DIS - Optic Nerve III - Week 10 Flashcards Preview

OD3 - Clinical Optometry Practice > DIS - Optic Nerve III - Week 10 > Flashcards

Flashcards in DIS - Optic Nerve III - Week 10 Deck (83)
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1
Q

Do inherited neuropathies always manifest at birth?

A

no, they may not manifest until later in life

2
Q

What is the major acquired optic neuropathy?

A

Glaucoma

3
Q

Define neuropathy.

A

Ongoing and premature loss of optic nerve fibres beyond normal ageing

4
Q

What is the end point of any neuropathy?

A

Atrophy

5
Q

Differentiate between papilloedema and optic disc oedema.

A

Papilloedema - bilateral swollen discs due to raised intracranial pressure
Optic disc oedema is generalised oedema with many other causes

6
Q

Describe the timeline of acute and chronic neuropathy to atrophy (3 each).

A

Acute - disc oedema, vascular compromise, necrosis > optic atrophy
Chronic - apoptosis, loss of nerve fibres, cupping/pallor > optic atrophy

7
Q

Describe the stages of disc oedema by the amount of disc involved (3).

A

Partial
Sectoral
Total

8
Q

Describe the stages of disc oedema by the visibility of vessels and structures (2).

A

Early - majority of structures visible

Severe - obstructed view

9
Q

Compare the appearance of acute and chronic disc oedema.

A

Acute - messy

Chronic - clean, champagne cork

10
Q

List five tests that assess optic nerve function.

A
Swinging flashlight test
Monocular vision
Monocular colour vision loss (ishihara)
Colour comparison - red cap
Brightness comparison (max brightness on ophthalmoscope, same principle as red cap testing)
11
Q

Are inherited optic neuropathies common or rare? Are they easily diagnosed or commonly misdiagnosed?

A

Rare and often misdiagnosed

12
Q

List the three main modes of inheritence for inherited optic neuropathies.

A

Autosomal recessive
Autosomal dominant
Mitochondrial

13
Q

In what three ways could other cases be ruled out for inherited optic neuropathies.

A

Serology
Imaging
Dilated fundus exam

14
Q

What mode of inheritence does Behrs syndrome have and how does it affect vision and from what age?

A

Autosomal recessive

Profound vision loss in neonates

15
Q

What appearance does the disc have in behrs syndrome?

A

Chalky white disc

16
Q

True or false

Nystagmus is not present with behrs syndrome

A

False, it is

17
Q

Can a foveal reflex be seen with behrs syndrome?

A

No

18
Q

What colour deficiency is present with behrs syndrome?

A

Red-green

19
Q

List three systemic abnormalities of behrs syndrome.

A

Spastic gait
Ataxia
Mental handicap

20
Q

What mode of inheritence does wolfram syndrome have?

A

Autosomal recessive

21
Q

What kind of atrophy does wolfram syndrome have?

A

Diffuse severe optic atrophy

22
Q

What is DIDMOAD and what disease is it for?

A
Diabetes insipidus
Diabetes mellitus (type 1)
Optic atrophy
Deafness
For wolfram syndrome
23
Q

List four systemic associations of wolfram syndrome. How does it affect lifespan?

A
Ataxia
Short stature
Endocrine anomalies
Mental impairment
Short lifespan
24
Q

What mode of inheritence does kjers disease have?

A

Autosomal dominant

25
Q

What effect does kjers disease have on vision and at what age?

A

Mild chronic loss

26
Q

How does the optic disc appear with kjers disease and what area specifically?

A

Temporal disc pallor

27
Q

What kind of visual field defect occurs with kjers disease?

A

Relative central scotoma

28
Q

What colour deficiency does kjers disease cause?

A

Blue-yellow

29
Q

Are other neurological abnormalities common with kjers disease?

A

Uncommon

30
Q

What is the most common inherited optic neuropathy?

A

Kjers disease

31
Q

What is the most common mitochondrial disorder?

A

Lebers hereditary optic neuropathy

32
Q

Between males and females, which is more affected by lebers hereditary optic neuropathy?

A

Males

33
Q

How does lebers hereditary optic neuropathy affect vision?

A

Profound vision loss in young adults from 6/24 to NLP

34
Q

What kind of visual field defect is present with lebers hereditary optic neuropathy?

A

Absolute central scotoma

35
Q

What colour vision defects are present with lebers hereditary optic neuropathy (2)?

A

Early blue-yellow then red-green defects

36
Q

What happens to the optic nerve with lebers hereditary optic neuropathy?

A

Normal disc > optic atrophy with time

37
Q

How does the optic disc margin appear with lebers hereditary optic neuropathy initially?

A

Initially circumpapillary telangiectasia

38
Q

What is the treatment for inherited optic neuropathies?

A

Often no treatment, so focus on assistance for legally blind individuals

39
Q

How should patients with positive family history for inherited optic neuropathies be managed? What about negative? What else should be considered (2)?

A

Positive - refer for genetic counselling
Negative - refer for serology and imaging
Manage systemic issues (diabetus/endocrine)
Vocational guidance - colour vision deficiency

40
Q

What is the normal ICP in the supine and upright positions?

A

Supine - 5 to 15mmHg

Upright 2 to 10mmHg

41
Q

How is raised ICP typically diagnosed?

A

Lumbar puncture - invasive and painful

42
Q

What is the most common cause of raised ICP?

A

A mass such as a tumour, haemorrhage, abcess, or oedema

43
Q

List four things that can increase venous pressure.

A

Coughing
Valsalva manoeuvre
Heart failure
Jugular vein obstruction

44
Q

Blockage to what two structures can cause altered CSF flow and subsequently raised ICP?

A

Blockage in the ventricles or subarachnoid space

-results in hydrocephalus

45
Q

What two thing may result in increased CSF production.

A

Meningitis

Tumour

46
Q

List four causes of raised ICP aside from mass.

A

Increased venous pressure
Altered CSF flow
Increased CSF production
Idiopathic intracranial hypertension

47
Q

What is pseudotumour cerebri?

A

Idiopathic intracranial hypertension

48
Q

Where can compression of the visual pathway occur?

A

Intracranially

Intraorbitally

49
Q

What is foster-kennedy syndrome? What does this syndrome present the only case of? Explain why this is so.

A

One eye has compressive neuropathy
Fellow eye has papilloedema
-only case where papilloedema is not bilateral
-this is because an atrophic optic nerve is no longer able to manifest the optic disc oedema

50
Q

List three causes of foster-kennedy syndrome.

A

A mass in the following regions:
Frontal lobe
Olfactory groove
Sphenoid wing meningioma

51
Q

List 9 neurological signs of foster-kennedy syndrome.

A
Severe/different constant headaches (sudden onset, thunderclap)
Gait problems (unsteady)
Projectile vomiting/nausea
Hemiparesis
Reduced alertness/consciousness
Brief visual disturbances (~30s)
Diplopia
Symptoms worse with posture change
Back/neck pain
52
Q

Is pupil abnormality a sign of foster-kennedy syndrome?

A

Yes

53
Q

How do intracranial masses raise ICP? Why does the RNFL swell?

A

They are a space-occupying lesion, and raised ICP is transmitted along the subarachnoid space, to the lamina
Compression at the lamina causes axoplasmic stasis, causing swelling

54
Q

Aside from affecting the nerves, what else is affected with compression along the optic nerve? Most markedly which region and why? What happens to the disc and nearby blood vessels?

A

Compression along the optic nerve gives venous compromise
Most markedly inferior due to gravity
Disc hyperaemia and buried blood vessels can be seen

55
Q

What happens to the veins specifically with venous compromise due to optic nerve compression (consider SVP)?

A

Venous engorgement

-no SVP with digital pressure

56
Q

What happens to the peripapillary region with venous compromise due to optic nerve compression?

A

Peripapillary haemorrhages

57
Q

Can cotton wool spots be seen with venous compromise due to optic nerve compression?

A

Yes

58
Q

What is a cotton wool spot?

A

Nerve fibre layer infarct

59
Q

Can papilloedema be seen with venous compromise due to optic nerve compression?

A

Yes

60
Q

What can changes can be seen on the retina and choroid with venous compromise due to optic nerve compression?

A

Retinal or choroidal folds

61
Q

What is an initial sign of compressive neuropathy?

A

Mild disc oedema

62
Q

List four long term signs of compressive neuropathy.

A

Compensated with established shunts
Champagne cork clean appearance
Gross intravitreal swelling of the ON
Venous flow not compromised, but axoplasmic stasis still present

63
Q

How does the retina appear with non-compensated compressive neuropathy?

A

Very dirty looking with haemorrhage and cotton wool spots

64
Q

List 8 other causes of papilloedema.

A
AIDS
Congenital hydrocephalus
Hypertension
Infectious meningitis
Inflammatory neuritis
Trauma
Aneurysm or haemorrhage
Idiopathic
65
Q

What is an aneurysm?

A

Abnormal swelling or bulging in a blood vessel wall

66
Q

What is the mortality of aneurysms or haemorrhages? Are they an emergency?

A

50%

-is an emergency

67
Q

Why is the location of major cerebral blood vessels important in the context of how aneurysms and haemorrhages affect vision?

A

They often involve the visual pathways, either directly or through transmitted ICP

68
Q

List four signs of an impending aneurysm rupture.

A

Thunderclap headache
Photophobia
Vision loss
Back/neck pain

69
Q

How long does it generally take for a rupture to occur (give range) and what is the median length?

A

1 day to 4 months

-median 14 days

70
Q

What 7 signs should you look for when suspecting an aneurysm or haemorrhage?

A
Vision loss
Pupil involvement
Lid anomaly
Extraocular muscle palsy
ON atrophy (with/without cupping)
Papilloedema
Intraorbital haemorrhage
71
Q

What should you beware when suspecting aneurysm or haemorrhage?

A

Head/brow/orbital pain that doesnt fit a recognised pattern

72
Q

What demographic does pseduotumour cerebri typically affect (3)?

A

Premenopausal obese women

73
Q

What are the signs of pseudotumour cerebri (3)?

A

As per papilloedema

  • all investigations fail to find a cause (MRI/CT/LP)
  • few neurological signs aside from severe headaches (90%)
74
Q

What percentage of pseudotumour cerebri have severe vision loss?

A

15 to 25%

75
Q

What can pseudotumour cerebri with CN6 involvement result in?

A

Double visiond

76
Q

What kind of diagnosis is pseudotumour cerebri?

A

Diagnosis by exclusion

77
Q

How should patients with suspected pseudotumour cerebi be managed?

A

Refer to the hospital for urgent medical workup

78
Q

What is the prognosis like for pseudotumour cerebri?

A

Good if ICP is reduced

79
Q

List 7 treatment options for pseudotumour cerebri?

A
Diuretics
Repeated lumbar puncture
Carbonic anhydrase inhibitors
Steroids
Weight reduction
Surgical shunting of CSF to jugular
Optic nerve decompression
80
Q

When assessing compressive neuropathies, what should you do and look out for? What three neurological tests should you do?

A

Dilated fundus exam for comprehensive ONH evaluation
Visual fields
Ocular motility
Pupil testing

81
Q

When should papilloedema be referred? How should they be monitored? What should be measured?

A

Urgent referral to GP or neuro-ophthalmologist within 1 week
Monitor daily to see if anything develops
Measure blood pressure

82
Q

What should you do if you see papilloedema with neurological signs?

A

Emergency referral to the hospital

83
Q

What should you do with patients with chronic unexplained pain with compressive neuropathy? What about acute,severe, and sudden onset?

A

Non-urgent referral to a neuro-ophthalmologist

If acute, severe, sudden onset - emergency referral

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