Micro and Macrovascular Complications Flashcards
What are microvascular and macrovascular complications?
Micro: Nephropathy, neuropathy, retinopathy
Macro: Cerebravascular disease, Ischaemic Heart Disease, Peripheral vascular disease
What is the relationship of risk with rising HbA1c?
Extent of hyperglycaemia (as judged by HbA1c) is strongly associated with the risk of developing microvascular complications. Target HbA1c to reduce risk of microvascular complications is 53mmol/L.
How does blood pressure contribute to risk?
Clear relationship between rising systolic BP and risk of MI and microvascular complications in people with T1DM and T2DM. Therefore, prevention of complications requires reduction in HbA1c and BP control.
What are 5 factors related to the development of microvascular complications?
- Duration of diabetes
- Smoking – endothelial dysfunction
- Genetic factors – some people develop complications despite reasonable glycaemic control
- Hyperlipidaemia
- Hyperglycaemic memory – inadequate glucose control early on can result in higher risk of complications LATER, even if HbA1c improved.
Describe the mechanism of damage
Hyperglycaemia and hyperlipidaemia lead to increased formation of mitochondrial superoxide free radicals in the endothelium. Leads to generation of glycated plasma proteins to form advanced glycation end products (AGEs). This leads to activation of inflammatory pathways. Endothelium then damaged leading to leaky capillaries and ischaemia.
Why is diabetic retinopathy screened for?
The early stages of retinopathy are all asymptomatic, therefore screening is needed. Aim of screening - to detect retinopathy EARLY when it can be treated before it causes visual disturbance / loss. Annual retinal screening in the UK for all diabetes patients.
What are the features of background retinopathy?
Hard exudates (cheese colour, lipid) Microaneurysms (“dots”) Blot haemorrhages
What are features of pre-proliferative retinopathy?
Cotton wool spots also called soft exudates. Haemorrhages. Represent retinal ischaemia.
What is a feature of proliferative retinopathy?
Visible new vessels
On disc or elsewhere in retina
What are features of maculopathy?
Hard exudates / oedema near the macula
Same disease as background, but happens to be near macula
This can threaten vision
What are general treatment principles for retinopathies and specific for background retinopathy?
General: Good HbA1c, BP control, lipid lowering, stop smoking
Specific: Annual surveillance
How is pre-proliferative ret., prolif ret and maculopathy treated?
Pre-prolif: Can lead to development of new vessels so early panretinal photocoagulation
Prolif: panretinal photocoagulation
Maculopathy:
Oedema: Anti-VEGF injections directly into the eye (VEGF: vascular endothelial growth factor)
Grid photocoagulation
What is panretinal photocoagulation?
Thermal burns created on the retina causing tissue coagulation and overall improving oxygenation, reducing the hypoxia induced by capillary non-perfusion.
Why is diabetic nephropathy important?
Associated with progression to end-stage renal failure requiring haemodialysis. Is a healthcare burden and associated with increased risk of cardiovascular events.
How is nephropathy diagnosed?
Progressive proteinuria (urine albumin:creatinine ratio - ACR)
Increased blood pressure
Deranged renal function (eGFR)
Advanced: peripheral oedema
Microalbuminuria of >2.5mg/mmol is diagnosis
Proteinuria = ACR > 30mg/mmol
Nephrotic Range > 3000mg/24hr