2: Diabetic and HTN Retinopathy Flashcards
What is diabetic retinopathy
progressive destruction of retinal microvasculature caused by chronic hyperglycaemia
What is the main cause of blindness in 25-65 year-olds
diabetic retinopathy
What are 3 risk factors for diabetic retinopathy
Age
Uncontrolled diabetes
HTN
what are 3 common symptoms of diabetic retinopathy
Blurred vision
Floaters
Sudden visual-loss
How can diabetic retinopathy be classified
Proliferative and Non-Proliferative diabetic retinopathy
How is non-proliferative diabetic retinopathy divided
Mild
Moderate
Sevre
What is 1 feature of mild non-proliferative diabetic retinopathy
1 or more micro aneurysms
What are the 6 features for moderate non-proliferative diabetic retinopathy
- Micro-aneurysms
- Blot haemorrhage (Flame-shaped haemorrhage)
- Hard exudates
- Cotton wool spots
- Venous loops
- Intra-retinal microvascular abnormality
What are the 3 features for severe non-proliferative diabetic retinopathy
- Micro-aneurysms in >4
quadrants - Venous bleed in >2 quadrants
- IRMA in one-quadrant
What is a more common type of retinopathy in T1DM
Proliferative diabetic retinopathy
What is risk of proliferative diabetic retinopathy
Neovascularisation increases risk of vitreous haemorrhage
What are the earliest sign of diabetic retinopathy
Micro-aneurysms
What are micro aneurysms
Dilations of capillary
How do micro aneurysms appear on fundoscopy
Red dots - often in clusters
What is a blot (or flame-shaped) haemorrhage also known as
Intra-retinal haemorrhage
What decides if an intra-retinal haemorrhage is called a blot or flame-shaped haemorrhage
Retinal depth
What is a flame-shaped haemorrhage
Superficial layer of retina
What is a blot haemorrhage
Deeper layer of retina
How do hard exudates appear on retinopathy
yellow patches
What causes hard exudates
extracellular lipids leaking from defective capillaries
Where are hard exudates more commonly found
by the macula
Explain venous loops
dilation and duplication of veins occurs as retina undergoes ischaemia
what is intra-retinal microvascular abnormalities (IRMA)
areas of new capillary formation that occurs secondary to retinal ischaemia
Explain neovascularisation
As retinal ischaemia occurs - new blood vessels arise
How does neovascularisation present on fundoscopy
‘tufts’
How can progression of diabetic retinopathy be classified
- Diabetes without retinopathy
- Non-proliferative DR
- Proliferative DR
Explain diabetes without retinopathy
Hyperglycaemia causes damage to pericytes (cells responsible for surrounding blood vessels to control flow)
What does damage to pericytes in non-proliferative DR cause
- Damage to pericytes causes weakening of capillaries leading to micro aneurysms
- Damage to pericytes increases permeability of capillaries enabling lipids to leak into retinal tissue causing hard exudates
When does non-proliferative DR often onset after diagnosis
15-20 years
Explain proliferative DR
- Microvascular damage thus far causes retinal ischaemia
- To compensate, retina releases VEGF
- This increases proliferation of vessels
- These vessels are insufficient to supply the retina and can lead to vitreous haemorrhage
What other eye condition does diabetes increase the risk of
cataracts
Why does diabetes increase the risk of cataracts
glucose is absorbed by the lens and converted to sorbitol where it precipitates
If individuals have maculopathy, non-proliferative DR or proliferative DR how soon should they be reviewed by opthalmology
Urgently
Explain screening for diabetes
Individuals are screened at diagnosis and annually thereafter
How is screening for diabetic retinopathy performed
Dilated fundus photography
Why is dilated fundus photography performed
to identify neovascularisation early to enable photocoagulation laser treatment
When should individuals be referred to surgeons from diabetic retinopathy screening
if pre-proliferative retinopathy, proliferative, macuolopathy
On diabetic eye-screening what is R0
No retinopathy
On diabetic eye-screening what is R1
Mild non-proliferative retinopathy
On diabetic eye-screening what is R2
Severe non-proliferative retinopathy
On diabetic eye-screening what is R3
Proliferative retinopathy
On diabetic eye-screening what is M0
No maculopathy
On diabetic eye-screening what is M1
Maculopathy
What is the treatment for diabetic retinopathy
Laser photocoagulation treatment
What can be used in addition to laser photocoagulation treatment to treat diabetic retinopathy
Intra-vitreal triamcinolone or anti-VEGF
What should also be controlled in diabetic retinopathy
BP: aim for less than 130/80
What BP defines HTN
> 140/90
What BP defines malignant HTN
> 220/120
What classification is used for HTN retinopathy
Keith-Wegner
Of the Keith-Wegner classification, what stages are usually seen in chronic HTN
Stage 1 and 2
Of the Keith-Wegner classification, what stages are usually seen in malignant HTN
Stage 3 and 4
What are the 3 signs of stage I keith-wegner HTN retinopathy
- AV narrowing and increases tortuosity
- Increased light reflex
- Sclerosis - causing silver wiring
What is a sign of stage 2 ketih-wegner HTN retinopathy
AV nicking
What is a sign of stage 3 Keith wegner HTN retinopathy
Cotton wool spots
Flame-shaped haemorrhages
What is a sign of stage 4 Keith wegner HTN retinopathy
Papilloedema
How may malignant HTN present
Headache, eye pain, reduced visual acuity
What is the target BP if hypertensive retinopathy
<130/90
if a diabetic has proteinuria what is the target BP
<125/75
What visual conditions can HTN retinopathy pre-dispose to
- Accelerates diabetic retinopathy
- Retinal artery and vein occlusion
- Vitreous haemorrhage
- Papilloedema
