Diabetic Retinopathy: Pathogenesis and clinical findings
Authors: Graeme Prosperi-Porta Lucy Yang Reviewers: Stephanie Cote Usama Malik Mao Ding Johnathan Wong* * MD at time of publication
Family history of T1DM
Genetics: (DR3, DR4, DQ non-asp genes)
Ethnicity: White youth, African American, Hispanic, Asian-Pacific Islanders, and American Indigenous
Type 1 Diabetes Mellitus (T1DM) (see Diabetes Mellitus, Type I for pathogenesis)
Type 2 Diabetes Mellitus (T2DM) (see Diabetes Mellitus, Type II for pathogenesis)
Polycystic Ovarian Syndrome
Family history of T2DM
History of Gestational Diabetes
↑ Body Mass Index
↑ Age
Ethnicity: Indigenous Americans, African American, Hispanic
Poor glycemic control
Chronic high blood sugaràinflammatory response
↑ cytokines and growth factors including vascular endothelial growth factor (VEGF)
Vascular permeability Retinal neovascularization
Vascular endothelial dysfunction: basement membrane thickening, vascular cell death, vascular occlusion from platelet aggregation
Retinal hypoxia
Outpouchings of the weakened capillary walls or endothelial buds attempting to re-vascularize the ischemic retina
Weakened blood-retinal barrier (BRB) allows for rupture into the deeper retinal layers
Lipid deposits with sharp margins due to lipoproteins & other proteins leaking through the damaged blood-retinal barrier
Nerve fiber layer infarcts from occlusions of the precapillary arterioles
Retinal hemorrhages occur in the more superficial nerve layer
Focal areas of saccular venous bulges due to significant retinal ischemia & endothelial wall weakening and damage
Diabetic Retinopathy (DR)
A complication of diabetes due to chronic hyperglycemia resulting in abnormal permeability and ischemia of retinal vessels
Micro-aneurysms
Dot/blot hemorrhages Hard exudates (yellow
opaque solids on retina)
Cotton-wool spots (cloudy translucent patches on retina)
Flame hemorrhages
(multiple opaque red patches)
Venous beading (veins with areas of narrowing forming bead-like segments)
Traction retinal detachment
Bleeding into the vitreous humor
Pericyte death, breakdown of endothelial tight junctions & basement membrane thickening damages blood-retinal barrier
Damaged blood- retinal border leaks fluid into the retinal tissues
Macular edema
(swelling of macula)
Mild Non-proliferative DR
Moderate Non-proliferative DR
Severe Non-proliferative DR
Proliferative DR
Presence of neovascularization
Localized retinal ischemia causes upregulation of vascular endothelial growth factor causing fine, irregular & easily friable neovascularization in the disc, macula, and/or retina
Neovascularization
(fine loop networks of new blood vessels)
Neovascular membranes in vitreous gel form vitreoretinal adhesions and contract
Fragile vessels extending into the vitreous humor
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published June 28, 2017, updated May 18, 2023 on www.thecalgaryguide.com