[9] Diabetic Retinopathy Flashcards

1
Q

What eye problems can be associated with diabetes mellitus (DM)?

A
  • Diabetic retinopathy (most common)
  • Cataracts
  • Rubeosis iridis and glaucoma
  • Oculomotor nerve palsies
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2
Q

What is diabetic retinopathy?

A

A chronic progressive, potentially sight-threatening disease of the retinal microvasculature

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3
Q

What is diabetic retinopathy associated with?

A

Prolonged hyperglycaemia of DM and other diabetes-linked conditions such as hypertension

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4
Q

How is diabetic retinopathy classified?

A

Based on the ares of the retina affected and the degree of pathology seen on slit lamp examination

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5
Q

What are the two broad types of diabetic retinopathy?

A
  • Diabetic retinopathy

- Diabetic maculopathy (I think this is potentially a separate thing thats closely related but idk so lets roll with it)

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6
Q

What are the classifications of diabetic retinopathy (DR)?

A
  • Background (mild) non-proliferative DR
  • Moderate non-proliferative DR
  • Severe to very severe non-proliferative DR
  • Non-high risk proliferative DR
  • High-risk proliferative DR
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7
Q

What is background non-proliferative diabetic retinopathy?

A

1 microaneurysm seen on slit lamp examination on background of DM

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8
Q

What is moderate non-proliferative diabetic retinopathy?

A

Moderate amount of micro-aneurysms and intra-retinal haemorrhages with or without cotton wool spots, venous beading or other intra-retinal micro-vascular abnormalities

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9
Q

What is severe to very severe non-proliferative diabetic retinopathy?

A

Like moderate but more severe (obvs)

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10
Q

What is non-high risk proliferative diabetic retinopathy?

A

Where there are new vessels on the disc (or within 1 disc diameter) or elsewhere

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11
Q

What is high risk proliferative diabetic retinopathy?

A
  • Large new vessels on the disc or elsewhere
  • Potentially pre-retinal haemorrhages
  • Potentially retinal detachment in advanced disease
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12
Q

What are the types of diabetic maculopathy?

A
  • Focal or diffuse macular oedema
  • Ischaemic maculopathy
  • Clinically significant macular oedema
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13
Q

What are the features of focal or diffuse macular oedema diabetic maculopathy?

A

What are the features of focal or diffuse macular oedema diabetic maculopathy?

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14
Q

What are the features of ischaemic diabetic maculopathy?

A
  • Clinically appear relatively normal
  • Visual acuity is dropped
  • Ischaemia seen on fluorescein angiography
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15
Q

What are the features of clinically significant macular oedema?

A
  • Thickening of the retina

- Hard exudates around the fovea or above a certain size

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16
Q

What causes diabetic retinopathy?

A

Diabetes mellitus

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17
Q

What is the mechanism behind diabetic retinopathy?

A

Microvascular occlusions cause retinal ischaemia leading to arteriovenous shunting, neovascularisation, intra retinal haemorrhages and oedema

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18
Q

What are the characteristic features that can be seen at different stages of diabetic retinopathy?

A
  • Micro-aneurysms
  • Hard exudates
  • Haemorrhages
  • Cotton wool spots
  • Neovascularisation
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19
Q

What are micro-aneurysms in diabetic retinopathy?

A

Physical weakening of the capillary walls that predispose them to leakages

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20
Q

What are hard exudates in diabetic retinopathy?

A

Precipitates of lipoproteins/other proteins leaking from the retinal blood vessels

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21
Q

What are the haemorrhages seen in diabetic retinopathy?

A

Rupturing of weakened capillaries, appearing as small dots/larger blots or ‘flame’ haemorrhages that track along nerve-fibre bundles in superficial retinal layers

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22
Q

What are cotton wool spots seen in diabetic retinopathy?

A

Build up of axonal debris due to poor axonal metabolism in the margins of ischaemic infarcts

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23
Q

What is neovascularisation in diabetic retinopathy?

A

An attempt by residual healthy retina to revascularise hypoxic retinal tissue

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24
Q

What is progression of diabetic retinopathy mainly associated with?

A

Severity and length of hyperglycaemia

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25
Q

What are some other risk factors that influence onset and progression of diabetic retinopathy?

A
  • Hypertension
  • Other cardiovascular risk factors
  • Pregnancy
  • Minority ethnic community
  • Intraocular surgery
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26
Q

What are some excellent predictors of the presence of diabetic retinopathy?

A
  • Renal disease evidenced by proteinuria and elevated serum urea/creatinine
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27
Q

When should eye screening be performed in patients with diabetes?

A

At or around the time of diagnosis and then repeated annually

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28
Q

How is diabetic retinopathy screening conducted?

A

Via photographing the dilated retina

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29
Q

When should standard (4 week) referral to an ophthalmologist be made following diabetic retinopathy screening?

A
  • Referable maculopathy
  • Referable pre-proliferative retinopathy
  • Any large, sudden drop in visual acuity
30
Q

When should an urgent referral to an ophthalmologist be made following diabetic retinopathy screening?

A

When there is new vessel formation

31
Q

When should an emergency referral to an ophthalmologist be made following diabetic retinopathy screening?

A
  • Sudden loss of vision
  • Rubeosis iridis
  • Pre-retinal or vitreous haemorrhage
  • Retinal detachment
32
Q

Do all patients present with major symptoms in diabetic retinopathy?

A

No

33
Q

If patients with diabetic retinopathy present with symptoms what can they include?

A
  • Painless reduction of central vision
  • Dark, painless floaters that may resolve over several days
  • Painless visual loss
34
Q

What are floaters in diabetic retinopathy associated with?

A

Haemorrhages

35
Q

When may a patient with diabetic retinopathy get painless visual loss?

A

If haemorrhage obscures the vitreous

36
Q

Is the severity of symptoms in diabetic retinopathy always in correlation with the threat of the disease to sight?

A

No

37
Q

If assessing without a slit lamp, what steps should be taken when examining a patient for diabetic retinopathy?

A
  • Check acuity
  • Check red reflex
  • Assess each arterial branch from the optic disc outwards
  • End with assessing the macula
38
Q

What may be seen when checking the red reflex of a patient with diabetic retinopathy?

A

Spots suggestive of vitreous haemorrhage

39
Q

When assessing blood vessels in diabetic retinopathy what should be noted?

A
  • Little red dots (dot haemorrhages or small aneurysms)
  • Irregular notching (venous beading)
  • New vessels
40
Q

How can new vessels in the retina be identified in diabetic retinopathy?

A

Tend to be thinner and more disorganised than pre-existing vessels

41
Q

What else (extra-vascular signs) may be noted when following along the blood vessels in diabetic retinopathy?

A
  • Hard exudates

- Cotton wool spots

42
Q

How do hard exudates appear in diabetic retinopathy?

A

Creamy/yellow lesions often in clusters

43
Q

How do cotton wool spots appear in diabetic retinopathy?

A

Pale lesions with poorly defined edges

44
Q

What is the gold standard for diagnosing diabetic retinopathy?

A

Dilated retinal photography with accompanying ophthalmoscopy

45
Q

When may further investigation be required in diabetic retinopathy?

A

To refine the diagnosis and plan management

46
Q

What further investigations can be used in diabetic retinopathy?

A
  • Optical coherence tomography

- Fluorescein angiography

47
Q

What are the differentials for diabetic retinopathy?

A
  • Ocular ischaemic syndrome
  • Radiation therapy
  • Retinal venous occlusion
  • Hypertension
48
Q

What is involved in primary prevention of diabetic retinopathy?

A
  • Glycaemic control
  • Blood pressure control
  • Lipid control
  • Healthy diet
  • Exercise
  • Smoking cessation
49
Q

What is the aimed for HbA1c in patients with diabetes to try and prevent diabetic retinopathy?

A

<7%

50
Q

What is optimal glycaemic control associated with in terms of diabetic retinopathy?

A

Improved long-term outcomes and delayed progression

51
Q

What blood pressure should be aimed for in patients to prevent diabetic retinopathy?

A

≤140/80mmHg

52
Q

What does good blood pressure control do in relation to diabetic retinopathy?

A

Reduces progression

53
Q

What does lipid control do in relation to diabetic retinopathy?

A

Reduces the risk of progression, particularly macular oedema and exudation

54
Q

Do all patients with diabetic retinopathy require treatment?

A

No, most do not

55
Q

What options are available for treating diabetic retinopathy?

A
  • Laser treatment (laser photocoagulation)
  • Intravitreal steroids
  • Surgery
56
Q

What is the aim of laser photocoagulation in treating diabetic retinopathy?

A

To induce regression of new blood vessels and reduce central macular thickening

57
Q

How is laser photocoagulation thought to work?

A

Reduces the release of vasoproliferative mediators by hypoxic retinal vessels and allows easier direct diffusion of oxygen from the choroid blood supply

58
Q

How can laser photocoagulation be targeted?

A
  • Can target specific areas (focal)

- Can target entire retinal periphery (panretinal)

59
Q

What does the choice of the area targeted by laser photocoagulation depend on?

A

The nature of the diabetic retinopathy

60
Q

What type of diabetic retinopathy is treated with panretinal laser treatment?

A

Retinopathy

61
Q

What type of diabetic retinopathy is treated with focal laser treatment?

A

Macular oedema

62
Q

How is laser photocoagulation therapy carried out?

A

In a clinic on an outpatient basis

63
Q

How can areas of laser treatment for diabetic retinopathy be identified at a later date?

A

As well-demarcated pale spots with dark brown centres

64
Q

What are the complications of focal laser photocoagulation?

A
  • Impaired central vision
  • Paracentral scotoma
  • Choroidal neovascularisation
65
Q

What are the complications of panretinal laser photocoagulation?

A
  • Constriction of visual field
  • Nocturnal diminution of vision
  • Worsening macular oedema
  • Ocular pain
66
Q

What intravitreal steroid can be given as a primary or adjunctive therapy for diabetic retinopathy?

A

Intravitreal triamcinolone

67
Q

Over what period is intravitreal steroid therapy more effective than laser photocoagulation at treating diabetic retinopathy?

A

The first 2 years

68
Q

In what way is laser photocoagulation better than intravitreal steroids at treating diabetic retinopathy?

A

It provides better visual acuity and less maculopathy after 2 years

69
Q

What are the complications of intravitreal steroids in diabetic retinopathy?

A
  • Cataract formation

- Raised intraocular pressure

70
Q

What is the main complication of diabetic retinopathy?

A

Visual loss

71
Q

What is visual loss in diabetic retinopathy often secondary to?

A
  • Macular oedema
  • Macular ischaemia
  • Vitreous haemorrhage
  • Tractional retinal detachment