supranucelar shit

Question 1

what is skew deviation

Answer 1

think of diagnosis if their is a newly acquired vertical diplpina

usually associated with horizontal and vertical deviation

it = concomitant hypertropia in pt with posterior fossa disease (eye = up)

due to brainstem or cerebellar lesion

Question 2

r skew deviation would produce

Answer 2

right hypertropia

and incylotorison

if torsion = towards the hypertrophic eye = skew

Question 3

differentiating between skew and a 4th

Answer 3

skew - higher eye is intorted

in superior oblique higher eye is extorted

in 4th nerve their is ipsilateral eyxclytorsion

Question 4

upright supine test

Answer 4

in a 4th nerve palsy when pt is lying down vs sitting up their isn’t much difference in thyopermetropia in skew hypermetropia singifcantkly decreases (if it decreases indicates otolith dysfunction which is associated with skew)

Question 5

ateiology of a skew deviation

Answer 5

posterior fossa lesion

in Arnold chiari malformation

trauma

abscess

haemorrhage

Question 6

management for skew

Answer 6

usually transient , treat conservatively for 6 months afterwards

Question 7

5 step test for skew

Answer 7

pct in primary postion

pct in side gaze

pct on tilt

upright supine

pct on maddox rod

Question 8

difference between a 4th and skew deviation

Answer 8

incyclotrosion of higher eye in skew in 4th nerve eyxlotrsion excyclotrosion of higher eye

other neuro signs

usually are present e.g. gaze evoked nystagmus

skew typically associated with other neuro signs such as gaze evoked nystagmus and gaze palsies

Question 9

what is an internuclear opthalmolplegia

Answer 9

defective adduction in ipsilateral side of lesion

own shows reduced adduction saccades

VOR

OKN

ALSO can be affected

dissociated nystagmus of contrlateral eye

contralateral abducting nystagmus

saccades typically slow and hypsometric

Question 10

convergence and INO association

Answer 10

posterior INO = convergence is intact

Anterior INO= convergence is reduced

Question 11

ateiology of INO

Answer 11

deymyleination in younger patents

brain ishchameia in older patients

Arnold chiari malformato meningitis

Question 12

bilateral INO

Answer 12

in primary position eyes are usually straight

e.g. if looking to the right, right eye might have a weak adduction and when you look to the left their Weill be a dissociated horizontal abducting nystagmus

due to lesion for 6th nerve nucleus has to talk to contralateral 3rd nerve nucleus

structure = medial longitudinal fasiculus

adduction weakness

abducting nystagmus in both eyes

asymmetric

no associated skew deviation

Question 13

management of INO

Answer 13

resolution documented in 50% of pts

medication (same for nystagmus)- gabapentin , baclofen , memantine

MRI

Question 14

differential diagnosis for INO

Answer 14

Myasthenia Gravis

but convergence is often affected in MG

Question 15

what causes an ino

Answer 15

lesion at the site of the medial longnituddinal fasiculus

Question 16

when to think of an ino diagnosis

Answer 16

ino with or without exotropia if their is an adduction problem only , no ptosis no up and down gaze plays, no up and down movement to suggest third nerve palsy

++++ especially if pp = straight

in a young person you should be thinking of demyelinating disease

in older could be stroke and pseudo ino - most commonly caused my Myasthenia Gravis

Question 17

quick ino features

Answer 17

adduction defects

dissociated horizontal abducting nystagmus

if in. with directions = bilateral

if exotropic = EBINO

MRI of mlf to ensure not stroke or demyelinating disease at the level of the medial longntiudinal fasiculus

Question 18

1 and a half syndrome is….

Answer 18

a condition where one eye is completely paralysed for horizontal movements and the other can only move outwards

contralateral exo and ipsilateral gaze palsy

e..g left 1 and a half syndrome

left eye will be unable to adbuct and adduct and right eye will be unable to adduct but will be able to abduct

e..

Question 19

ateiology of one and a half syndrome

Answer 19

ms

pontine lesion

brain stem infarction

arteriovenous malformation

myasthenia gravis the mimic

Question 20

lesion in the 6th nerve palsy produces a

Answer 20

horizontal gaze palsy

Question 21

ateiology of parinauds

Answer 21

pineal gland tumour

vascular accident in the dorsal midbrain

lsesion in the Sylvia aqueduct

obstructive hydrocephalus

Question 22

signs of parinauds

Answer 22

light near dissociation

pupils react to near but not to light

on attempted upgazelid retraction. and convergence retraction nystagmus

dorsal midbrain syndrome = so loss oof upgaze

lid retraction of down gaze colliers sign

convergence weakness/spasm

sun setting sign if associated with hydrocephalus

Question 23

progressive suprnuclear palsy

Answer 23

defective vetrtical saccades up gaze and downgaze

progressivve loss of visual movement

smooth pursuit and VOR

symptoms due to poor muscle tone and posture - difficulty swallowing

ateiology = extreme brainstem degernation of reticular formation

ocuclocrgyric crisis -

looss of balance presents in 6th decade

bells phenomena affected = eye dosnt close and is seen going up
]]may have complete opthalmoloplegia

signficicant decline appears year after year

Question 24

differentials for parkisonsn

Answer 24

defective upwards and slow vertical saccades

Huntingtons dorea

should be differentiated from other basal ganglia diseases

Question 25

double elevator palsy

Answer 25

one eye cannot look up

nad in pp /// hypotropia of affected eye

ateiology = supranuclear lesion in dorsal midbrain

differentials = browns -limitation of upgaze in adduction

duanes - globe reraction in downgaze

usually congenital

usually unilateral

pseudo ptosis

Question 26

gaze palsies

Answer 26

vertical gaze palsy - due to lesions in the posterior commissure

rostral intestinal nucleus of the NFL

bells phenomena = vertical dolls head should be intact

lesion in the basal ganglia - Parkinson’s disease

unilateral lesion

oculocygruc crisis = eyes roll into the back of the head

lesion at the dorsal midbrain

Question 27

horziontal gaze palsy

Answer 27

fibres descend from the FEF though basal ganglia and then deccuate before going to the PPRF

lesion before decussation

loss of conjugate gaze to contractural side

lesion below decussation - loss of conjugate movement to ipsilateral side

Question 28

oculomotor apraxia

Answer 28

reduced induced horizontal saccades

selective horizontal plasy

absent voluntary horizontal gazer

vertical gaze nroammly

benign

bilateral FEF lesions

corpus callosium lesion