DIABETIC FOOT

Introduction

This is a serious burden for both the patient and physician. Once it occurs, it is very difficult to treat. Therefore prevention is the best option.

Prevalence and prognosis

1. 5-15% of Diabetics develop foot ulcers
2. 70% of healed Diabetic ulcer are likely to recur within 5 years
3. 85% of non traumatic lower limb amputations follow diabetic foot ulcers

Why do Diabetics sustain trauma to feet?

There are two main factors which make the diabetic patient more susceptible for trauma

1. Extrinsic
I. Poor vision
II. Falls due to joint immobility
III. strokes
IV. Edema due to Cardiac causes

2. Intrinsic
I. Neuropathy
II. Arterial Disease
III. Abnormal tissue response to trauma and sepsis

I) Neuropathy

a. Sensory – loss of pressure, pain, temperature and joint sense. i.e. removes warning signals
b. Motor – weakness and atrophy of intrinsic muscles of foot, hence altered foot structure and leading to deformity and altered biomechanics
c. Autonomic – AV shunting affects maintenance of skin integrity and vascular tone. i.e. warm, dry, fissured foot



What is Charcot foot?

This is the extreme end of diabetic foot disease. This occurs due to the long standing neuropathy. Other factors that contribute to charcot foot are as follows;

a) Long duration Diabetic neuropathy
b) Hyperaemic response
c) Osteopenia
d) Local fractures
e) Inflammatory response
f) Proprioception – Deformity
g) 0.2% of Diabetics





II) Arterial Disease


There are two types;

A. Macrovascular
B. Microvascular

A) Macrovascular Disease

Atherosclerosis is the main form of macrovascular disease affecting the foot and it increases the risk 4 to 20 times than in non-diabetics. In atherosclerosis;


 Systemic disease Coronaries, Cerebrals
 Calcification Unreliable AB index
 Collateral disease Poor reserve
 Angiography often foot vessels preserved

B) Microvascular Disease
1. Early onset of micro-vascular dysfunction
2. Affects arterioles an capillaries of several organs
3. Basement membrane thickening may impair oxygen diffusion
4. Reduced tissue response to sepsis

Wound healing is affected by...

 Growth factors deficiency
 Impaired fibroblast response
 Abnormalities of Extracellular matrix
 Neuroinflammatory response
 Hyperaemic response
 Thermoregulatory response

Diabetic foot Infections
 Cell mediated immunity depressed
 Phagocytic function of multinuclear leukocytes affected
 Leucocyte migration at microcirculatory level is affected
 Hyperglycaemia associated with mycotic infections could contribute
Painless collection of pus
 Tracking of pus along tendon sheaths
 Staphylococcus aureus is common
 Foot compartments

CLINICAL ASSESSMENT OF A DIABETIC FOOT

A) General

 Glycaemic control
 Smoking
 Renal disease
 Poor social circumstance

B) Extent of Neuropathy

 Vibration sense – using tuning fork
 Discriminating touch – 10g monofilament Nylon
 Ankle jerks


C) Extent of Ischaemia
 Pulse examination – Aortoiliac and FemPop bruits
 Skin color, Temperature
 ABPI
 X ray medial calcinosis


D) Extent of Neuroischaemia and sepsis

Wargner 1-5 a Global Severity Score

1: Superficial ulceration limited to dermis
2: Ulceration down to fascia or bone without abscess or osteomyelitis
3: Deep ulcers with abscess or osteomyelitis
4: Localized gangrene confined to the toes or forefoot
5: Gangrene requiring immediate major (above ankle) amputation

Extent of Infection Is Due to..

 Walking on pus
 Tracking of pus along tendons
 Foot compartments
 Septicaemia