Microvascular + Macrovascular complications of diabetes Flashcards
Diabetic retinopathy: pathophysiology
Hyperglycaemia leads to damage to the retinal small vessels and endothelial cells. Increased vascular permeability leads to leakage from the blood vessels, blot haemorrhages and the formation of hard exudates. Hard exudates are yellow/white deposits of lipids in the retina.
Damage to the blood vessel walls can lead to:
microaneurysms and venous beading. Microaneurysms are where weakness in the wall causes small bulges. Venous beading is where the walls of the veins are no longer straight and parallel and look more like a string of beads or sausages.
Damage to nerve fibres in the retina causes?
fluffy white patches to form on the retina called cotton wool spots.
Intraretinal microvascular abnormalities (IMRA) is where?
there are dilated and tortuous capillaries in the retina. These can act as a shunt between the arterial and venous vessels in the retina.
Neovascularisation is when?
growth factors are released in the retina causing the development of new blood vessels.
Classification of diabetic retinopathy:
non-proliferative and proliferative depending on whether new blood vessels have developed. Non-proliferative is often called background or pre-proliferative retinopathy as it can develop in to proliferative retinopathy.
A condition called diabetic maculopathy also exists separate from non-proliferative and proliferative diabetic retinopathy.
These conditions are classified based on the findings on fundus examination.
Non-proliferative Diabetic Retinopathy
Mild: microaneurysms
Moderate: microaneurysms, blot haemorhages, hard exudates, cotton wool spots and venous beading
Severe: blot haemorrhages plus microaneurysms in 4 quadrants, venous beading in 2 quadrates, intraretinal microvascular abnormality (IMRA) in any quadrant
Proliferative Diabetic Retinopathy includes:
Neovascularisation
Vitreous haemorrhage
Diabetic Maculopathy types
Macular oedema
Ischaemic maculopathy
Complications of Diabetic Retinopathy
Retinal detachment
Vitreous haemorrhage (bleeding in to the vitreous humour)
Rebeosis iridis (new blood vessel formation in the iris)
Optic neuropathy
Cataracts
Management of diabetic retinopathy
Laser photocoagulation
Anti-VEGF medications such as ranibizumab and bevacizumab
Vitreoretinal surgery (keyhole surgery on the eye) may be required in severe disease
Prevention of Foot ulcers: DOs
Wash feet daily
check feet daily
seek urgent treatment of problems
see a podiatrist or other diabetes healthcare profressional regularly
wear sensible shoes and socks
Prevention of Foot ulcers: Don’t
Use corn cures
Use hot water bottles
Walk barefoot
Cut corns/callosities
Treat foot problems yourself
Wear ill-fitting shoes
Cannulate diabetic patients feet
Diabetic foot disease occurs secondary to two main factors:
Neuropathy: resulting in loss of protective sensation (e.g. not noticing a stone in the shoe), Charcot’s arthropathy, dry skin
Peripheral arterial disease: diabetes is a risk factor for both macro and microvascular ischaemia
Presentations of diabetic foot disease
neuropathy: loss of sensation
ischaemia: absent foot pulses, reduced ankle-brachial pressure index (ABPI), intermittent claudication
complications: calluses, ulceration, Charcot’s arthropathy, cellulitis, osteomyelitis, gangrene
All patients with diabetes should be screened for diabetic foot disease on at least an annual basis including:
screening for ischaemia: done by palpating for both the dorsalis pedis pulse and posterial tibial artery pulse
screening for neuropathy: a 10 g monofilament is used on various parts of the sole of the foot
Low risk for diabetic foot disease
no risk factors except callus alone
Moderate risk of diabetic foot disease
- deformity or
- neuropathy or
- non-critical limb ischaemia.
High risk of diabetic foot disease
- previous ulceration or
- previous amputation or
- on renal replacement therapy or
- neuropathy and non-critical limb ischaemia together or
- neuropathy in combination with callus and/or deformity or
- non-critical limb ischaemia in combination with callus and/or deformity.
Microvascular complications of diabetes
Nephropathy (kidney disease, particularly glomerulosclerosis)
Diabetic retinopathy
Peripheral neuropathy
Macrovascular complications of diabetes
- Coronary artery disease is a major cause of death in diabetics
- Peripheral ischaemia causes poor healing, ulcers and “diabetic foot”
- Stroke
- Hypertension
Vascular disease: macrovascular complication
Chief cause of death. MI is 4 fold commoner in DM and is more likely to be ‘silent’.
Stroke is twice as common
Women are at high risk
Suggest a statin (eg atorvastatin 20mg nocte) for all, even if no overt IDH, vascular disease, or microalbuminuria
Aspirin 75mg reduces vascular events (in secondary prevention)
vascular risk control:
BP control is crucial for preventing macrovascular disease and decreasing mortality
