Herniation, ICP, Hydrocephalus Flashcards
Uncalled herniation
- compress CNIII - eye down and out, ptosis, ipsilateral dilated fixed pupil
- compress PCA - infarction of occipital lobe - contra lateral homonymous hemianopsia
- rupture paramedian artery - duret hemorrhages
- compress cerebral peduncles - contra lateral hemiparesis
Subfalcine herniation
Compress ACA: infarction
Cerebellar tonsillar herniation
Compress brainstem - respiratory arrest
Compression of diencephalon
Change in level of consciousness
What happens to the pupils in a diencephalon lesion?
Pupils are small, reactive due to loss of sympathetics
What happens to the pupils during a midbrain lesion?
Pupils are mid size, fixed due to loss of sympathetics and para sympathetics
Oculocephalic reflex
Head turns left, eyes move conjugately right = intact brainstem
Oculovestibular reflex
Cold water in ear canal - eyes go to side of stimulation = brainstem intact
Abducens nerve palsy
CNVI stretched during compression of brainstem causes Diplopoda, ipsilateral and contralateral paralysis of lateral gaze
Parinaud syndrome
- lesion in superior colliculi
- paralysis of upward gaze
- cause: hydrocephalus or pineal gland tumor
Decorticate vs. decerebrate?
Decorticate: leg extension, arm flexion - widespread lesion in cortex
Decerebrate: leg and arm extension - lesion disconnecting brainstem from cerebral hemispheres, usually in the upper midbrain
What does a blown pupil indicate?
Ipsilateral lesion of CNIII, uncal herniation, para sympathetics impaired
Communicating vs. non-communicating hydrocephalus?
Communicating: obstruction of flow in ventricle or foramina
Non-communicating: problem with reabsorption in subarachnoid space
