Vascular disease: retinal artery occlusions Flashcards Preview

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Flashcards in Vascular disease: retinal artery occlusions Deck (18)
1

what causes a CRAO and possibly a BRAO

Occlusion of central retinal artery (CRAO), usually by a fibrin-platelet thrombus or an embolus.

Occlusion of branch retinal artery (BRAO) also possible

2

what other vascular disorders to retinal artery occlusions share it's risk factors with and list the 5 risk factors

factors with other vascular diseases e.g.

hypertension
hyperlipidaemia
tobacco use
atherosclerosis
Diabetes Mellitus

3

as well as occlusions of the CRA and BRA, what can be another cause to a CRAO or BRAO and name 2 conditions that can cause this

Can also be caused by vascular inflammatory conditions

e.g. giant cell arteritis, systemic lupus erythematosus

4

what does a CRAO/BRAO indicate
what is the life expectancy of someone with a CRAO compared to someone without a CRAO

Indicates increased risk of life-threatening cerebrovascular or cardiovascular incident.

Life expectancy 5.5 years compared to 15.4 years for age matched population without CRAO

5

what is the clinical presentations of a CRAO/BRAO

Sudden, severe, painless loss vision.

~90% px with CRAO have vision between counting fingers and light perception at presentation.

1-2% bilateral presentation.

Mean age early 60s.

May have history of amaurosis fugax (transient loss of vision lasting seconds-2 hours – vision returns to normal afterwards).

With branch occlusion, extent of visual loss will depend on location of occlusion.

6

what are the 5 signs of an acute CRAO/BRAO

Inner layers of the retina become oedematous and milky/opaque.

Opacity greatest at macula where RNFL and RGC layers thickest.

Ischaemic necrosis results from the disrupted blood supply

Fovea shows a ‘cherry red spot’ because fovea is nourished/being provided for by underlying choroidal circulation so it's not becoming ischaemic, and because retina is thinnest here so underlying choroid seen.

Blood moves sluggishly in occluded vessels and blood flow may appear segmented (‘boxcarring’ or ‘cattle tracking’)

7

what are the 3 signs of a chronic CRAO/BRAO

Retinal opacification evident within 15 mins-2 hours.
Resolves in 4-weeks.

Chronic appearance of attenuated retinal arterioles and optic nerve atrophy.

Homogenous scar replaces inner retinal layers

8

what is seen on the fundus in 20-40% of cases

embolus or thrombus seen

9

what is the appearance of 2 types of embolus and a thrombus seen on the retina in 20-40% of cases

- Glistening yellow cholesterol emboli often from atherosclerotic plaques in carotid artery

- Calcific emboli typically from cardiac valves

- non-glistening platelet-fibrin thrombus typically seen at optic disc

10

what 2 things can happen to an emboli and what may this emboli cause

Emboli may dislodge after causing temporary visual loss (amaurosis fugax) which will retire to normal

They may get trapped at a bifurcation/at branching of vessel and not obstruct flow.

May cause CRAO or BRAO.

11

what should you do with patients with retinal emboli or history of transient painless visual loss

should be referred for urgent cardiovascular assessment

12

what is the outcomes of a CRAO/BRAO

Visual loss usually severe.

Field defect most commonly central in CRAO – peripheral fields more likely to recover.

Any spontaneous recovery in vision usually occurs within first 7 days - beyond 7 days = visual loss is often permanent

In 10% of eyes with a cilioretinal artery supplying the fovea VA returns to 6/7.5 or better in 80% of eyes within 2 weeks.

Retinal or anterior eye neovascularisation may be possible longer term complications.

13

what will be your management of a patient seen with a CRAO/BRAO

OCULAR EMERGENCY!!!
- Any treatment outside 4 hour window unlikely to improve vision. If vision loss has occurred within last 24 hours
- phone casualty immediately.

In practice can do the following:
- Ask px to lie flat (raises pressure in ophthalmic artery)
- Ocular massage may help to dislodge the embolus – press on eye with heel of hand (10 sec on, 10 sec off for 5 mins).
- Can ask Px to breath into paper bag – increased CO2 levels will cause vasodilation and may help to dislodge the embolus
- But best to get them to casualty ASAP!

14

why you need to refer a px with CRAO/BRAO due to an emboli and due to arteritic inflammation cause urgently

Patients with CRAO/BRAO due to emboli are at high risk of stroke / heart attack – need urgent referral for medical assessment even if window of opportunity for vision restoration has passed.

Arteritic CRAO/BRAO due to temporal (giant cell) arteritis also needs urgent treatment. Visual outcome worse due to concurrent arteritic anterior ischaemic optic neuropathy

15

which cause of a CRAO/BRAO has a worse visual outcome and why

Arteritic due to temporal (giant cell) arteritis

ue to concurrent arteritic anterior ischaemic optic neuropathy

16

what is the ophthalmological aim of treating a CRAO/BRAO and which 2 ways is this achieved

Ophthalmologist will aim to increase perfusion pressure:

By reducing IOP

By causing vasodilation - to help dislodge the embolus

17

how does the ophthalmologist aim to increase perfusion pressure by reducing IOP in treating someone with a CRAO/BRAO
name 2 ways

Intravenous acetazolamide
or
Anterior chamber paracentesis (inserting needle into the anterior chamber and withdrawing 0.1 to 0.2 ml aqueous fluid.

18

how does the ophthalmologist aim to increase perfusion pressure by causing vasodilation to help dislodge the embolus in treating someone with a CRAO/BRAO
name 2 ways

Fibrinolytic drugs may be used to break up the embolus, but most are cholesterol or calcium, which do not respond.

In arteritic CRAO due to giant cell arteritis high dose systemic steroids prescribed to prevent fellow eye/other vessels from being affected.