Space-Occupying Lesions : Brain Herniation

Question 1

Consequence of Raised Intracranial Pressure to Pathological Levels.

Answer 1

Brain Herniation - Normal Brain Structures are Forcefully Displaced.

Question 2

What is Coning?

Answer 2

Brainstem Compression : a grave sign indicating a neurosurgical emergency, requiring intervention

Question 3

Types of Brain Herniation (5).

Answer 3

1. Subfalcine.
2. Central.
3. Transtentorial/Uncal.
4. Tonsillar.
5. Transcalvarial.

Question 4

What is Subfalcine Brain Herniation?

Answer 4

Displacement of the Cingulate Gyrus under the Falx Cerebri.

Question 5

What is Central Brain Herniation?

Answer 5

Downward displacement of the brain.

Question 6

What is Transtentorial/Uncal Herniation?

Answer 6

Displacement of the Uncus of the Temporal Lobe under the Tentorium Cerebella.

Question 7

Clinical Features of Transtentorial/Uncal Herniation (2).

Answer 7

1. Ipsilateral Fixed, Dilated Pupil (CN III Palsy).

2. Contalateral Paralysis (Compression of Cerebral Peduncle).

Question 8

What is Tonsillar Herniation?

Answer 8

Displacement of the Cerebellar Tonsils through the Foramen Magnum - CONING.

Question 9

Clinical Features of Tonsillar Herniation.

Answer 9

1. Raised ICP : Compression of the Cardiorespiratory Centre.

2. Chiari I Malformation : No Raised ICP.

Question 10

What is Transcalvarial Herniation?

Answer 10

Displacement of the brain through a defect in the skull e.g. fracture, craniotomy site.