What happens during a brain hemorrhage?

Photo of a man holding his head in pain
PantherMedia / Alice Day

The skull protects the brain, but it also limits the amount of available space: Bleeding inside the skull quickly increases the pressure on the brain tissue. This often leads to serious complications.

A brain hemorrhage is bleeding in the brain that occurs when blood vessels inside the skull are damaged, for instance due to a major head injury. Other causes include problems with blood clotting and/or damage to the blood vessels in the brain – due to thickened and hardened artery walls (arteriosclerosis) or high blood pressure, for example. The bleeding is often caused by a ruptured (burst) brain aneurysm. A brain aneurysm is a bulge in an artery in or near the brain.

Why is a subarachnoid hemorrhage life-threatening?

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.

Illustration: Different types of bleeding in the brain

Different types of bleeding in the brain

What is intracerebral hemorrhage?

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.

Other types of bleeding

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.

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Steiner T, Juvela S, Unterberg A, Jung C, Forsting M, Rinkel G. European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage. Cerebrovasc Dis 2013; 35(2): 93-112.

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Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

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Created on November 29, 2018
Next planned update: 2021

Authors/Publishers:

Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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