What is Transtentorial herniation?
A transtentorial herniation is the movement of brain tissue from one intracranial compartment to another. This includes uncal, central, and upward herniation. These are life-threatening and time-critical pathologies that may be reversible with emergent surgical intervention and medical management.
When does Transtentorial herniation occur?
Upward transtentorial herniation can occur when an infratentorial mass (eg, tumor in the posterior fossa, cerebellar hemorrhage) compresses the brain stem, kinking it and causing patchy brain stem ischemia. The posterior 3rd ventricle becomes compressed.
Which nerve is compromised in Transtentorial herniation?
Uncal (Transtentorial) Herniation. The uncus is the most medial part of the temporal lobe. When it is squeezed against the tentorium, it exerts pressure on the third cranial (oculomotor) nerve as it leaves the midbrain and travels along the free edge of the tentorium.
Is Transtentorial herniation the same as uncal herniation?
Uncal herniation is a subtype of descending transtentorial herniation that involves the uncus, caused by increased intracranial pressure. The most common causes of uncal herniation include brain lesions or expanding mass lesions.
What causes Transtentorial herniation?
What are the different types of herniation?
Brain herniation is classified as follows:
- Subfalcine herniation.
- Transalar (transsphenoidal) herniation.
- Transtentorial uncal herniation.
- Central (trans-tentorial) herniation (descending and ascending)
- Cerebellar tonsillar herniation.
- Transcalvarial herniation.
What are signs of herniation?
Symptoms
- High blood pressure.
- Irregular or slow pulse.
- Severe headache.
- Weakness.
- Cardiac arrest (no pulse)
- Loss of consciousness, coma.
- Loss of all brainstem reflexes (blinking, gagging, and pupils reacting to light)
- Respiratory arrest (no breathing)
What is Cushings reflex?
The Cushing reflex (vasopressor response, Cushing reaction, Cushing effect, and Cushing phenomenon) is a physiological nervous system response to acute elevations of intracranial pressure (ICP), resulting in Cushing’s triad of widened pulse pressure (increasing systolic, decreasing diastolic), bradycardia, and …
How does uncal herniation produce ipsilateral hemiparesis?
The cardinal signs of uncal herniation are an acute loss of consciousness associated with ipsilateral pupillary dilation and contralateral hemiparesis. These symptoms are due to compression or displacement of ascending arousal pathways, the oculomotor nerve (CN III), and the corticospinal tract.
Which of the following are signs of brainstem herniation?
Signs and symptoms may include:
- High blood pressure.
- Irregular or slow pulse.
- Severe headache.
- Weakness.
- Cardiac arrest (no pulse)
- Loss of consciousness, coma.
- Loss of all brainstem reflexes (blinking, gagging, and pupils reacting to light)
- Respiratory arrest (no breathing)