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Brain herniation

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Illustrations

Brain
Brain
Brain hernia
Brain hernia

Alternative Names    Return to top

Herniation syndrome; Transtentorial herniation; Uncal herniation; Subfalcine herniation; Tonsillar herniation; Herniation - brain

Definition    Return to top

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    Return to top

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    Return to top

Exams and Tests    Return to top

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    Return to top

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:

Outlook (Prognosis)    Return to top

Once herniation in the brain's temporal lobe or the cerebellum occurs, death is often inevitable. Herniation of other areas of the brain areas has a more variable outlook.

Possible Complications    Return to top

When to Contact a Medical Professional    Return to top

If decreased alertness or other symptoms develop suddenly, particularly if there is a known head injury or brain lesion, go to the emergency room or call 911. A neurologist or neurosurgeon will ultimately be involved in the patient's care.

Prevention    Return to top

Prompt treatment of increased intracranial pressure and related disorders may reduce the risk of brain herniation.

Update Date: 7/14/2006

Updated by: J.A. Lee, M.D., Division of Surgery, UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network.

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