19 - The Diabetic Foot

Question 1

What are the two main factors/complications of diabetes that lead to four disease?

Answer 1

neuropathy

peripheral vascular disease

Question 2

What is the most common cause of foot amputation in the UK?

Answer 2

the diabetic foot (duh)

Question 3

What test is used to see if someone has peripheral neuropathy?

Answer 3

Monofilament test

Question 4

What is the monofilament test for?

Answer 4

assessing the loss of protective sensation

Question 5

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

Answer 5

Ball of the foot

Question 6

Which nerve in the body is the most susceptible to nerve damage and why? How does this relate to the diabetic foot?

Answer 6

the sensory nerve in our big toe because it is the longest

Question 7

Give the order of of importance/pathway of causes of foot ulceration

Answer 7

1- sensory neuropathy
2- motor neuropathy
3- limited joint mobility
4- autonomic neuropathy
5- peripheral vascular disease
6- trauma
7- reduced resistance to infection
8- other diabetic complications e.g. retinopathy

Question 8

What three arms of neuropathy are involved in causing foot ulceration and how are they involved?

Answer 8

Motor – causes imbalance between extensors and long plantar flexors causing an abnormal shape of the foot. This means there will be increased pressure being applied on the ball of the foot and knuckles of the toes.
Sensory
Autonomic – can lead to abnormal blood flow (increase pulse pressure in the foot). It also reduces sweating, which normally protects the foot from minor disease.

Question 9

How can limited joint mobility be caused as a result of diabetes?

Answer 9

sugar binding to haemoglobin (HbA1c) can make tendons less flexible

Question 10

What are the three types of diabetic feet?

Answer 10

Neuropathic Foot
Ischaemic Foot
Neuro-ischaemic Foot

Question 11

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

Answer 11

Numb
Warm (because blood flow isn’t regulated properly)
Dry
Palpable foot pulses
Ulcers – at points of high-pressure loading

Question 12

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

Answer 12

Cold
Pulseless
Ulcers – at foot margins

Question 13

What is Charcot foot?

Answer 13

‘rocker bottom’ foot
The neuropathy leads to joint overuse and misuse
This leads to bones losing their normal articulations
The abnormal foot shape makes it at extreme risk of ulceration

Question 14

What is the most common cause of Charcot’s foot?

Answer 14

diabetes

Question 15

What can ulceration of the foot lead to?

Answer 15

Osteomyelitis

Question 16

Compare osteomyelitis and Charcot’s foot in what they are, how they would feel and how they would appear on MRI

Answer 16

Osteomyelitis: infection of bone
Charcot’s foot: destruction of joints

O: hot red foot with ulcer
Cf: hot red foot with no ulcer

MRI
O: marrow oedema in forefoot and hindfoot near ulcer
Cf: marrow oedema in midfoot subchondal