Brain herniation

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
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Brain herniation
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Headache, vomiting, altered mental status, coma
Complications	Brain damage, death
Onset	Sudden
Duration	Variable
Types	Subfalcine herniation, transtentorial herniation, tonsillar herniation
Causes	Traumatic brain injury, stroke, brain tumor, abscess
Risks	Increased intracranial pressure
Diagnosis	CT scan, MRI
Differential diagnosis	Intracerebral hemorrhage, cerebral edema
Prevention	N/A
Treatment	Surgery, osmotic therapy, hyperventilation
Medication	N/A
Prognosis	Poor if untreated
Frequency	Common in severe head injury
Deaths	N/A

Brain Herniation

Types of brain herniation

Brain herniation occurs when there is a displacement of brain tissue due to increased intracranial pressure. This condition is a medical emergency and can lead to severe neurological damage or death if not treated promptly.

Types of Brain Herniation

Brain herniation can be classified into several types based on the location and direction of the herniation:

Subfalcine Herniation

Subfalcine herniation

Subfalcine herniation, also known as cingulate herniation, occurs when the cingulate gyrus is displaced under the falx cerebri. This is the most common type of herniation and can compress the anterior cerebral artery, leading to ischemia.

Transtentorial Herniation

Transtentorial herniation can be further divided into uncal and central herniation:

• Uncal Herniation: This occurs when the uncus of the temporal lobe is pushed downward through the tentorial notch. It can compress the oculomotor nerve, leading to a dilated pupil on the affected side, and can also compress the brainstem.
• Central Herniation: This involves downward displacement of the brainstem and diencephalon through the tentorial notch, potentially leading to decerebrate posturing and coma.

Tonsillar Herniation

Tonsillar herniation occurs when the cerebellar tonsils are pushed downward through the foramen magnum. This can compress the medulla oblongata, affecting vital functions such as respiration and cardiac function.

External Herniation

External herniation occurs when brain tissue is displaced through a defect in the skull, often due to trauma or surgery.

Clinical Presentation

The symptoms of brain herniation depend on the type and severity of the herniation. Common signs include:

• Altered level of consciousness
• Headache
• Vomiting
• Pupillary changes
• Abnormal posturing, such as

  File:Decorticate.PNG

  Decorticate posturing

Diagnosis

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Brain injury with herniation on MRI

Diagnosis of brain herniation is typically made using imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI). These imaging modalities can reveal the displacement of brain structures and the presence of any mass lesions or edema.

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MRI showing brain herniation

Treatment

Treatment of brain herniation focuses on reducing intracranial pressure and addressing the underlying cause. This may include:

• Surgical intervention to remove mass lesions or relieve pressure
• Administration of osmotic diuretics such as mannitol
• Hyperventilation to reduce carbon dioxide levels and decrease intracranial pressure
• Corticosteroids to reduce inflammation

Prognosis

The prognosis for brain herniation varies depending on the cause, severity, and timeliness of treatment. Early intervention can improve outcomes, but severe herniation can result in permanent neurological deficits or death.

See also

• Intracranial pressure
• Cerebral edema
• Traumatic brain injury