Stroke
Hemorrhagic Stroke
A hemorrhagic stroke, is caused by a blood vessel in the brain that breaks and bleeds into the brain. About 20 percent of strokes are hemorrhagic.
Hemorrhage can occur in several ways.
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One common cause of hemorrhage is a bleeding aneurysm, a weak or thin spot on an artery wall. Over time, these weak spots stretch or balloon out under high arterial pressure. The thin walls of these ballooning aneurysms can rupture and spill blood into the space surrounding brain cells.
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Another way for the occurrence of hemorrhage is when arterial walls break open. Plaque-encrusted artery walls eventually lose their elasticity and become brittle and thin, prone to cracking. High blood pressure or hypertension, increases the risk that a brittle artery wall will give way and release blood into the surrounding brain tissue.
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Finally, hemorrhage can be caused from an arteriovenous malformation (AVM). AVMs are a tangle of defective blood vessels and capillaries within the brain that have thin walls that can easily rupture leading to hemorrhage.
Hemorrhages are classified depending on
the destination of the bleeding from ruptured brain arteries.
The bleeding can either go into the substance of the brain or into the various spaces surrounding the brain.
When a vessel within the brain leaks blood into the brain itself it is called
intracerebral hemorrhage.
When the blood from under the meninges, or outer membranes of the brain bleeds into the thin fluid-filled space that surrounds the brain, it is called
subarachnoid hemorrhage. Here, one of the small arteries within the subarachnoid space bursts, flooding the area with blood and contaminating the cerebrospinal fluid. Since the CSF flows throughout the cranium, within the spaces of the brain, subarachnoid hemorrhage can lead to extensive damage throughout the brain. In fact, subarachnoid hemorrhage is the most deadly of all strokes.
Source: National Institutes
of Health
Caution: If you suspect a
stroke, seek emergency medical treatment immediately. Time is of
essence.
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