29th May 2025

Diabetic foot disease

Vascular and neurovascular damage associated with T2DM can lead to several problems in the feet and patients must have their feet assessed on diagnosis with T2DM and then annually thereafter. If deemed to be at risk of developing problems, they should be referred to the local foot protection service to be seen 2-8 weeks according to severity. Life-threatening foot problems, requiring immediate referral to the hospital, include ulcers with signs of sepsis or limb ischaemia, evidence of deep-seated soft tissue or bone infection, or gangrene.  

Problems that can arise include:

• Peripheral neuropathy – Crude touch, proprioception, fine touch and pain sensation should all be checked as well as motor function. Sensory deficit can lead to unknown injury and development of ulcers, Charcot arthropathy and skin infections. 
• Limb ischaemia – The lower limbs should be checked for vascular insufficiency including all pulses. Ankle-brachial pressure index (ABPI) can be used to assess evidence of arterial disease, but results must be viewed in the context of diabetes where calcification of vessels can elevate the measurement. Vascular insufficiency, either arterial or venous, leads to poorer wound healing and exacerbates problems such as ulceration and wound infections.
• Ulceration – A combination of neuropathy and vascular disease can lead to the formation of neuropathic, venous and arterial ulcers. A summary of the difference can be found in the table below.

Table 4: Types of diabetic Ulcers

Adapted from NICE CKS Diabetic foot problem – prevention and management: https://www.nice.org.uk/guidance/ng19/chapter/Recommendations#diabetic-foot-ulcer, and Dermnet.nz – Diabetic foot ulcers: https://dermnetnz.org/topics/diabetic-foot-ulcer

• Charcot Arthropathy – Loss of sensation allows recurrent small traumas to occur to the foot, which over time cause destruction of the joint. Charcot will present as a unilateral red, hot and swollen joint that can be mistaken for DVT or cellulitis. Imaging will show bony destruction and general inflammation, similar in appearance to osteomyelitis. Due to the loss of sensation, the foot will be much less painful than should be expected or may be completely painless. Management in the acute phase involves immobilising the foot and avoidance of weight-bearing. Surgery may also be considered, although there is no consensus as to whether this should take place in the acute phase or its resolution. The overall aim of treatment is to limit deformity and allow the patient to walk on the affected foot.  
• Gangrene – Both wet and dry gangrene may occur. These patients should be referred to vascular surgery for consideration of debridement and amputation whilst being treated with antibiotics. 

When a diabetic foot infection is suspected, a sample should be taken from as deep in the wound as possible, ideally a soft tissue or bone sample but failing this a deep swab. X-rays should be taken to assess the extent of the infection and MRI should be used if there is concern about osteomyelitis. Antibiotics should be given empirically until wound samples have been processed:

Table 5: Choosing the right antibiotic for diabetic foot disease

Adapted form NICE CKS Diabetic foot problem – prevention and management: https://www.nice.org.uk/guidance/ng19/chapter/Recommendations#diabetic-foot-ulcer

Macrovascular complications

As discussed previously, hyperglycaemia and insulin resistance lead to an increase in the production of reactive oxygen advanced glycation end products which cause oxidative stress and modulate intracellular signalling. The resulting increase in inflammatory compounds accelerates the formation of atherosclerosis and creates a prothrombin state. Other important risk factors for cardiovascular disease such as obesity and lipid dysregulation are commonly associated with T2DM. These elements lead to a significant increase in risk of:

• Coronary artery disease – including myocardial infarction and heart failure. 
• Cerebrovascular disease – including strokes and TIAs.
• Peripheral artery disease – including critical ischaemic limb, acute limb ischaemia and intermittent claudications.

The specific management of these conditions remains the same as for individuals without T2DM and details can be found in their corresponding chapters. From diagnosis, the risk of T2DM patients developing these conditions should be assessed and steps taken to modulate factors such as obesity, glycaemic control, hypertension, smoking and lipid dysregulation.