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Ophthalmology > Ocular neurology > Flashcards

Ocular neurology Flashcards

1
Q

What are some cardinal features of neurological disease in the eye?

A
  • Eye movement defects (Double vision)
  • Visual defects (Visual acuity, field loss)
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2
Q

What are some causes of neurological disease of the eye?

A
  • Vascular disease
  • Tumours
  • Trauma
  • Demyelination
  • Inflammation/Infection
  • Congenital abnormalities
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3
Q

What investigations are required in suspected ocular neurological disease?

A
  • Full medical examination
  • Blood tests
  • Imaging - MRI
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4
Q

What is meant by sudden onset diplopia?

A
  • Patient has changed from having binocular single vision (seeing one image only) to a sudden onset manifest squint and diplopia (double vision)
  • The double vision will be horizontal, vertical, or both, due to new weakness of extra-ocular muscles
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5
Q

What tests are required in sudden onset diplopia?

A

Cover test
Ocular motility

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6
Q

What does eso- or exo- tropia on cover test suggest?

A

LR or MR problem

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7
Q

What does hyper- or hypo- tropia on cover test suggest?

A

SO, SR, IR, IO problem

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8
Q

What does visible sclera on full abduction or adduction of the eye suggest?

A

Occular muscle weakness

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9
Q

What muscle is tested for by each motility direction?

A
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10
Q

Which ocular muscles are supplied by CN III?

A

All extraocular muscles except superior oblique and lateral rectus

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11
Q

What are some causes of 3rd CN palsy?

A
  • Microvascular
  • Tumour
  • Aneurysm
  • MS
  • Congenital
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12
Q

How will 3rd CN palsy present?

A

Down and out appearance of the eye
Ptsosis
Miosis

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13
Q

Describe the pathophysiology of ocular changes in 3rd CN palsy

A

Results in the unopposed action of both the lateral rectus and superior oblique muscles, which pull the eye inferolaterally

Lack of innervation to levator palpebrae superioris leads to ptosis

Loss of parasympathetic fibres responsible for innervating to the sphincter pupillae muscle leads to miosis

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14
Q

What is the biggest worry in a pailful 3rd CN palsy?

A

Aneurysm

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15
Q

What is shown?

A

3rd CN palsy

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16
Q

What muscle is supplied by the 4th CN?

A

Superior oblique

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17
Q

What are the 3 actions of the superior oblique muscle?

A
  • Incyclo-torsion
  • Depression in adduction
  • Weak abduction
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18
Q

What are some causes of 4th CN palsy?

A
  • Congenital decompensated
  • Microvascular
  • Tumour
  • Blunt headtraumacan result in bilateral CN IV palsy
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19
Q

How will 4th CN palsy present?

A

Vertical diplopia when looking inferiorly due to loss of the superior oblique’s action of pulling the eye downwards
Affected eye turned upward in primary position

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20
Q

How may patients compensate for a 4th CN palsy?

A

Bilateral CN IV palsy = Chin-down head posture
Unilateral CN IV palsy = Contralateral head tilt

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21
Q

What is shown?

A

4th CN palsy

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22
Q

What is shown?

A

Chin-down head position to compensate for bilateral 4th CN palsy

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23
Q

What is shown?

A

Contralateral head tilt to compensate for unilateral 4th CN palsy

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24
Q

What ocular muscle is innervated by CN VI?

A

Lateral rectus

25
Q

What are some causes of 6th CN palsy?

A
  • Microvascular
  • Raised intracranial pressure
  • Tumour
  • Congenital
26
Q

How will 6th CN palsy present?

A

Horizontal diplopia worsened by looking towards the affected side
Unopposed adduction of the eye, resulting in esotropia

27
Q

What is shown?

A

6th CN palsy

28
Q

What is shown?

A

3rd CN palsy

29
Q

What is shown?

A

4th CN palsy

30
Q

What is shown?

A

6th CN palsy

31
Q

What is internuclear ophthalmoplegia?

A

Disorder of conjugate lateral gaze in which the affected eye shows impairment of adduction

32
Q

What are some causes of internuclear ophthalmoplegia?

A
  • Injury/dysfunction in the medial longitudinal fasciculus (tract which acts as the central connection for the oculomotor nerve, trochlear nerve, and oculomotor nerve)
  • In younger patients, MS is a common cause
  • Older patients generally have a vascular aetiology (stroke)
33
Q

How will internuclear ophthalmoplegia present?

A
34
Q

What is meant by homonymous?

A

Same sided

35
Q

What are some causes of visual field defects?

A
  • Vascular disease - CVA
  • Space occupying lesion (SOL) e.g. pituitary tumour
  • Demyelination (MS)
  • Trauma - including surgical
36
Q

What visual field defect will be caused by optic nerve damage?

A

Total unilateral visual loss

37
Q

What visual field defect will be caused by optic chiasm damage?

A

Bitemporal hemianopia

38
Q

What visual field defect will be caused by left optic tract damage?

A

Right homonymous hemianopia

39
Q

What visual field defect will be caused by left optic radiation damage?

A

Right homonymous upper quadrantanopia

40
Q

What visual field defect will be caused by left optic cortex damage?

A

Right homonymous hemianopia with macular sparing

41
Q

What are some causes of optic nerve defects?

A
  • Ischaemic optic neuropathy
  • Optic neuritis - commonly MS
  • Tumours (rare) - meningioma, glioma, haemangioma
42
Q

What are some features of optic neuritis?

A
  • Progressive unilateral visual loss
  • Pain behind eye, especially on movement
  • Colour desaturation
  • Central scotoma
  • Gradual recovery over weeks to months
43
Q

What is a possible complication of optic nerve defect?

A

Optic atrophy

44
Q

What is optic atrophy?

A
  • death of the retinal ganglion cell axons that comprise the optic nerve
  • End stage that arises from damage to the optic nerve of any cause
  • Results in a pale optic disc on fundoscopy
45
Q

What are some causes of optic chiasm defect?

A
  • Pituitary tumour - visual loss/distrubance commonly reversed after tumour decompressed/removed
  • Craniopharyngioma
  • Meningioma
46
Q

What are some causes of optic tract and radiation defects?

A
  • Tumours (primary or secondary)
  • Demyelination
  • Vascular anomalies
47
Q

What are some causes of occipital cortex defects?

A
  • Vascular disease (CVA)
  • Demyelination
48
Q

What is ischaemic optic neuropathy?

A

Occlusion of the posterior ciliary arteries, resulting in infarction of the optic nerve head

49
Q

What are some causes of ischaemic optic neuropathy?

A

Giant cell arteritis (Arteritic ION)
Non-arteritic ION

50
Q

How does ischaemic optic neuropathy present?

A
  • Sudden visual loss
  • Usually painless
51
Q

How does ischaemic optic neuropathy show on fundoscopy?

A

Pale, swollen disc

52
Q

What is papilloedema?

A

Swelling of the optic nerve due to increased intracranial pressure

53
Q

What are some causes of raised ICP?

A
  • Obstruction to CSF circulation (E.g. congenital malformation)
  • Overproduction of CSF (E.g. Choroid plexus tumour)
  • Inadequate absorption (E.g. Subarachnoid haemorrhage)
  • Space-occupying lesion
54
Q

What are some possible causes of idiopathic intracranial hypertension?

A

Increased abdominal pressure (Obesity)
Stenosis of transverse cerebral sinuses
Possible vitamin A problem
Microemboli in saggia sinus

55
Q

How does raised ICP cause papilloedema?

A
  • Optic nerve is extension of the brain (with meningeal sheaths)
  • Subarachnoid space around optic nerve is continuous with the subarachnoid space surrounding the brain
  • When intracranial pressure rises, this is transmitted to the subarachnoid space and then onto the optic nerve
  • This causes interruption of axoplasmic flow and venous congestion → swollen discs
56
Q

How will papilloedema present?

A
  • Headache
  • Enlarged blind spot, blurring of vision, visual obscurations and loss of vision
  • N+V, especially if ICP rise is acute
57
Q

What is shown?

A

Papilloedema - Disc swelling

58
Q

What is a possible complication of chronic papilloedema?

A

Optic atrophy → loss of visual function occurs and blindness may result

59
Q
A

Ophthalmology (9 decks)

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