What is a brain bleed?

To most people, a “brain bleed” simply means any bleed inside your head. However, a doctor – and specifically doctors who treats brain bleeds (neurologists and neurosurgeons) – would say that a “brain bleed” (also known by the medical term intracranial hemorrhage) is too broad of a term. These doctors further describe brain bleeds by their exact location.

To better understand brain bleeds, it’s important to have a basic understanding of the different types. First, there are two main areas where bleeding can occur – bleeding can occur either within the skull but outside of the brain tissue, or inside the brain tissue. These areas are further divided as follows:

Bleeding within the skull but outside of the brain tissue

The brain has three membranes layers (called meninges) that lay between the bony skull and the actual brain tissue. The purpose of the meninges is to cover and protect the brain. Bleeding can occur anywhere between these three membranes. The three membranes are called the dura mater, arachnoid, and pia mater.

  • Epidural bleed (hemorrhage): This bleed happens between the skull bone and the utermost membrane layer, the dura mater.
  • Subdural bleed (hemorrhage): This bleed happens between the dura mater and the arachnoid membrane.
  • Subarachnoid bleed (hemorrhage): This bleed happens between the arachnoid membrane and the pia mater.

A view of the inner head showing the area -- the meninges -- between the skull and brain tissue. Brain bleeds can occur in the meninges layers, which are dura mater, arachnoid and subarachnoid space.

Brain bleeds can occur within the meninges, which is the area inside the skull but outside the actual brain tissue.

Bleeding inside the brain tissue

Two types of brain bleeds can occur inside the brain tissue itself – intracerebral hemorrhage (also called cerebral hemorrhage and hemorrhagic stroke) and intraventicular hemorrhage.

  • Intracerebral hemorrhage: This bleeding occurs in the lobes, pons and cerebellum of the brain (bleeding anywhere within the brain tissue itself including the brainstem).
  • Intraventricular hemorrhage: This bleeding occurs in the brain’s ventricles, which are specific areas of the brain (cavities) where cerebrospinal fluid is produced.

Epidural bleed, subdural bleed and subarachnoid bleed are brain bleeds outside of the actual brain tissue. Intraventricular hemorrhage and intracerebral hemorrhage are bleeds that occur inside the brain tissue.

Brain bleeds can occur in the meninges layers outside the brain tissue or inside the brain tissue itself.

What happens to the brain when there is bleeding inside the head?

Since the brain cannot store oxygen, it relies upon a series of blood vessels to supply oxygen and nutrients. When a brain hemorrhage occurs, oxygen may no longer be able to reach the brain tissue supplied by these leaky or burst vessels. Pooling of blood from an intracranial hemorrhage or cerebral hemorrhage also puts pressure on the brain and deprives it of oxygen.

When a hemorrhage interrupts blood flow around or inside the brain, depriving it of oxygen for more than three or four minutes, the brain cells die. The affected nerve cells and the related functions they control are damaged as well.

Are brain bleeds fatal?

Brain bleeds, regardless of location, usually happen suddenly. (However, some – for example, subdural hematomas – can take days to weeks before symptoms develop.) A brain bleed causes brain damage and yes, they can be life-threatening. The seriousness and outcome of a brain bleed depends on its cause, location inside the skull, size of the bleed, the amount of time that passes between the bleed and treatment, your age and overall health. Once brain cells die, they do not regenerate. Damage can be severe and result in physical, mental, and task-based disability.

Who is affected by brain bleeds (intracranial hemorrhage)?

Various types of intracranial hemorrhages strike people of all ages. Although cerebral hemorrhage (bleeding anywhere inside the brain tissue itself) and hemorrhagic stroke (specifically, when a blood vessel breaks and bleeds into the brain) are most commonly associated with older adults, they can also occur in children (pediatric stroke).

A few stats

  • Cerebral hemorrhage accounts for about 13% of all strokes in the United States. It is the second leading cause of stroke. (The leading cause of stroke is a blood clot – thrombus – in an artery in the brain, which blocks the flow of blood and cuts off needed oxygen and nutrients to the brain.)
  • Ruptured brain aneurysms affect about 30,000 people in the United States each year.
  • Arteriovenous malformations (AVM) are present in about 1% of the population, and about 2% of all hemorrhagic strokes are from an AVM each year.

What are the causes of brain bleeds (intracranial hemorrhage)?

Bleeding in the brain has a number of causes, including:

  • Head trauma, caused by a fall, car accident, sports accident or other type of blow to the head.
  • High blood pressure (hypertension), which can damage the blood vessel walls and cause the blood vessel to leak or burst.
  • Buildup of fatty deposits in the arteries (atherosclerosis).
  • Blood clot that formed in the brain or traveled to the brain from another part of the body, which damaged the artery and caused it to leak.
  • Ruptured cerebral aneurysm (a weak spot in a blood vessel wall that balloons out and bursts).
  • Buildup of amyloid protein within the artery walls of the brain (cerebral amyloid angiopathy).
  • A leak from abnormally formed connections between arteries and veins (arteriovenous malformation).
  • Bleeding disorders or treatment with anticoagulant therapy (blood thinners).
  • Brain tumor that presses on brain tissue causing bleeding.
  • Smoking, heavy alcohol use, or use of illegal drugs such as cocaine.
  • Conditions related to pregnancy or childbirth, including eclampsia, postpartum vasculopathy, or neonatal intraventricular hemorrhage.
  • Conditions related to abnormal collagen formation in the blood vessel walls that can cause to walls to be weak, resulting in a rupture of the vessel wall.

What are the symptoms of brain bleeds (intracranial hemorrhage)?

Symptoms of a brain hemorrhage depend on the area of the brain involved. In general, symptoms of brain bleeds can include:

  • Sudden tingling, weakness, numbness, or paralysis of the face, arm or leg, particularly on one side of the body.
  • Headache. (Sudden, severe “thunderclap” headache occurs with subarachnoid hemorrhage.)
  • Nausea and vomiting.
  • Confusion.
  • Dizziness.
  • Seizures.
  • Difficulty swallowing.
  • Loss of vision or difficulty seeing.
  • Loss of balance or coordination.
  • Stiff neck and sensitivity to light.
  • Abnormal or slurred speech.
  • Difficulty reading, writing or understanding speech.
  • Change in level of consciousness or alertness, lack of energy, sleepiness or coma.
  • Trouble breathing and abnormal heart rate (if bleed is located in brainstem).

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