Retinal Pathiphysiology Flashcards
Define microangiopathy
Disease of the capillaries and changes with the vessels such as thickness and weakness leading to leakage
Explain pericytes and their functions
Pericytes are cells that encircle the endo cells of the vessel wall and they provide vascular stability and control endo proliferation
What happens when there’s a loss of pericytes?
There’s reduced vessel strength which leads to bulging of the vessel into the surrounding tissue which are microaneurysms.
There’s also an increase or endo cell proliferation which leads to uncontrollable growth of new endo cells
What are the signs of diabetic retinopathy?
Microaneurysms, cotton wool spots. +RAPD, disc oedema, Irma, reduced va, beading, looping
What is the first sign of diabetic retinopathy?
Microaneurysms
What are signs of diabetic retinopathy?
Microaneurysms, increased vascular permeability, capillary occulsion,
Explain why increased vascular permeability occurs in diabetic retinopathy?
With hyperglycaemic changes to blood flow, pericyte loss and microaneurysms lead to the breakdown of the blood retinal barrier
What happens when the blood retinal barrier breaks down?
The tight junctions become compromised leading to increase of harmful constituents into the tissue. The harmful things may be: RBC causing haemorrhages, PLASMA leading to oedema and LIPIDS leading to hard exudates
Explain capillary occlusion
The reduction in blood flow leads to reduced pressure leading to no perfusion of oxygenated blood leading to capillary occulsion.
Give some characteristics of capillary occulsion
Can’t see with opthalmoscopy, located in clusters near microaneurysms, areas of capillary closure located mid and far periphery, capillary closure associated with ischemia therefore can predict where neovasc can occur
