Diabetes & Foot Ulceration
What is diabetes foot ulceration?
Foot ulceration is a common complication of diabetes and refers to a patch of broken down skin exposing the layers below. They are most common under the big toe, outer aspect of the little toe, heel and tips of the toes.
Is diabetes foot ulceration common?
Yes. The incidence of diabetes foot ulceration in the USA and Western Europe is 2-6%, with a lifetime risk and recurrence rate of 10-25% and 25%, respectively.
Why is diabetes foot ulceration important?
Ignored or inadequately treated, these ulcers are usually the first step to lower limb amputation, with 5% of patients undergoing an amputation within one year of ulcer onset and 80% of all amputations in patients with diabetes being preceded by foot ulceration.
What causes diabetes foot ulceration?
Diabetes foot ulceration is caused by abnormal weight loading through the foot and impaired tissue blood perfusion secondary to the combined effects of ischaemia (lack of blood supply), peripheral neuropathy (nerve damage) and infection (see fig. 1).
Why do patients with diabetes develop leg/foot ischaemia?
Peripheral arterial disease is common in patients with diabetes, classically causing narrowing or blockages in the arteries of the calf, thereby reducing the blood flow into the foot. This is further impaired by the simultaneously deleteriously effects diabetes has on the microscopic blood vessels (microvascular system) in the foot. Thus, diabetes affects both large arteries (macrovascular) and very small arteries (microvascular) making the circulatory requirements for healing tenuous. This alone has considerable implications on treatment strategies, and early recognition of arterial disease is vitally important to prevent subsequent amputations.
What is peripheral neuropathy and why does it cause foot ulceration?
Peripheral neuropathy is malfunctioning of the nerves that control touch, movement, and automated functions, such as sweating. Individuals with diabetes typically suffer a gradual onset that affects their feet and progresses up the leg in a symmetrical fashion. Typically, individuals notice numbness and pins and needles affecting the feet, that may progress to a burning type pain. The numbness renders these individuals at high risk of injury often from relatively innocuous causes, e.g. a stone in their shoe, as they are devoid of the protective pain reflexes (see fig. 2a). As the neuropathy progresses it may affect the bones and joints leading to repetitive joint injury and even bony fractures in the foot (see fig. 2b). Nerve supply to the muscles of the foot may also be impaired causing an imbalance between muscle groups leading to a change in the shape of the foot making it more susceptible to injury. Neuropathy and ischaemia often occur together (neuroischaemia) to initiate the development of a foot ulcer.
What role does infection play in diabetes foot ulceration?
More than half of all foot ulcers will become infected and often require hospitalization. Infection may initially be limited to the ulcer and surrounding skin. However, it is the ability of bacteria to spread quickly into deeper tissue planes, including tendons and muscles, that leads to 20% of all individuals with diabetes and an infected foot ulcer ultimately undergoing amputation. Thus, the prompt recognition and treatment of diabetes foot infection is vital to prevent subsequent amputation.
What investigations should be performed for diabetes foot ulceration?
During your review, your surgeon will aim to assess for the presence of ischaemia, neuropathy and infection utilising a combination of clinical assessment (symptoms review and examination) and specialized investigations. A combination of the followings tests may be recommended depending on your clinical presentation: Blood analysis to check for anaemia, kidney function, cholesterol levels Diabetes control assessment e.g. Hb1Ac Microbiological swab of ulcer Ankle brachial pressure index (ABPI) assessment Toe pressure assessment Electrocardiogram (ECG) Duplex Doppler ultrasound scan Foot x-ray CT angiogram MRI of the foot MR angiogram Diabetes represents a multi-morbidity chronic condition with patients with diabetes aged over 65 years being affected by an average of six other conditions including coronary artery disease, stroke and hypertension. For these patients, we may also recommend seeking a second opinion from another medical specialty to ensure we are addressing and optimising all your medical issues.
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Fig. 1: Synergistic relationship of ischaemia, neuropathy and infection in Diabetic Foot Ulceration causation (click to enlarge)
Fig 2: a) Early neuroischaemic foot ulcer, b) Gross disruption of foot joints due to neuropathy -Charcot's arthropathy
Fig. 3 Before and after angioplasty treatment of calf vessel (crural arteries) for Diabetic Foot Ulceration
What are the treatments for diabetes foot ulceration?
The treatments for diabetes foot ulceration are aimed at: a) Improving blood flow to the ulcer e.g. angioplasty (see fig. 3) or bypass, b) Preventing further trauma to the ulcer area e.g. pressure offloading footwear, c) Aggressively treating infection e.g. antibiotics or wound debridement. Occasionally diabetes foot ulceration leads to amputation despite our best efforts. At Circulation Clinic, we aim to minimize your risk of amputation through a timely and multidisciplinary approach to diabetes foot ulcer care. We work closely with orthopaedic surgeons, diabetologists and interventional radiologists to ensure you receive the best and most appropriate care available.