Neuro-ophthalmology Flashcards Preview

Ophthalmology > Neuro-ophthalmology > Flashcards

Flashcards in Neuro-ophthalmology Deck (36):
1

What 3 things should one comment on when describeing an optic disk?

The three C's:

The colour

The contour

The cup-disk ratio

2

What are the sings of optic disk swelling

The colour: pink

The contour: Blurred with haemorrhages at the contour

The cup-disk ratio: not enlarged but hard to see anyway

3

What are some DDx's of optic disk swelling

optic neuritis

papilloedema (has to be bilateral)

malignant hypertension

arteritic anterior ischaemic optic neuropathy (aion)

non-arteritic aion

4

What is seen on fundoscopy in pt's with optic neuritis?

a swollen disc with a blurred margin

If the inflammation of the optic nerve is further back then the optic disc may not be swollen (retrobulbar neuritis)

with a pink colour and normal cup

5

What symptoms will a patient with optic neuritis complain of (and what is the typical age demographic)?

Complain of:
1) Blurred vision
2) Dull ache esp. on eye movement

(normally young to middle aged)

6

What examinations are indicated in optic neuritis and what would the findings be?

Fundoscopy findings (blurred disk margin showing swollen disk or not) and

Visual fields --> reduced centrally due to para-central scotoma or enlarged blind spot.

Swinging flashlight test --> RAPD

7

What investigations should be done in recurrent optic neuritis?

MRI to check for MS

8

What does papilloedema mean?

swelling of the optic discs

due to increased intracranial pressure

(therefore must be bilateral)

9

When is the only occasion that papilloedema can be unilateral?

If the patient has developed optic atrophy in one eye previously

10

What will a patient with papilloedema complain of?

transient blurring of vision

headaches

11

What are the early signs of papilloedema?

Fundoscopy:

1) haemorrhages at disk margin

2) exudates (lipid break-down products that are left behind after localized edema resolves, they are around the macula)

3) cotton wool spots (debris from dead nerve cells)

4) retinal folds

Bilateral enlarged blind spots (early)

12

What are the long term signs of papilloedema?

Irreversible atrophic changes of the optic disk

with

Gradual field loss (late) due to generalised constriction of the optic nerve

13

What is arteritic anterior ischemic optic neuropathy (AION)?

inflammation of the arteries to the optic disc

which causes infarction

14

Explain the detailed pathophysiology of arteritic AION.

giant cell (aka temporal) arteritis

where inflammation of the temporal arteries causes occlusion of the

posterior ciliary artery supply to the optic nerve

it hence gets infarcted.

15

What are the early signs of arteritic AION?

temporal headache and jaw claudication (due to jaw ischemia).

This happens before the optic infarction

Raised CRP and ESR

16

What is the Ix/Mx for a patient with arteritic anterior ischemic optic neuropathy (AION)?

Mx:
Urgent high dose steroid (or eye will do within 3 weeks) continued for at 2 YEARS.

Ix:
Temporal artery biopsy. Within 1 week of starting steroid to give a conclusive diagnosis.

17

What are the signs of arteritic AION?

disk is pale/white

the margins are blurred

the cup is obliterated and will not be visible

The rest of the fundus will have pallor

18

What is non-arteritic anterior ischemic optic neuropathy (AION)

A swollen artery, usually due to atherosclerosis. (i.e. due to CV risk factors not from giant cell arteritis)

This causes obliteration of the lumen of the posterior ciliary arteries and the optic nerve gets infracted

19

What are the features which can be used to differentiate arteritic and non-arteritic AION?

Artertic has a higher level of swelling and

the visual impairment is worse in arteritic

ESR is not raised in non-arteritic as it is not inflammatory

20

What are the at-risk groups for developing non-arteritic AION?

Hypertensives (50% of pts)

Diabetics

21

What is the treatment for non-arteritic AION?

Low-dose aspirin

22

What causes optic atrophy and what are the signs on fundoscopy and otherwise?

Anything that causes a disruption/compression of the blood supply to the optic nerve,

will produce optic atrophy

The signs are pale optic disk and RAPD

23

Describe the pupil light reflex pathway.

Light stimulates the retinal ganglion cells after reaching the light receptors.

This passes down the optic nerve

This goes to the pre tactile nucleus

and then signals are sent to the Edinger-Westphal nucleus on the same and contralateral side.

The signals then pass along parasympathetic neurones along the oculomotor nerve (CN3)

This synapses with the ciliary ganglion cells which

sends short ciliary nerves to the sphincter pupillae causing constriction of the pupil

24

Describe the pupil near reflex

Information from the light on each retina is taken to the occipital lobe via the optic nerve and optic radiation


where it is interpreted as vision

The peristriate area 19 interprets accommodation

and sends signals bilaterally to the Edinger-Westphal nucleus

it then follows the same pathway as for the light reflex

(vision is not a necessity for this reflex)

25

What is an afferent pupillary defect?

A total defect in the afferent pathway:

from retinal ganglion cells to the Edinger-Westphal nucleus.

Clinically this means pathology affecting the retina or optic nerve (before the optic chiasm)

26

What is a relative afferent pupillary defect?

This is similar to APD but is not complete so a minimal slower response will be noticed

as shown with a swinging flashlight test

27

What causes Horner's syndrome?

a lesion affecting the sympathetic supply to the eyes

28

What are the signs of Horner's syndrome?

Affected eye:
Smaller pupil (paralysis of dilator pupillae)
Ptosis (due to paralysis of sympathetic smooth muscle of the eye lid; superior tarsal muscle, this can also be known as Müller’s muscle but is "less" correct)

29

What should one check for in general inspection in a pupil examination?

1) Neck scars --> to look for surgery that may have damaged the sympathetic chain

2) Ptosis (could be due to 3rd nerve palsy or Horner's)

3) anisocoria

30

Expain the course of the sympathetic pathway to the eye?

1st order neurone: hypothalamus to C7-T1

2nd order neurone (preganglionic):
C7-T1

through the brachial plexus over pulmonary apex and synapses with

superior cervical ganglion (at the angle of manible/bifurcation of carotid artery)

3rd order neurone (postganglionic)

From superior cervical ganglion goes through the adventitia of the carotid artery and enter the cranium to reach the eye.

It innervates the:
Dilator muscles of the iris
Superior tarsal muscle

31

What is the cause of Argyll Robertson pupils?

Tertiary syphilis (neurosyphilis affecting the midbrain)

32

What are the signs of Argyll Robertson pupils?

Bilaterally small pupils that dont respond to light

Light-near dissociation (is a negative reaction to light but a positive reaction to accommodation)

Optic atrophy

33

What are the symptoms of Argyll Robertson pupils?

Blindness due to optic atrophy
Can present with uveitis

34

What is Adie's pupil?

unilateral
dilated pupil
in an otherwise health patient

It is thought to be due to a viral/bacterial infection of the ciliary ganglion and autonomic system

35

What are the signs for Adie's pupil?

poor pupil response to light

and

a slow response to accommodation

36

Who does Adie's pupil typically occur in?

young women