DIS - Optic Nerve IV - Week 10 Flashcards
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
Are toxic and nutritional neuropathies acute or chronic?
Slow, chronic progressive loss
-takes months eather than days/weeks
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
What kinds of workplace chemicals can potentially aggravate toxic/nutritional neuropathies (7)?
Glues
Lead
Pesticide
Radiators
Paints
Solvents
Plastics
What two aspects of dietary intake can potentially aggravate toxic/nutritional neuropathy?
Malnutrition
Ingestion of food containing toxins
List three vitamin and mineral deficiencies that can aggravate toxic/nutritional neuropathy.
Vitamin B12
Folate
Copper
List four systemic medications that can aggravate toxic/nutritional neuropathy.
Digitalis
Chloramphenicol
Chloroquine
Phenothiazine
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
What may be one of the first signs of toxic/nutritional neuropathy and is it proportionate to VA loss?
Dyschromatopsia
-disproportionate to VA loss
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
What eventually happens to the ONH with toxic/nutritional neuropathy? What happens initially?
Diffuse optic disc pallor
Begins temporally initially
What ocular motility problems may occur with toxic/nutritional neuropathy?
Nystagmus
What may be seen at the macula with toxic/nutritional neuropathy?
Crystal deposits
What kind of haemorrhages may be seen with toxic/nutritional neuropathy?
Flame haemorrhages
What may happen to the RPE with toxic/nutritional neuropathy (appearance)?
Salt and pepper fundus
What corneal changes may occur with toxic/nutritional neuropathy?
Corneal pigment deposits
What may happen to the retinal blood vessels with toxic/nutritional neuropathy?
Small retinal vessel tortuosity - telangiectasia
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
What are two possible treatment options for toxic/nutritional neuropathy?
Zinc and vitamin B supplements
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
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
What is generally the cause of chronic blood flow compromise? Explain (4).
Hypoperfusive
-low arterial pressure reduces blood flow
List three possible causes of reduced or slowed down blood flow.
Compromised metabolism
Local inflammatory response
Blood vessel wall damage
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
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
