DIS - Optic Nerve IV - Week 10 Flashcards by B H

List two ways in which build up of toxic substances can lead to dysfunction.

Can interfere with ATP bioavailability
Can lead to ion channel dysfunction

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Are toxic and nutritional neuropathies acute or chronic?

Slow, chronic progressive loss
-takes months eather than days/weeks

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List 6 aggravating factors for toxic and nutritional neuropathies.

Heavy alcohol use
Heavy smoking
Recreational and illicit drug use
Exposure to workplace chemicals
Dietary intake
Use of systemic medications

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What kinds of workplace chemicals can potentially aggravate toxic/nutritional neuropathies (7)?

Glues
Lead
Pesticide
Radiators
Paints
Solvents
Plastics

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What two aspects of dietary intake can potentially aggravate toxic/nutritional neuropathy?

Malnutrition
Ingestion of food containing toxins

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List three vitamin and mineral deficiencies that can aggravate toxic/nutritional neuropathy.

Vitamin B12
Folate
Copper

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List four systemic medications that can aggravate toxic/nutritional neuropathy.

Digitalis
Chloramphenicol
Chloroquine
Phenothiazine

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If affected by toxic/nutritional neuropathy, would you expect it to be uni- or bilateral? Would pain be involved? What happens to the RNFL? What is a consequence of this (include what section of the ONH involved)?

Bilateral and painless
Papillomacula RNFL loss
Temporal optical atrophy
-due to injured papillomacular bundle

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What may be one of the first signs of toxic/nutritional neuropathy and is it proportionate to VA loss?

Dyschromatopsia
-disproportionate to VA loss

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How are visual fields typically affected with toxic/nutritional neuropathy (2)? What VF test would you consider doing?

Central or cecocentral scotoma
-consider 10-2

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What eventually happens to the ONH with toxic/nutritional neuropathy? What happens initially?

Diffuse optic disc pallor
Begins temporally initially

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What ocular motility problems may occur with toxic/nutritional neuropathy?

Nystagmus

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What may be seen at the macula with toxic/nutritional neuropathy?

Crystal deposits

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What kind of haemorrhages may be seen with toxic/nutritional neuropathy?

Flame haemorrhages

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What may happen to the RPE with toxic/nutritional neuropathy (appearance)?

Salt and pepper fundus

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What corneal changes may occur with toxic/nutritional neuropathy?

Corneal pigment deposits

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What may happen to the retinal blood vessels with toxic/nutritional neuropathy?

Small retinal vessel tortuosity - telangiectasia

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What should you do if you suspect toxic/nutritional neuropathy (4)? What referral can be made?

Dilated fundus exam
-rule out other retinal causes
Extensive history taking
Check VA
Patient education
-need to stay clean of drugs
Referral to GP for serological testing and treatment

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What are two possible treatment options for toxic/nutritional neuropathy?

Zinc and vitamin B supplements

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Would you expect ischaemic neuropathy to occur following closure of the short posterior ciliary artery? Explain why. Mention what generally occurs with young patients regarding ischaemic insult and what happens with age.

Doesnt lead to ischaemic neuropathy due to many anastamoses
May explain why young patients are resistant to ischaemic insult
Ageing reduces autoregulatory capacity or collateral systems, increasing ischaemic potential

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What are two general causes of acute blood flow compromise? Explain.

Generally embolic
-blood clot or something else (gas bubble) becomes stuck in a blood vessel and obstructs flow
Thrombic
-inflammation > sticky platelets > blood clot develops > reduces flow

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What is generally the cause of chronic blood flow compromise? Explain (4).

Hypoperfusive
-low arterial pressure reduces blood flow

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List three possible causes of reduced or slowed down blood flow.

Compromised metabolism
Local inflammatory response
Blood vessel wall damage

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List the two types of ischaemic neuropathy, and note which is more common. For this type, note what structure it affects and what main vascular supply is involved.

Anterior and posterior
Anterior is more common
-affects the ONH
-main vascular supply - posterior ciliary arteries

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Is posterior ischaemic neurpathy commonly seen? What kind of diagnosis is it? What two regions does it involve and what is the main vascular supply involved?

Not often seen Diagnosis of exclusion Retrobulbar/intraorbital region affected Main vascular supply - pial vascular plexus

List the two types of anterior ischaemic optic neuropathy.

Arteritic Non-arteritic

What is the general cause of arteritic AION? What can it lead to (3)?

Generalised arterial inflammation affecting local arterial walls Leads to thrombus formation -can give embolus SPCA occlusion

What is the general cause of non-arteritic AION (3)? What can it lead to?

Low perfusion pressure at the ONH Local slowing down of blood Arterial ischaemia/wall compromise Leads to thrombus formation

List two possible mechanisms for arteritic AION.

Inflammation of arteries supplying the ONH leading to possible occlusion Inflammation due to giant cell (temporal) arteritis

What is rumbolds disease also known as? What is it and what is damaged? Why is it called giant cell arteritis?

Giant cell arteritis Degeneration of arterial smooth muscle Damage to elastic lamina Macrophages form giant cells, coalesce and ingest material

List 10 medium and large sized arteries that may be inflammed with giant cell arteritis, listing four of those with ocular involvement first.

SPCA LPCA CRA Cilioretinal artery (if present) Facial Temporal Carotid Verebral Renal Aorta

List 5 symptoms of giant cell arteritis due to cranial vessel involvement.

Headache Jaw claudication Scalp tenderness Loss of vision Abnormalities of the temporal artery

What is a symptom of giant cell arteritis due to involvement of great veseels (aorta and branches)?

Claudication of extremities -especially arm

List 3 symptoms of giant cell arteritis due to systemic involvement.

Fever Night sweats Weight loss

List 3 symptoms of giant cell arteritis due to polymyalgia rheumatica.

Proximal myalgia Neck stiffness Shoulder/pelvic girdles

What age population is more at risk of arteritic AION? What is the mean age?

Older people >50yo Mean age 75

Are men or women more at risk of arteritic AION?

Women more affected than men

List four ocular symptoms of arteritic AION.

Sudden painless vision loss -may not improve Transient ischaemic attacks, amourosis fugax Diplopia Flashes/flicker/colour scintillations

What visual field defect would arteritic AION cause?

Central scotoma

How does arteritic AION affect colour vision?

Achromatopsia Dyschromatopsia

Is RAPd present or absent with arteritic AION?

Present

What can be said of the peripapillary region with arteritic AION?

Non-perfusion

Describe two ways optic neuropathy of arteritic AION can appear.

Disc oedema, peripapillary haemorrhages, cotton wool spots White palid disc with mild peripapillary oedema

What should you do and look out for when assessing a suspected case of arteritic AION (3)?

Dilated fundus exam for comprehensive evaluation Fluorescein angiography to identify areas of non-perfusion Patient education

What percentage of all patients with arteritic AION achieve poor VA outcomes?

65%

Should arteritic AION be referred? Why?

Emergency referral to save fellow eye

Is arteritic AION life threatening?

Yes

What percentage of arteritic AION will become bilateral? what is this number if treatment is given?

40% 10% with treatment

List two diagnostic tests for arteritic AION.

ESR >50mm/h Temporal artery biopsy

What is the main treatment option for arteritic AION (2)? What percentage improve? Keeping the diagnostic tests in mind, should you wait for the diagnosis before commencing treatment?

Immediate oral or IV steroid treatment Majority (70%) improve Dont wait for the biopsy to return positive

Describe what non-arteritic AION is. What is it the most common cause of?

Non-inflammatory small vessel disease -acute choroidal hypoperfusion Most common cause of AION

Non-arteritic AION is more common in people with what?

Tight scleral sheaths

What is the age range and mean age for non-arteritic AION?

12 to 90, mean age 62

How does non-arteritic AION affect vision? Is pain involved?

Sudden painless vision loss (6/30)

What happens to the disc with non-arteritic AION? By how long can it precede vision loss? In what region is it most marked? What happens eventually?

Unilateral disc oedema Can precede vision by 1-4 months Most marked superiorly Optic atrophy ensues after 1-2 months

What visual defects may be present with non-arteritic AION (2)?

Altitudinal (inferior) or arcuate defects

Is RAPD present or absent with non-arteritic AION?

Present

How does non-arteritic AION affect colour vision (2)?

Red-green defect Red desaturation

What should you do and look out for with non-arteritic AION (4)?

Dilated fundus exam Visual field testing Fluorescein angiography to show areas of non-perfusion Patient education

What should you look out for when doing visual fields with non-arteritic AION? Is the horizontal hemifield margin generally sharp?

Inferior defects -relative inferior altitudinal -absolute inferior altitudinal -inferonasal absolute loss Horizontal margin usually ratty, not sharp

How should you refer non-arteritic AION and for what?

GP for systemic workup Ophthalmology for possible treatment

What is a possible treatment option for non-arteritic AION?

Aspirin for blood thinning, reducing risk to fellow eye

When dealing with non-arteritic AION, what is the benefit of measuring blood pressure?

Strong indication for stroke

List five predisposing health conditions or lifestyle choices for non-arteritic AION.

Heart problems Hypertension Diabetes Current smoker High cholesterol

List three other hypoperfusion problems.

Papillophlebitis Diabetic papilloapthy Low tension glaucoma

How do patients with papillophlebitis present (2)? What kind of patients are they?

Has the clinical features of a CRVO but with no history of vascular disease -they are young, healthy people

List 4 clinical features of papillophlebitis. What is the hallmark?

Hallmark perivenous sheath and exudate due to venous wall inflammation Mild-moderate vision loss Mild unilateral disc oedema Enlarged blindspot during acute phase

Does papillophlebitis present with RAPD? Does it cause colour vision deficiency?

Yes to both

List four features of the retina with phlebitis.

Chronic vitreal traction Veins swollen and sheathed Clean disc oedema Peripapillary and macular haemorrhages

What should you do and look out for when assessing papillophlebitis (2)?

Dilated fundus exam and fluorescein angiography

How should you refer a case of papillophlebitis (3)?

Refer for serology/imaging Refer to an ophthalmologist

What kind of diagnosis is papillophlebitis?

Diagnosis by exclusion

What is the treatment for phlebitis?

Systemic steroids

Is diabetic retinoapthy often present with diabetic papillopathy or do they rarely coexist?

Most often present (83%)

List 5 clinical features of diabetic papillopathy.

Mild/moderate VA loss Transient clean disc oedema Possible disc neovascularisation Peripheral telangiectasia Enlarged blindspot

Is RAPD present with diabetic papillopathy?

May or may not be

What should you do and look out for with diabetic papillopathy (2)?

Dilated fundus exam Fluorescein angiography

What is the treatment for diabetic papillopathy (2)?

Wait and see? High dose systemic steroids?

Does diabetic papillopathy have good prognosis?

Yes, is self-limiting

What must diabetic papillopathy be distinguished from if it is bilateral?

Papilloedema