Brain herniation

Cerebral Herniation Syndromes

- Cingulate Herniation

 If one hemisphere is forced under the falx, the cingulate lobe is the first portion of that hemisphere to be displaced

 confused and drowsy

 The anterior cerebral artery territory infarct leading to contralateral lower extremity weakness and urinary incontinence

 

- Uncal Herniation

  The most common clinically significant traumatic herniation syndrome

  a form of transtentorial herniation

  the third cranial nerve is compressed; anisocoria, ptosis, impaired extraocular movements, and a sluggish pupillary light reflex develop on the side ipsilateral to the expanding mass lesion

 Kernohan's notch:  hemiparesis on the same side of the body as the offending mass

 Duret hemorrhages 

 

- Central Transtentorial Herniation

  The initial clinical manifestation may be a subtle change in mental status or decreased LOC, bilateral motor weakness, and pinpoint pupils (2 mm). Light reflexes are still present but are often difficult to detect. Muscle tone is increased bilaterally, and bilateral Babinski's signs may be present.

  Respiratory patterns initially include yawns and sighs and progress to sustained tachypnea, followed by shallow slow, and irregular breaths immediately before respiratory arrest

 

- Cerebellotonsillar Herniation

  cerebellar tonsils herniate downward through the foramen magnum

  Clinically, patients demonstrate sudden respiratory and cardiovascular collapse as the medulla is compressed. Pinpoint pupils are noted. Flaccid quadriplegia is the most common motor presentation because of bilateral compression of the corticospinal tracts. 

 

 

- Upward Transtentorial Herniation

 occurs as a result of an expanding posterior fossa lesion. The LOC declines rapidly. These patients may have pinpoint pupils from compression of the pons. The downward conjugate gaze is accompanied by the absence of vertical eye movements.