Microvascular + Macrovascular complications of diabetes

Question 1

Diabetic retinopathy: pathophysiology

Answer 1

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.

Question 2

Damage to the blood vessel walls can lead to:

Answer 2

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.

Question 3

Damage to nerve fibres in the retina causes?

Answer 3

fluffy white patches to form on the retina called cotton wool spots.

Question 4

Intraretinal microvascular abnormalities (IMRA) is where?

Answer 4

there are dilated and tortuous capillaries in the retina. These can act as a shunt between the arterial and venous vessels in the retina.

Question 5

Neovascularisation is when?

Answer 5

growth factors are released in the retina causing the development of new blood vessels.

Question 6

Classification of diabetic retinopathy:

Answer 6

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.

Question 7

Non-proliferative Diabetic Retinopathy

Answer 7

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

Question 8

Proliferative Diabetic Retinopathy includes:

Answer 8

Neovascularisation

Vitreous haemorrhage

Question 9

Diabetic Maculopathy types

Answer 9

Macular oedema

Ischaemic maculopathy

Question 10

Complications of Diabetic Retinopathy

Answer 10

Retinal detachment
Vitreous haemorrhage (bleeding in to the vitreous humour)
Rebeosis iridis (new blood vessel formation in the iris)
Optic neuropathy
Cataracts

Question 11

Management of diabetic retinopathy

Answer 11

Laser photocoagulation

Anti-VEGF medications such as ranibizumab and bevacizumab

Vitreoretinal surgery (keyhole surgery on the eye) may be required in severe disease

Question 12

Prevention of Foot ulcers: DOs

Answer 12

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

Question 13

Prevention of Foot ulcers: Don’t

Answer 13

Use corn cures

Use hot water bottles

Walk barefoot

Cut corns/callosities

Treat foot problems yourself

Wear ill-fitting shoes

Cannulate diabetic patients feet

Question 14

Diabetic foot disease occurs secondary to two main factors:

Answer 14

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

Question 15

Presentations of diabetic foot disease

Answer 15

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

Question 16

All patients with diabetes should be screened for diabetic foot disease on at least an annual basis including:

Answer 16

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

Question 17

Low risk for diabetic foot disease

Answer 17

no risk factors except callus alone

Question 18

Moderate risk of diabetic foot disease

Answer 18

• deformity or
• neuropathy or
• non-critical limb ischaemia.

Question 19

High risk of diabetic foot disease

Answer 19

• 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.

Question 20

Microvascular complications of diabetes

Answer 20

Nephropathy (kidney disease, particularly glomerulosclerosis)

Diabetic retinopathy
Peripheral neuropathy

Question 21

Macrovascular complications of diabetes

Answer 21

• Coronary artery disease is a major cause of death in diabetics
• Peripheral ischaemia causes poor healing, ulcers and “diabetic foot”
• Stroke
• Hypertension

Question 22

Vascular disease: macrovascular complication

Answer 22

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)

Question 23

vascular risk control:

Answer 23

BP control is crucial for preventing macrovascular disease and decreasing mortality