Microvascular Complications of Diabetes - Retinopathy

Question 1

diabetic retinopathy

Answer 1

damage to the retina and iris caused by diabetes which can lead to blindness

is associated with several complications (cataract, glaucoma, acute hyperglycaemia)

Question 2

cataracts

Answer 2

the denuration of protein and other components of the lens of the eye render it opaque

develops early in people with diabetes, and can be reversed with return to normoglycaemia

Question 3

glaucoma

Answer 3

the increase in fluid pressure in the eye lead to optic nerve damage

2x more likely in DM

Question 4

acute hyperglycaemia

Answer 4

visual blurring

• acute short sightedness is a possible acute presentation of DM
• reversible once normoglycaemia established

Question 5

symptoms of diabetic retinopathy

Answer 5

tend to be mild initally (eg visual burring or dark spots/floaters)

however, can be more serious (eg sudden onset of blindness)

Question 6

what are the stages defined by

Answer 6

pathology, rather than symptoms/clinical presentation

Question 7

diabetes without retinopathy

Answer 7

underlying hyperglycaemia causes damages to pericytes in the retina that are important in regulating blood flow. damage to them is caused by an inability to properly metabolise glucose - osmotic damage

Question 8

what are the signs of diabetes without retinopathy

Answer 8

likely present in most individuals who have had diabetes for a few years, not detectable on eye exam

no signs of retinopathy, but underlying damage

Question 9

non proliferative retinopathy

Answer 9

damage to retinal pericytes causes weakening of capillary wall and increased blood flow - formation of microaneurysms

- these appear as red dots and are typically the first clinical sign

damage to pericytes also increases vascular permeability (leaky capillaries), this means proteins and lipids can leak out into retinal tissue and are trapped - form hard exudates (yellow/white flecks on retina)

Question 10

at what stage does non-proliferative retinopathy usually occur

Answer 10

25 years after DM diagnosis

Question 11

is non proliferative retinopathy symptomatic

Answer 11

may or may not be

Question 12

proliferative retinopathy

Answer 12

characterised by vascular proliferation within the retina - this is the retina trying to compensate for ischaemia due to retinal damage. produces a groth factor (VEGF) which produces new blood vessels

however, these are abnormal and do not compensate for ischaemia

Question 13

symptoms of proliferative retinopathy

Answer 13

uncommonly asymptomatic

usually patients at least have blurry vision and floaters

Question 14

prognosis

Answer 14

once diabetic retinopathy is proliferative, prognosis is poor and unpredictable

can result in vision threatening complications

Question 15

maculopathy

Answer 15

damage to the macula

suspected when acuity (clarity of vision) is decreased

Question 16

macula

Answer 16

surrounds the fovea - portion of retina with highest density of cones (colour and high resolution image)

Question 17

when would one refer maculopathy

Answer 17

lesions (specified below) are within a radius of <1 disc diameter of the centre of the fovea

• blot haemorrhages
• hard exudates

Question 18

diabetic retinopathy treatment

Answer 18

laser

vitrectomy (remocal of vitreous gel from middle of eye)

anti-VEGF (growth factor) injections

Question 19

Answer 19

laser burns on retina

Question 20

background retinopathy criteria

Answer 20

• at least 1 dot haemorrhage or microaneurysms with/out hard exudate
• cotton wool spot
• <4 blot haemorrhages
• review in one year

Question 21

moderate diabetic retinopathy criteria

Answer 21

• ≥4 haemorrhages
• rescreen in 6 months