diabetic retinopathy Flashcards
type 1 diabetes Sx
cutely with diabetic ketoacidosis or subacutely with weight loss,
polyuria, polydipsia, and fatigue.
Type 2 diabetes Sx
incidental finding (may have long asymptomatic period); or symptoms of weight loss, polyuria, polydipsia, and fatigue; or complications.
diagnosis of diabetes
Venous fasting plasma glucose ≥7mmol/L.
• Oral glucose tolerance test with a 2h
value of >11.1mmol/L.
pathophysiology of diabetic retinopathy
Hyperglycaemia is thought to cause increased retinal blood flow and abnormal metabolism in the retinal vessel walls. This precipitates damage to endothelial cells and pericytes
pathophysiology of exudates and microaneurysms and new vessels
Endothelial dysfunction leads to increased vascular permeability which causes the characteristic exudates seen on fundoscopy.
Pericyte dysfunction predisposes to the formation of microaneurysms.
Neovasculization is thought to be caused by the production of growth factors in response to retinal ischaemia
classification of non-proliferative diabetic retinopathy
Mild NPDR
1 or more microaneurysm
Moderate NPDR microaneurysms blot haemorrhages hard exudates cotton wool spots, venous beading/looping and intraretinal microvascular abnormalities (IRMA) less severe than in severe NPDR
Severe NPDR
blot haemorrhages and microaneurysms in 4 quadrants
venous beading in at least 2 quadrants
IRMA in at least 1 quadrant
proliferative retinopathy
retinal neovascularisation - may lead to vitrous haemorrhage
fibrous tissue forming anterior to retinal disc
more common in Type I DM, 50% blind in 5 years
maculopathy ?
based on location rather than severity, anything is potentially serious
hard exudates and other ‘background’ changes on macula
check visual acuity
more common in Type II DM
what Ix can differentiate between microaneurysms and intraretinal haemorrhages
fluorescein angiography
diabetic eye condx
glaucoma cataracts vascular - CAO CN palsies retinopathy
risk factors for progression of DR
duration of DM hyperglycaemia HTN hyperlipidaemia nephropathy pregnancy smoking
background retinopathy
Microaneurysms (dots), haemorrhages (blots), and hard exudates (lipid deposits). Refer if near the macula, e.g. for intravitreal triamcinolone. DOTS BLOTS AND DEPOTS (in lecture says cotton wool and deposits are background)
pre proliferative retinopathy
Cotton-wool spots (e.g. infarcts), haemorrhages, venous beading. These are signs of retinal ischaemia.
IRMA
Refer to a specialist.
proliferative retinopathy
New vessels form. Needs urgent referral. NEW VESSELS OF OPTIC DISC, FLORID
rubeosis iridis - new formed vessles on iris
Primary Tx for retinopathy
glycaemia control
BP
lipid lowering
