Herniation syndromes

Increased intra cranial pressure or masses causes shifting in the brain tissue through rigid opening in the skull (tentorial or foramen magnum) compressing other structures of the CNS causes herniation syndromes

  • Uncal herniation syndrome

The most common type, it is seen with lesions of the middle cranial fossa cases the uncus to herniate between the midbrain and the free edge of the tentorial hiatus into the posterior fossa

Clinical picture:

  • progressive impaired conscious level
  • ipsilateral dilation of the pupil
  • contralateral hemiparesis

It is seen in extradural, subdural and middle fossa tumors

2-central (Trans tentorial) herniation syndrome

Downward displacement of the diencephalon and midbrain through the tentorial hiatus

Clinical presentation

Diencephalic stage:

  • disturbed conscious level
  • yawns
  • bilateral small reactive pupil
  • impaired upward gaze and positive Dolls Eye sign
  • bilateral Babinski sign positive then Decorticate position

Midbrain upper pons stage

  • Chyne Stocke respiration
  • Midposition dilated fixed pupil
  • Lost Dolls Eye sign
  • Decerebrate position

Lower pons upper medulla stage

  • Shallow rapid respiration
  • Dilated fixed pupil
  • Flaccid lower limb with Babinski positive

Causes frontal parietal or occipital lobe tumors, bilateral subdural hematoma

3-Tonsillar herniation

The tonsils of the cerebellum is herniated through the foramen magnum into the upper spinal cord and lower medulla

Clinical presentation

  • hypertension,
  • high pulse pressure,
  • Chyne Stocke respiration,
  • and impaired conscious level,
  • with neck rigidity

It is caused by posterior fossa masses as tumors or blood and LP in patients with increased ICP

4- Subfalacin herniation (Cingulate)

General manifestations of increased ICP

  • Headache
  • Generalized , increase at night and recumbence more with focal causes
  • Vomiting projectile in nature more at morning not associated with nausea
  • Blurred vision and papilledema
  • Diplopia and squint due to Abducent nerve palsy

Investigations

  • CT Brain
  • MRI brain
  • ICP monitoring

Treatment

1-treatment of the cause

2-Measures lower ICP

  • Mannitol
  • Diuretics
  • Hyperventilation
  • Steroids
  • Barbiturate coma
  • Hypothermia
  • Ventricular drain