The Diabetic Foot

Question 1

What is the prevalence of diabetic foot?

Answer 1

• Complications of diabetes that predispose to foot disease include – neuropathy (sensory, motor and autonomic) and peripheral vascular disease.

Prevalence diabetes – 2-3%

Prevalence of current/past foot ulcerations in diabetes – 5-7%.

• Risk of amputation is 60x higher in diabetes.
• 10% of NHS bed occupancy due to diabetes-related problems (50% of those with foot disease).

Testing sensory function can be done via a mono-filament – when the filament bends, 10g of pressure has been applied which should be felt by the patient

Question 2

Outline the pathway to foot ulceration

Answer 2

Sensory neuropathy – cannot feel monofilament – ulcers due to abnormal pressures.

Motor neuropathy – imbalance of extensors/flexors so foot is abnormal shape – ulcers due to abnormal pressures.

Limited join mobility – causes joint immobility and cannot put hands flat against each other.

Autonomic neuropathy – no sweating so skin dries out and you get ulcers.

Peripheral vascular disease – blood flow is compromised to the lower limbs.

Trauma – repeated or minor episodes.

Reduced resistance to infection.

Other – diabetic complications (e.g. retinopathy).

Question 3

What are the features of nueropathic foot?

Answer 3

numb
warm
dry
palpable foot pulses
ulcers at points of pressure

Question 4

What are the features of ischaemic foot?

Answer 4

cold
pulseless
ulcers at the foot margins

Question 5

What are the features of neuro-ischaemic foot?

Answer 5

numb
cold
dry
pulseless
ulcers at point of pressure AND foot margins.

Question 6

How is diabetic foot managed?

Answer 6

From a diabetes perspective, the following must be managed:

• Hyperglycaemia
• Hypertension
• Dyslipidaemia
• Stop smoking
• Education

Preventative management includes:

• Controlling diabetes
• Inspecting feet daily
• Have feet measured for shoes
• Buying shoes with laces and square toe box
• Attend chiropodist - Cut nails straight across
• Take care when feet will get hot
• Never walk barefoot

Management of foot ulceration:

• Relief of pressure – bed rest and redistribution of pressure
• Antibiotics – possibly long-term
• Debridement
• Re-vascularisation – angioplasty or arterial bypass surgery
• Amputation

Question 7

What is Charcot foot?

Answer 7

The Charcot foot is described as a “rocker bottom” foot

The bones are orientated in an abnormal way which is painful to non-diabetics (but not for diabetics due to sensory neuropathy)
- Deformity due to loss of join-position sense

The abnormal shape predisposes to ulcer formation

• The ulcers can then predispose to osteomyelitis
• Osteomyelitis = bone infection
• Charcot foot = destruction of joints

Question 8

How can you differentiate between osteomyelitis and active charcot foot?

Answer 8

osteomyelitis:
hot red foot with ulcer
forefoot - MTPs and IPs
hindfoot - calcaneus
x-ray normal first weeks
MRI - marrow oedema in forefoot and hindfoot near ulcer

active charcot :
hot red foot but no ulcer
midfoot - subarticular
x-ray normal first weeks
MRI - marrow oedema in midfoot subchondral