Acute visual disturbance 3 - ocular motor palsies

Question 1

muscle that moves the eye laterally

Answer 1

lateral rectus muscle

Question 2

muscle that moves the eye medially

Answer 2

medial rectus muscle

Question 3

muscle that moves the eye inferiorly

Answer 3

inferior rectus muscle

Question 4

muscle that moves the eye superiorly

Answer 4

superior rectus muscle

Question 5

what are the two oblique muscles called

Answer 5

superior oblique muscle
inferior oblique muscle

Question 6

levator palpebrae superioris muscle

Answer 6

supplied by third cranial nerve
in a third nerve palsy, you get a ptosis because of this muscle

Question 7

Hx of cranial nerve palsies

Answer 7

diplopia
anisocoria
ptosis
ophthalmoplegia
nystagmus
pain
systemic (headache, tinnitus, polyneuropathies)
variable vision (difficulty focussing)

Question 8

acute onset is more likely to be stuff like

Answer 8

vascular, GCA, trauma, infection

Question 9

subacute onset (weeks) is more likely to be stuff like

Answer 9

demyelination eg. MS

Question 10

gradual onset (months to years) is more likely to be stuff like

Answer 10

compressive eg. slowly growing tumour

Question 11

characterise the diplopia

Answer 11

horizontal, vertical, diagonal, torsional

Question 12

vertical diplopia on downward gaze

Answer 12

4th nerve palsy

Question 13

important things on PMHx

Answer 13

DM, HTN, lipids, thyroid, myasthenia gravis

Question 14

element of ophthalmic examination

Answer 14

visual acuity
visual fields
pupil reflexes
opthalmoscopy
colour vision

Question 15

testing eye movements

Answer 15

start off with distance target

Question 16

acronym for remembering the elements of the ophthalmic exam

Answer 16

AFROC

Question 17

third nerve palsy looks like

Answer 17

occulumotor nerve
down and out with ptosis
most common is vasculopathic/aneurysm

Question 18

fourth nerve palsy looks like

Answer 18

trochlear nerve
nasal upshoot on contralateral gaze

Question 19

sixth nerve palsy looks like

Answer 19

unopposed medial nerve action
abducens nerve

Question 20

sixth nerve palsy looks like

Answer 20

Question 21

Sixth nerve palsy is when

Answer 21

the eye is turned inward because it affects the lateral rectus muscle so the eye can’t turn fully outward.

Question 22

abducens nerve palsy is

Answer 22

sixth nerve palsy

Question 23

aetiology of abducens nerve palsy

Answer 23

microvascular, trauma, raised ICP, idiopathic, GCA

Question 24

presentation of abducens nerve palsy

Answer 24

horizontal diplopia worse when looking at a distance and on ipsilateral gaze
esotropia also worse on distance and ipsilateral gaze
most common palsy

Question 25

Ddx of abducens nerve palsy

Answer 25

thyroid eye disease, orbital tumour, Duane syndrome

Question 26

management of abducens nerve palsy

Answer 26

MRI brain and orbits: patients <50years, polyneuropathy or systemic symptoms, history of cancer, no microvascular risk factors FBC, BSL, ESR, CRP, lipids on older patients; other blood as indicated manage vascular risk factors driving advice, short term patching, prism lenses, botox injection or strabismus surgery

Question 27

prognosis of abducens nerve palsy

Answer 27

70% of microvascular cases recover in 6-12 weeks

Question 28

forth nerve palsy is more obvious on

Answer 28

ipsilateral head tilt

Question 29

a trochlear nerve palsy is

Answer 29

fourth nerve palsy

Question 30

aetiology of forth nerve palsy

Answer 30

microvascular, congenital, trauma, idiopathic

Question 31

presentation of forth nerve palsy

Answer 31

vertical diplopia and compensatory contralateral head tilt diplopia worse on downsize and contralateral gaze nasal upshoot (hypertropia on adduction) and ipsilateral head tilt recent head trauma

Question 32

Ddx of trochlear/4th nerve palsy

Answer 32

myasthenia graves, thyroid eye disease, third nerve palsy

Question 33

management of trochlear/4th nerve palsy

Answer 33

CT or MRI: dorsal midbrain lesion/contusion/infarction control of vascular risk factors in older patients driving advice, short term patching, longer term prisms +/- surgery

Question 34

third nerve palsy is when the eye goes

Answer 34

down and out

Question 35

a blown pupil in third nerve palsy is suspicious for

Answer 35

aneurysm

Question 36

why is blown pupil indicative of an aneurysm in third nerve palsy

Answer 36

parasympathetic fibres travel on the outside of the third nerve so when the third nerve travels near the posterior communicating artery, the outermost fibres (parasympathetic supply) are the first to be affected which causes the pupils to not be able to constrict (hence they get blown)

Question 37

oculomotor nerve palsy aetiology

Answer 37

microvascular, aneurysm, tumour, trauma, infiltrative, (e.g. leukaemia) most cases without pupil involvement are ischaemic (HTN, DM etc)

Question 38

presentation of oculomotor nerve palsy

Answer 38

diplopia, ptosis, +/- pain, +/- pupil involvement (light and accomodation) eye turned 'down and out' unable to adduct/infraduct/supraduct

Question 39

Ddx of oculomotor nerve palsy

Answer 39

myasthenia gravis, thyroid orbitopathy, GCA

Question 40

management of oculomotor nerve palsy

Answer 40

acute 3rd nerve palsy with fixed dilated pupil = emergency CTA or MRI/A FBC, ESR, CRP for ?inflammatory causes (including GCA) you may not need to image if there is no pupil involvement but you ned to see the patient everyday to ensure there is no new pupil involvement medical management of vascular risk factors driving advice, short term patching, longer term prism lenses +/- surgery

Question 41

prognosis of occulomotor nerve palsy

Answer 41

ischameic cases often resolve within 3 months

Question 42

diplopia and driving

Answer 42

people with diplopia are generally considered not fit to drive for diplopia with an occluder, a three month non-driving period applies in order to reestalbish depth perception

Question 43

sudden loss of unilateral vision and driving

Answer 43

person shouldn't be driving for an appropriate period (usually there months) to adapt to their new visual circumstance and re-etablish depth perception

Question 44

summary of eye muscles and their actions

Answer 44