Brain herniation
Key points
- A brain herniation is the displacement of brain tissue, cerebrospinal fluid, and blood vessels outside the compartments in the head that they normally occupy.
- A brain herniation occurs when pressure inside the skull (intracranial pressure) increases and displaces brain tissues.
- A neurologic examination would show an impaired level of consciousness.
- The goal of treatment is to save the patient's life.
Alternative names
Herniation syndrome; Transtentorial herniation; Uncal herniation; Subfalcine herniation; Tonsillar herniation; Herniation - brain
Definition
A brain herniation is the displacement of brain tissue, cerebrospinal fluid, and blood vessels outside the compartments in the head that they normally occupy. A herniation can occur through a natural opening at the base of the skull (called the foramen occipitalis) or through surgical openings created by a craniotomy procedure.
Herniation can also occur between compartments inside the skull, such as those separated by a rigid membrane called the "tentorium".
Causes, incidence, and risk factors
A brain herniation occurs when pressure inside the skull (intracranial pressure) increases and displaces brain tissues. This is commonly the result of brain swelling from a head injury. It can also be caused by space-occupying lesions such as primary brain tumor, metastatic brain tumor, and hemorrhages or strokes that produce swelling within the brain. Hydrocephalus (accumulation of fluid in the brain) can also lead to brain herniation.
A brain herniation itself often causes massive stroke. This results from poor blood supply to some areas of the brain and compression of vital structures that regulate your breathing and circulation. This can rapidly lead to death or brain death.
Brain herniations are the most common secondary effect of expanding masses in the brain.
Symptoms
- Progressive loss of consciousness
- Coma
- Irregular breathing
- Respiratory arrest (no breathing)
- Irregular pulse
- Cardiac arrest (no pulse)
- Loss of all brainstem reflexes (blink, gag, pupillary reaction to light)
Signs and tests
A neurologic examination would show an impaired level of consciousness. Depending on the severity of the herniation, one or several brainstem reflexes and cranial nerve functions will be impaired. The patient would show an inability to breathe consistently, and heart rhythms would be irregular.
Treatment
Brain herniation is a medical emergency! The goal of treatment is to save the patient's life.
To help reverse or prevent a brain herniation, the medical team will treat increased swelling and pressure in the brain. This can be accomplished by:
Frequently asked questions
What is brain herniation?
A brain herniation is the displacement of brain tissue, cerebrospinal fluid, and blood vessels outside the compartments in the head that they normally occupy. A herniation can occur through a natural opening at the base of the skull (called the foramen occipitalis) or through surgical openings created by a craniotomy procedure. Herniation can also occur between compartments inside the skull, such as those separated by a rigid membrane called the "tentorium".
What are the risk factors for brain herniation?
A brain herniation occurs when pressure inside the skull (intracranial pressure) increases and displaces brain tissues. This is commonly the result of brain swelling from a head injury. It can also be caused by space-occupying lesions such as primary brain tumor, metastatic brain tumor, and hemorrhages or strokes that produce swelling within the brain. Hydrocephalus (accumulation of fluid in the brain) can also lead to brain herniation. A brain herniation itself often causes massive stroke. This results from poor blood supply to some areas of the brain and compression of vital structures that regulate your breathing and circulation. This can rapidly lead to death or brain death.
What are the symptoms of brain herniation?
- Progressive loss of consciousness
- Coma
- Irregular breathing
- Respiratory arrest (no breathing)
- Irregular pulse
- Cardiac arrest (no pulse)
- Loss of all brainstem reflexes (blink, gag, pupillary reaction to light)
Written and revised by
Andrey Nailor, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.