What happens during a brain hemorrhage?

If a brain aneurysm ruptures or an artery that passes over the surface of the brain bursts, blood flows into the fluid-filled space around the brain. Doctors call this area the "subarachnoid space." Bleeding into this space is called a subarachnoid hemorrhage.

Blood can then quickly spread in this space and put pressure on the whole brain. This means that even parts of the brain that aren't very close to the bleeding blood vessel are damaged. The bleeding quickly causes a severe headache. Left untreated, it often leads to unconsciousness and life-threatening complications like an irregular heartbeat and respiratory arrest (where you stop breathing effectively, or at all).

The brain damage can cause long-term or permanent problems in everyday life, or lead to the need for nursing care – for instance because of speech problems or paralysis.

If an artery in the brain bleeds directly within the brain tissue, it is known as an intracerebral hemorrhage. This type of stroke is often simply called a “brain hemorrhage." The blood that flows out presses against the tissue from the inside and pinches off other blood vessels in that area. The surrounding brain tissue then dies – as it does in a stroke caused by a blocked artery.

Depending on the function of that part of the brain, this can cause problems with vision, speech, movement, or sensation. Like a subarachnoid hemorrhage, intracerebral hemorrhage can lead to life-threatening complications, especially if a lot of blood flows out.

Blood can also leak into the small gaps between the meninges (membranes covering the brain) or between the meninges and the skull:

• If veins in the brain are damaged, for example as a result of a fall, blood may leak into the space between two meninges known as the arachnoid mater and the dura mater. The medical term for this kind of bleeding is subdural hematoma.
• If an artery that supplies the meninges with blood is damaged, bleeding known as an epidural hematoma may occur. The blood then leaks into the space between the skull bone and the tough membrane covering the brain (the dura mater).

Like other types of bleeding in the brain, subdural and epidural hematomas can cause severe brain damage.