Subarachnoid hemorrhage

Cause of subarachnoid hemorrhage

Most hemorrhage is caused by cerebral aneurysms

Subarachnoid hemorrhage is caused when part of one of the arteries that carry blood to the brain through the subarachnoid space ruptures. In around 80–90% of people who develop subarachnoid hemorrhage, the hemorrhage comes from a bulge in an artery called a "cerebral aneurysm." Cerebral aneurysms may be discovered from symptoms if they grow so large that they impede the activity of the surrounding brain; however, in most cases, they remain asymptomatic up until the moment they break. Most cerebral aneurysms form at the point where an artery bifurcates. They are also often seen at the base of the brain, from where the arteries spread out to cover the entire brain.

[ Cause of subarachnoid hemorrhage: cerebral aneurysm ]

More than 90% of subarachnoid hemorrhage is caused by bleeding from a cerebral aneurysm.

Other causes of subarachnoid hemorrhage include a split in the wall of a cerebral blood vessel (cerebral artery dissection), causing hemorrhage, rupture of a blood vessel due to injury, hemorrhage from a deformity of the cerebral vessels, called an cerebral arteriovenous malformation, or when a blood or organ disorder means that hemorrhage is difficult to stop. The cause may not always be possible to identify, even after a variety of tests have been performed.

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