DIS - Basic Pathology: Vascular II - Week 9 Flashcards
Where does CRVO tend to occur and at what age?
Usually behind the lamina cribrosa, typically >65yoa
List the three types of CRAO blockages that can occur.
Cholesterol
Fibrin platelets
Calcium
Where do cholesterol emboli tend to occur? Do they generally cause occlusion?
At bifurcations
Rarely cause occlusion
What is the loss of vision like with CRAO? Is pain involved? Is it acute or chronic?
Acute, severe, painless
What may CRAO precede (2)?
TIA / amaurosis fugax
Is RAPD present with CRAO?
Yes
What magnitude of vision lodd can occur with CRAO?
NLP
What is the ERG like with CRAO?
Normal a wave
Diminished/absent b wave
List 6 fundus findings you would expect with CRAO.
Superficial retinal whitening
Cherry red macula spot
Attenuated retinal arterioles
Retinal embolus visible
Segmentation of arterial blood column
Possible sector of normal retinal colour if ciliomacular artery is present
What happens to retinal filling in angiography with CRAO?
Delay
List two differential diagnoses for CRAO.
Tay sachs disease
Ophthalmic artery occlusion
How should CRAO be referred (2)? How urgent is it?
Ophthalmologist - urgent if <48h
GP - evaluation of risk factors
List 5 possible interventions for CRAO. Explain each.
Ocular massage - gonio lens 10s on, 5s off
Isosorbide - dilates peripheral vessels
Diamox - reduces IOP
Paracentesis - rapid IOP lowering
IV streptokinase - dissolves fibrin clots
What is the prognosis of CRAO like? What about if it is caused by calcific emboli or GCA?
Poor, especially with calcific thrombi or GCA
List four things that happen over the weeks with CRAO.
Retinal whitening fades
Attenuated arteries remain
Optic atrophy
Risk of NVG
What is the mebolus size like in BRAO compared to CRAO? Where does the blockage usually occur? At what age typically?
Smaller
Usually at arterial bifurcation
-further up the arterial tree
-typically >65yoa
Is RAPD present or absent with BRAO?
May or may not be
-will be if retinal loss is large enough
What is the prognosis of BRAO like (2)?
Poor unless the embolus dislodges
List four signs of BRAO.
Retinal clouding
Embolus (look at other branches)
Attenuated arteries
Segmentation
List three differential diagnoses for retinal whitening due to inflammation (BRAO).
Lymphoma
Toxoplasmosis chorioretinitis
CMV retinitis
List a differential diagnosis for non-inflammatory retinal whitening (BRAO).
Medullated nerve fibres
How should BRAO be managed?
As per CRAO
What is meant by combined CRAO/CRVO? How common is it? What is vision loss like and what onset?
Blockage of both the CRA and CRV
Very rare presentation
Very poor vision with acute onset
How does the retina appear with combined CRAO/CRVO (4)?
Retinal whitening
Extensive retinal haemorrhage
Macular oedema
Dilated vessels
What is the management like for combined CRAO/CRVO and what is there a risk of?
As per CRAO with systemic workup as per CRAO
Risk of NVG
What is ocular ischaemic syndrome?
Marked carotid/ophthalmic artery obstruction
What is required for ocular ischaemic syndrome? Describe in terms of percentages (2).
Requires significant decrease in flow/arterial hypoperfusion
-no symptoms without 70% reduction
what percentage obstruction to the carotid/ophthalmic artery will cause a 50% decrease in CRA flow?
90%
List four causes/associations of ocular ischaemic syndrome.
Atherosclerosis
Giant cell arteritis
Diabetes
Previous stroke/CVA
What happens to vision with ocular ischaemic syndrome? What happens with light exposure?
There is a slow decline
Slow recovery in vision after light exposure