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(2) Tri B - Clinical opthalmology > Week 2 - Neuro 1.3 > Flashcards

Week 2 - Neuro 1.3 Flashcards

1
Q

What are the differential diagnosis of a raised disc?

A

• Compression
• Infiltration
• Congenital optic neuropathies (Leber’s optic neuropathy)
• Toxic optic neuropathies (methanol poisoning)
• Traumatic optic neuropathy

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2
Q

What are orbital compressive lesions and their symptoms?

A

Orbital masses may compress optic nerve and venous drainage

Symptoms:
• Monocular
• Slow, compressive, visual loss
- may be central or diffuse

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3
Q

What are associated signs/symptoms of orbital compressive lesions?

A

• Eyelid oedema
• Proposis
• Extraocular muscle involvement

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4
Q

What affect do orbital compressive lesions have on Pupils, Disc and vasculature appearance?

A

• Pupils : RAPD
• Disc Appearance:
- If anterior lesion, get disc oedema
- If intraorbital / intracanalicular, get disc pallor
• Vasculature not compromised; optic nerve dysfunction and atrophy despite no preceding disc oedema
• May have simple oedema or visible signs of infiltration
• Optocilliary shunt vessels

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5
Q

How are orbital compressive lesions investigated?

A

• Hospital investigations:
MRI and CT conducted if lesion suspected

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6
Q

what are the 3 main types of orbital compressive lesions?

A

• Optic nerve sheath meningioma
• Optic nerve glioma
• Melanocytoma

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7
Q

What is an Optic Nerve Sheath Meningioma?

A

• Benign tumour
• Proliferation of meningoepithelial cells lining the sheath of the optic nerve
• One third of optic nerve tumours
• Mean age of presentation: 40-50yrs
• Female > Male (as are meningiomas elsewhere)

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8
Q

What are Optic Nerve Sheath Meningioma: symptoms/signs?

A

• Painless, slowly progressive monocular visual loss (95% of cases)
• Proptosis (60-90% of cases)

• Disc appearance:
- Optic oedema then atrophy
- Optociliary shunt vessels

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9
Q

How is optic nerve sheath meningioma treated and their complications?

A

• Radiotherapy:
Stability or improvement in up to 94%
Complications:
- Radiation retinopathy
- Pituitary dysfunction

• Surgery:
Biopsy or excision
- Risk of optic nerve trauma and visual loss
- Considered if intracranial extension

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10
Q

What is Optic Nerve Glioma?

A

• Usually pilocytic tumours
• Most common primary tumour of optic nerve

• Most are slow growing and benign
• Some are malignant and more rapidly progressing, causing blindness and death

• 70% detected during first decade of life, 90% by second
• Associated with Neurofibromatosis 1, 10-30% of NF1 have Glioma, 10-70% of Glioma have NF1

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11
Q

What are the presenting symptoms and signs of Optic Nerve Glioma? (no Visual field)

A

Proptosis - 94%
Visual loss - 87%
Strabismus - 27%

Optic disc pallor - 59%
Disc oedema - 35%

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12
Q

What are the signs of optic nerve glioma?

A

• RAPD
• Visual field defect
• Optociliary shunt vessels

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13
Q

How is optic nerve glioma managed in hospital?

A

• Observation if good vision and stable imaging appearance
• Chemotherapy when visual loss severe
• Radiotherapy has a risk of complications including pituitary dysfunction

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14
Q

What is Optic Nerve Melanocytoma?

A

• Pigmented tumour of uveal tract
• Predilection for lamina cribrosa of optic nerve head

• Typically benign composed of melanocytes and melanin and don’t grow
- Rarely become malignant

Presentation:
• Can get optic nerve dysfunction if large but usually a coincidental finding

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15
Q

what are the signs of Optic Nerve Melanocytoma?

A

• Black lesion with feathery edges
• Typically small and don’t grow

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16
Q

What are the complications and treatment of optic nerve melanocytoma?

A

Complications:
- Central retinal vein occlusion
- Malignant transformation

Hospital treatment
- Observation every 6-12months

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17
Q

What are infiltrative lesions, their symptoms and signs?

A

• Infiltration / invasion of optic nerve by neoplastic or inflammatory cells
• Ocular involvement may be presenting feature of systemic disease

• Symptoms:
- Progressive, severe visual loss over days to weeks
- Associated with headache

• Signs
- Retrobulbar infiltration - disc appears normal
- Disc involvement - swollen appearance

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18
Q

What are some of the causes of infiltrative lesions?

A

• Leukaemia
• Lymphoma
• Granulomatous infiltration
- Sarcoidosis, TB, syphilis
• Metastases
- rare but most commonly from breast or lung cancer

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19
Q

How are infiltrative lesions investigated? And why are they done?

A

• MRI of brain and orbits
• CSF analysis
• Screening tests for inflammatory / infective / neoplastic disorders

• Early identification allows life saving treatment
• Palliative care may improve vision if poor prognosis

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20
Q

What is Leber hereditary optic neuropathy?

A

• Hereditary condition characterised by bilateral optic atrophy
• Affects maternal mitochondrial DNA
• Males, 10-30 years

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21
Q

What are Leber Hereditary Optic Neuropathy symptoms/signs?

A

• Ask about family history
• Acute, severe, painless visual loss (<6/60)
• Initially monocular but both involved
• Central / centrocecal visual loss
• RAPD when monocular involvement

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22
Q

What is the disc appearance of Leber Hereditary Optic Neuropathy?

A

• Normal in up to 40%
• Hyperaemia and elevation of disc
• Thickening of peripapillary retina
• Peripapillary telangiectasia
• Tortuosity of medium sized retinal vessels
• Eventual optic atrophy

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23
Q

How is Leber Hereditary Optic Neuropathy managed?

A

• MRI scan to exclude a treatable cause
• Once diagnosed no treatment and visual loss usually permanent

24
Q

What is toxic/nutritional optic neuropathy?

A

• Typical history is of alcohol and/or tobacco excess with neglect of diet
(B vitamins & thiamine
• Can get neuropathy in well nourished individuals with pernicious anaemia or vitamin B12 deficiency

• Other meds associated with conditions include Methanol (antifreeze) Cardiac arrhythmia, breast cancer, tuberculosis and acne mediation.

25
what are the symptoms of toxic/nutritional optic neuropathy?
• Chronic (gradual & progressive) or acute, depending upon the cause • Bilateral and symmetrical • Painless visual loss • Dimness of vision
26
What are some signs of toxic/nutritional optic neuropathy?
• Affects central vision with central / caecocentral scotoma initial presentation: • Optic disc can be normal / mild pallor / hyperaemia - patients with hyperemic discs, could get small splinter hemorrhages on disc edge • Mild depression on Amsler fixation target • Reduced colour vision Months-years after presentation: • papillomacular bundle dropout • temporal disc pallor followed by optic atrophy
27
how is toxic/nutritional optic neuropathy investigated and treated?
Investigations of exclusion: • Fluorescein angiography • Blood testing • Electrophysiology • MRI imaging Treatment • Reversal of cause - Can get reversal of ocular signs if optic atrophy has not progressed too much
28
What is Traumatic optic neuropathy?
Optic nerve damage from trauma to head / orbit / globe Direct traumatic optic neuropathy • Avulsion of nerve from laceration by bone fragments / foreign bodies • Direct compression from hemorrhage Indirect traumatic optic neuropathy • Shear forces on nerve • Shear forces on vascular supply
29
What scenarios are found during the examination with Px’s with Traumatic Optic Neuropathy?
• Visual loss - Immediate - Severe - no perception of light • RAPD • Optic disc - If posterior pathology may appear normal Eventual atrophy • Neuroimaging - Assesses extent of injury and co-morbidity
30
How is Traumatic optic neuropathy managed?
• Neuroimaging to assesses extent of injury and co-morbidity • Therapy controversial • Prognosis poor • Intravenous steroids • Anti-inflammatory and neuroprotective - Increased risk of mortality when combined with other head injuries - Consider when isolated injury with no other evidence of head injury
31
What are other conditions that cause the APPEARANCE of a raised optic disc? (non-intraocular disease)
• Optic disc drusen • Tilted optic disc •Myelinated nerve fibres • Hypermetropic crowded disc
32
What are other conditions that cause the APPEARANCE of a raised optic disc? (intraocular disease)
• Central retinal vein occlusion • Posterior uveitis • Posterior scleritis • Hypotony
33
What is optic disc drusen and their symptoms?
• Calcified nodules within optic nerve head • 0.34% - 2% of population • Bilateral in 75% • Unclear pathophysiology - ? Impaired ganglion cell axonal transport • Buried in childhood, more prominent with age • Symptoms Most patients asymptomatic
34
What might be found during the ocular examination with drusen in visual fields and RAPD?
• Visual fields - Visual field loss in 75 - 87% - Enlarged blind spot / arcuate defect - Remains stable or very slowly preogresses • RAPD - Possible RAPD if monocular/asymmetric
35
What might be found during the ocular examination with drusen in the optic disc?
• Appears small in diameter • Anomalous branching vascular patterns • Round, whitish, yellow refractive bodies • Disc may be pale / atrophy /RNFL loss
36
What is the difference between buried drusen vs swollen disc and how can they be told apart?
Both may elevate the disc and blur its margins, however:- Optic disc drusen: • Lack of hyperaemia • Lack of microvascular changes • Normal / atrophic nerve fibre layer • Anomalous retinal vascular patterns B-scan, Fluorescein angiography and MRI can be used to differentiate between them
37
How is optic disc drusen treated?
• None! More dangerous to remove than to just not treat.
38
What is a tilted optic disc?
• 1-2% of the population • 80% bilateral • Congenital or associated with myopia • Oblique insertion of optic nerve • Normal vision
39
How does the disc appear during examination of Tilted optic disc?
• Oval, tilted appearance • Inferior peripapillary atrophy
40
How does the visual field appear during examination of Tilted optic disc?
• Can have Bitemporal loss • Superior arcuate scotoma
41
What are myelinated nerve fibres?
• 1% of population • The nerve fibres are myelinated within the optic nerve and the myelin sheath usually stops at the lamina cribrosa • Unilateral in 80%
42
What are the signs and symptoms of myelinated nerve fibres?
• Symptoms Usually asymptomatic • Signs - Funds examination: Visible yellow patch of myelin around nerve head - Visual fields: enlarged blind spot corresponding to area of myelin
43
What the types of excavated optic disc anomalies?
• Optic disc pit • Colobomas • Optic nerve hypoplasia • Morning glory disc anomaly
44
What is an optic disc pit and what can it cause?
• Congenital (failure of foetal fissure) • Depression of disc surface • Associated with visual field defect Risks: • Serous macular detachment - Communication between optic pit and macula - Liquified vitreous or subarachnoid fluid - Greyish appearance, temporal / inferior disc • Associated central vision loss when situated on maculopapular bundle
45
How is optic disc pit managed in the hospital?
• Difficult, however Options include: - Observe (25% spontaneously resolve, some develop macular involvement) - Argon laser along temporal aspect of disc - Pars plana vitrectomy (air / fluid exchange with posturing)
46
What is a coloboma?
• Congenital defect from incomplete closure of the embryonic fissure - Unilateral or bilateral - Usually occur inferiorly
47
What are the Visual acuity, visual fields and fundus findings during an examination of coloboma?
• Visual acuity - Reduced • Visual Fields - Superior field defect - Can mimic glaucomatous loss • Fundus - Larger than normal optic discs - Can involve uvea and retina
48
What are some associations and complications of coloboma?
• Associations - Microphthalmos - Colobomas of iris, choroid, retina • Complications - Serous / rhegmatogenous retinal detachment - Progressive neuroretinal rim thinning
49
What is optic nerve hypoplasia?
• Reduced number of nerve fibres In isolation (by chance), part of malformed eye or associated with: • Midline structures of the brain • Endocrine abnormalities - growth hormone and other pituitary hormones • Suprasellar tumours
50
What are optic nerve hypoplasia predisposing factors?
• Diseases; - Maternal diabetes, • Drugs and Agents; (agents ingested by mother during pregnancy) - alcohol, LSD, quinine, steroids, diuretics, anticonuuissants, cold remedies...
51
How does Optic nerve hypoplasia present in bilateral and unilateral cases?
Bilateral cases: • Nystagmus eye movements • Sluggish pupil responses Less severe bilateral cases: • Squint • Minor visual field defects Unilateral cases: • Squint • RAPD • Unsteady fixation in affected eye
52
What are the visual field and disc findings during the examination of optic nerve hypoplasia?
• Visual Fields Peripheral and arcuate defects • Disc appearance - Small diameter of disc - Grey disc colour and surrounding hypopigmentation - Relatively large retinal vessel diameter - Ratio of disc diameter:disc-fovea >3:1
53
How is optic nerve hypoplasia managed in hospital?
• MRI in all cases • Referral for endocrine opinion
54
What is the morning glory anomaly?
• Rare congenital malformation, embryonic origin unclear • Funnel-shaped staphylomatous excavation of the optic nerve • Usually unilateral • More common in females
55
What are the visual field and fundus findings during examination of Morning glory anomaly?
• Visual acuity <6/60 • RAPD • Visual field loss • Serous retinal detachment • Fundus - Enlarged disc - Disc pink or orange colour - Chorioretinal pigmentation around excavation - White glial tissue on central disc surface - Retinal vessels appear at periphery of disc

(2) Tri B - Clinical opthalmology (10 decks)

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