How do cerebral hemorrhage and cerebral aneurysm form? What is subarachnoid hemorrhage?

A hemorrhagic stroke occurs when a blood vessel in the brain ruptures and leaks blood into the spaces between cells in the brain or surrounding tissue. High blood pressure and aneurysms can weaken a blood vessel enough to rupture. There are different types of hemorrhagic stroke, including intracranial hemorrhage (commonly known as brain hemorrhage) and subarachnoid hemorrhage.

1. Intracranial hemorrhage (brain hemorrhage)

An intracranial hemorrhagic stroke is caused by bleeding into the brain from a ruptured blood vessel. The bleeding causes brain cells to die, and the cells in the affected area of ​​the brain stop functioning properly. High blood pressure is the most common cause of an intracranial hemorrhagic stroke.

2. Subarachnoid hemorrhage

Another type of hemorrhagic stroke is called a subarachnoid hemorrhage: A blood vessel ruptures near the surface of the brain, and blood leaks into the space between the brain and skull (the subarachnoid space). Blood pooling in this space puts pressure on brain tissue, causing blood vessels to spasm. This type of stroke is usually caused by a ruptured aneurysm.

3. Brain aneurysm

An aneurysm is a weak spot in the wall of an artery that bulges out to form a thin bag. As it grows, the wall can thin and rupture. If it ruptures, blood can leak into and around the brain.