Brain herniation: Difference between revisions

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'''Brain herniation''' is a potentially fatal condition that occurs when parts of the brain are displaced from their usual position due to increased intracranial pressure. This displacement can compress brain structures and blood vessels, leading to decreased blood flow, oxygen deprivation, and further increase in intracranial pressure, creating a vicious cycle. Brain herniation can result from various causes, including traumatic brain injury, stroke, tumors, and infections.
== Brain Herniation ==


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==Types==
'''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.
There are several types of brain herniation, each with distinct characteristics and implications for treatment and prognosis:


* [[Uncal herniation]]: This occurs when the uncus of the temporal lobe shifts downward, potentially compressing the brainstem and the third cranial nerve.
== Types of Brain Herniation ==
* [[Central herniation]]: In this type, the diencephalon and parts of the temporal lobes shift downward through the tentorial notch.
* [[Cingulate herniation]]: This involves the displacement of the cingulate gyrus under the falx cerebri.
* [[Transcalvarial herniation]]: Brain tissue herniates through a defect in the skull, often due to surgery or trauma.
* [[Tonsillar herniation]]: Also known as cerebellar or foramen magnum herniation, this occurs when the cerebellar tonsils move downward through the foramen magnum, potentially compressing the brainstem and leading to death.


==Symptoms==
Brain herniation can be classified into several types based on the location and direction of the herniation:
Symptoms of brain herniation can vary depending on the type but may include:


* Changes in consciousness, ranging from drowsiness to coma
=== Subfalcine Herniation ===
* Pupil dilation, particularly on one side, if the third cranial nerve is affected
[[File:Subfalcine-herniation-001.jpg|Subfalcine herniation|thumb|left]]
* Changes in breathing patterns
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.
* Weakness or paralysis on one side of the body
 
=== 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
* Headache
* Seizures
* Vomiting
* Pupillary changes
* Abnormal posturing, such as [[File:Decorticate.PNG|Decorticate posturing|thumb|right]]
 
== Diagnosis ==
 
[[File:Brain_injury_with_herniation_MRI.jpg|Brain injury with herniation on MRI|thumb|left]]
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.


==Diagnosis==
[[File:Brain_herniation_MRI.jpg|MRI showing brain herniation|thumb|right]]
Diagnosis of brain herniation involves clinical assessment and imaging studies. Computed tomography (CT) scans and magnetic resonance imaging (MRI) are crucial for identifying the type and extent of herniation.


==Treatment==
== Treatment ==
Treatment of brain herniation is a medical emergency and focuses on reducing intracranial pressure, treating the underlying cause, and supporting vital functions. Interventions may include:


* Medications to reduce brain swelling, such as mannitol or hypertonic saline
Treatment of brain herniation focuses on reducing intracranial pressure and addressing the underlying cause. This may include:
* Ventriculostomy to drain cerebrospinal fluid and relieve pressure
* Surgical decompression to remove the source of increased pressure or to create more space for the swollen brain


==Prognosis==
* Surgical intervention to remove mass lesions or relieve pressure
The prognosis for brain herniation depends on the speed of diagnosis and treatment, the underlying cause, and the extent of brain damage. Early intervention can improve outcomes, but the condition can be fatal without prompt treatment.
* Administration of [[osmotic diuretics]] such as [[mannitol]]
* Hyperventilation to reduce carbon dioxide levels and decrease intracranial pressure
* Corticosteroids to reduce inflammation


==Prevention==
== Prognosis ==
Preventing brain herniation involves managing conditions that can lead to increased intracranial pressure, such as head injuries, strokes, and brain tumors, with appropriate medical and surgical interventions.
 
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.
 
== Related Pages ==
 
* [[Intracranial pressure]]
* [[Cerebral edema]]
* [[Traumatic brain injury]]


[[Category:Neurology]]
[[Category:Neurology]]
[[Category:Neurosurgery]]
[[Category:Neurosurgery]]
[[Category:Medical emergencies]]
{{Medicine-stub}}
<gallery>
File:Decorticate.PNG|Decorticate posturing
File:Brain_herniation_types-2.svg|Types of brain herniation
File:Subfalcine-herniation-001.jpg|Subfalcine herniation
File:Brain_injury_with_herniation_MRI.jpg|Brain injury with herniation on MRI
</gallery>
== Brain_herniation ==
<gallery>
File:Brain_herniation_MRI.jpg|MRI showing brain herniation
File:Decorticate.PNG|Decorticate posturing
File:Brain_herniation_types-2.svg|Types of brain herniation
File:Subfalcine-herniation-001.jpg|Subfalcine herniation
File:Brain_injury_with_herniation_MRI.jpg|MRI of brain injury with herniation
</gallery>

Revision as of 11:17, 23 March 2025

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
    Decorticate posturing

Diagnosis

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.

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.

Related Pages