The diabetic foot

Clinical features:

Diabetics have a tendency to develop, often quite suddenly, severe ischaemia and infection in the feet which progresses to rapid tissue necrosis and amputation. There are 4 reasons for this:

• Vascular disease
• Sensory neuropathy
• Autonomic neuropathy
• Motor neuropathy

Vascular disease:

• In diabetics, this develops earlier in life and tends to be more extensive and distal
• The clinical features are similar to non-diabetic vascular disease except that a palpable popliteal pulse is more frequently present, due to the more distal distribution of the disease (particularly affecting the tibial vessels)

Sensory neuropathy:

• Reduces or abolishes protective reactions to minor injury and to symptoms of infection or ischaemia

Autonomic neuropathy:

• Causes a lack of sweating and the development of dry, fissured skin which permits entry of bacteria

Motor neuropathy:

Results in:

• Wasting and weakness of the small muscles
• Loss of the longitudinal and transverse arches of the foot
• Development of abnormal pressure areas, such as over the metatarsal heads

Management:

• Tissue loss is neuropathic or ischaemic, or more commonly a combination of both (neuroischaemic)

The principles of management are:

• Best medical care for the diabetes
• Wide debridement of devitalised tissue
• Drainage of pus
• Revascularisation (if ischaemia is present)