hemorrhage
Hemorrhagic strokes that cause bleeding into the fluid filled spaces located deep in the brain are called subarachnoid hemorrhage. Subarachnoid hemorrhage may occur at any age but is most common from age 40 to 65. It is caused by the presence of blood within the subarachnoid space from some pathological processes a result of ruptured aneurysms and bleeding may stop spontaneously. Other causes include vascular malformation, tumors and infection.The most effective treatment is to proceed with microsurgical clipping of the lesion. This stroke causes paralysis of all limbs, unconsciousness and bleeding into the cerebellum produceing typical signs of in coordination with headache and stiffness of the neck.
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