The Macrovascular Complication of Diabetes and The Diabetic Foot

Question 1

State the four main microvascular diseases

Answer 1

1. Ischaemic Heart Disease
2. Cerebrovascular Disease (occurs earlier than without diabetes; more common in 60+ age)
3. Peripheral Vascular Disease- (contributes to diabetic foot problems with neuropathy being the main cause)
4. Renal Artery Stenosis (may contribute to hypertension and renal failure)

Question 2

Diabetes increases risk of atheroma formation. Briefly outline sequences in progression of atherosclerosis

Answer 2

• Adhesion of monocytes to intact endothelium, followed by migration along a chemotactic gradient into the intima, where they become macrophages. (these events appear to be modulated by lipoproteins)
• Subendothelial macrophages accumulate cholesteryl ester and become the foam cells of the fatty streak.
• Smooth muscle cells proliferate in response to stimulation by mitogens.
• Later, intimal macrophages and smooth muscle cells also accumulate lipid
• Later, lipoproteins accumulate in the extracellular space forming and extracellular lipid core.
• Single or multiple lipid cores with fibrotic/calcified layers = fibroatheroma
• Surface defect/ haematoma/ thrombisis => complicate lesion

Question 3

Managing blood glucose alone does not decrease the risk of macrovascular disease. You need to manage multiple risk factors of macrovascular disease. Name them.

Answer 3

Modifiable:
Dyslipidaemia (high cholesterol- treated with statin)
High BP 
Smoking 
Diabetes

Non- modifiable: age, sex, birth weight, genes

Question 4

What is the Framingham risk score?

Answer 4

algorithm to estimate 10-year cardiovascular disease risk of an individual

Question 5

What is the major cause of morbidity and mortality in diabetes?

Answer 5

ischaemic heart disease

the mechanisms are similar with and without diabetes

Question 6

What is the most common site of ulcers on the foot?

Answer 6

Ball of the foot

Question 7

Describe and explain the process of foot ulceration

Answer 7

1) Motor neuropathy - imbalance in flexors and extensors => abnormal foot shape (flat foot) => increased pressure on ball and knuckles
2) Limited joint mobility - sugar bound Hb sticks to collagen in tendons and makes them less flexible
3) Autonomic neuropathy - causes abnormal blood flow in foot which increases pulse pressure, also reduces sweating which normally protects foot from minor disease
4) Trauma - because of the above
5) Sensory neuropathy - you don’t feel the trauma
6) Peripheral vascular disease - blocked arteries and abnormal blood flow; poor blood flow to area of injury means it can’t heal well
7) Reduced resistance to infection- due to high blood glucose - bacteria and yeast love this environment

Question 8

What are the three types of diabetic feet?

Answer 8

Neuropathic Foot
Ischaemic Foot
Neuro-ischaemic Foot (combination of symptoms of the above)

Question 9

Describe the neuropathic foot. Where is the most common site of ulceration in these feet?

Answer 9

• Numb
• Warm (because blood flow isn’t regulated properly)
• Dry
• Palpable foot pulses

Ulcers – at points of high-pressure loading

Question 10

Describe the ischaemic foot. Where is the most common site of ulceration in these feet?

Answer 10

• Cold
• Pulseless

Ulcers – at foot margins

Question 11

What is Charcot’s foot?

Answer 11

Charcot foot is a condition causing weakening of the bones in the foot that can occur in people peripheral neuropathy. The bones are weakened enough to fracture, and with continued walking, the foot eventually changes shape (abnormal shape predisposes them to ulcers due to the abnormal distribution of pressure)

Question 12

What can ulceration of the foot lead to?

Answer 12

Osteomyelitis (infection of bone)

Question 13

Describe how to assess the foot of a diabetic patient?

Answer 13

Appearance

Feel - (Hot/cold, Dry?)

Foot pulses (dorsalis pedis / posterior tibial pulse)

Neuropathy (vibration sensation, temperature, ankle jerk reflex, fine touch sensation)

Question 14

Describe the preventative management for diabetic foot

Answer 14

• Control diabetes
• inspect feet daily
• have feet measured when buying shoes
• buy shoes with laces and square toe box
• inspect inside of shoes for foreign objects
• attend chiropodist
• cut nails straight across
• care with heat
• never walk barefoot

Question 15

Describe the management of foot ulceration

Answer 15

Relief of pressure (bed rest, redistribution of pressure/total contact cast)

Antibiotics

Debridement

Revascularization (angioplasty,
arterial bypass surgery

Amputation