Acute Neuro conditions with ocular signs

Question 1

what is painful 3rd nerve palsy also know as?

Answer 1

oculomotor nerve palsy

Question 2

what does the oculomotor nerve innervate?

Answer 2

levator palpebrae superior (upper eyelid)
sphincter papillae (pupil dilation and constriction)
ocular muscles other than sup orbital and lateral rectus

Question 3

How common is painful 3rd nerve palsy?

Answer 3

rare

Question 4

what are the causes of 3rd nerve palsy?

Answer 4

congenital- present at birth
acquired- head trauma, brain tumour, migraine, aneurysm, DM, high bp, infection

pressure/compression of nerve
inadequate blood flow to nerve

Question 5

what are the risk factors for 3rd nerve palsy?

Answer 5

alcohol

diet and lifestyle, cholesterol levels (think DM and high bp risk factor)

Question 6

what is the presentation of 3rd nerve palsy (complete or partial) ?

Answer 6

ptosis
diplopia
enlarged pupil

Question 7

what is the difference between a complete and partial 3rd nerve palsy?

Answer 7

complete 3rd nerve palsy - eye cant move in and up (goes out and down),
complete closure of eyelid
enlarged pupil which doesnt not respond normally to light

partial- affects functions of 3rd nerve to varying degrees
may/may not have pupil involvement

Question 8

what are the first signs of 3rd nerve palsy?

Answer 8

ptosis or enlarged pupil

Question 9

if there is pupil sparring what are the likely causes of the 3rd nerve palsy?

Answer 9

diabetes and htn - because most pupil sparring cases are micrvascular in origin

Question 10

if a pt presented with:
sudden onset 3rd n palsy with pupil involvement
no hx of head trauma

what is your ddx until proven otherwise?

Answer 10

intracranial anuerysm

life threatening emergency as can lead to SAH!!!

Question 11

what investigations would you run for a 3rd nerve palsy presentation?

Answer 11

Optic nerve examination:

• visual acuity
• visual fields
• colour vision
• pupil - appearance, direct and consensual reflex and accomodation
• RAPD (relative afferent pupillary defect)
• MRI/CT

Question 12

what is the RAPD testing for?

Answer 12

unilateral or asymmetrical optic nerve disease

Question 13

if you did an RAPD and one eye was abnormal what would you expect?

Answer 13

When you shine a light in the good eye, both pupils constrict.
Shift light and shine in bad eye and both pupils will dilate.
This dilation response is in both eyes, despite only one eye being affected. This is the essence of the RAPD.

Question 14

what is an argyll robertson pupil?

Answer 14

pupils which constrict on accommodation but not to light

Question 15

what is an adie pupil/holme-adie’s syndrome?

Answer 15

tonically dilated pupils which constrict quicker to accomodation than to light. (i.e.light near dissociation)
(NB: still responds to light but just at slower rate)

Question 16

how would you treat 3rd nerve palsy?

Answer 16

have to leave for the body to heal - if palsy still present after 6 months then eye muscle surgery can be done

if tumour or aneurysm need surgery to relieve pressure

if diplopia present pathc eye or give prism specs to relieve diplopia

surgery can be done to correct ptosis

Question 17

what i the differnence between binocular diplopia and monocular diplopia?

Answer 17

binocular diplopia = double visiononly eviden when looking through both eyes and disappears if one eye covered. caused by misalignment of eyes

monocular diplopia = double vision in one eye - persists depsite covering any of the eyes. structural problem ussually the cause

Question 18

What is horner’s syndrome?

Answer 18

results from interruption of sympathetic nerve supply to eye
characterized by: 
partial ptosis (lower lid may also be a bit higher - upside down ptosis) 
anyhdrosis (loss of sweating on that side)
and miosis (delay of dilation in the dark) 

in congenital horners or long standing horners you may seee iris heterochromia (affected eye has hypopigmentation)

Question 19

what are the causes of horners syndrome?

Answer 19

lesion of primary neuron/postganglionic neuron/preganglonic neuron

brain tumour, pancoast tumour
brainstem stroke
migraine

trauma to brachial plexus

dissecting CA aneurysm
CA ischemia

can be congenital, acquired or hereditary

Question 20

pt presents with acute onset of horners - whats your ddx?

Answer 20

carotid artery dissection

Question 21

pt presents with horners and pain in axilla, arm, shoulder, hand- whats the likely cause?

Answer 21

pancoast tumour

Question 22

what investigations would you run for horners syndrome?

Answer 22

CXR - pancoast tumour 
CT- stroke suspicion
MRI and MRA of brain and neck to exclude CA dissection in painful horners 
topical apraclodine test 
topical hydroxyamphetamine test

Question 23

what results would you expect from an apraclondine test in horners?

Answer 23

pupil will dilate (mydriatic action of abnormal pupil)

Question 24

what results would you expect from a hydroxyamohetamine test in horners?

Answer 24

dilation will not occur if its a postganglionic (3rd order neurone) lesion
distinguished from 1st and 2nd order neuron lesions

Question 25

what treatment is available for horners?

Answer 25

neurosurgery for aneurysm related horners
vascular surgical care for CA dissection / aneursym
treat underlying cause!