Everyone with diabetes should have an annual foot assessment by a healthcare professional (GP, practice nurse or hospital-based diabetes team), to assess the feet for problems related to circulation and sensation. The healthcare professional should advise the patient about the risk of developing foot problems and also give instructions on the day-to-day care of feet.¹

General diabetes management also affects the diabetic foot, so it’s important for people living with diabetes to keep up with a healthy diet, the correct amount of exercise, taking medications as prescribed and regular diabetes assessments.

The recommended target HbA1c in diabetes patients currently lies at less than 53mmol/mol and patient blood glucose levels should be in the range of 5-8mmol/l.

Prolonged above-target blood glucose levels can cause damage to the nerves and the blood vessels that supply the feet. Damage to the nerves (neuropathy) can cause symptoms such as tingling and numbness, not being able to feel pain or temperature as normal, or burning and shooting pains. Narrowing of the blood vessels in the legs is called peripheral vascular disease (PVD) which can also be caused by prolonged high blood glucose levels.¹

Diabetic ulceration

Diabetic ulceration is characterised by:

• Wounds that take longer to heal

• Wounds that will not heal without help

• Wounds are usually unable to heal quickly or at all due to reduced vascular function

• Poor healing rates: weeks, months or even years.

Due to the prolonged time to heal, diabetic ulceration can affect mobility and exercise, and therefore can have a knock-on effect on glycaemic control which increases the likelihood of complications, including altered mood which may lead to depression.

Diabetic neuropathy

Diabetic neuropathy, another term for nerve damage or nerve destruction, is caused by poorly controlled and/or fluctuating blood glucose levels. Neuropathic pain affects one-quarter of people with diabetes.

Destruction of neuro/vascular function happens naturally with age, and as diabetes is a progressive disorder, neuro/vascular reduction will happen, especially after some years.

Many may have diabetes for as long as six months to seven years before diagnosis, and neuropathic changes may have commenced during this time.

Peripheral vascular disease

Peripheral vascular disease (PVD) is a slow and progressive circulation disorder caused by narrowing, blockage or spasms in a blood vessel.

PVD may involve disease in any of the blood vessels outside of the heart, including the arteries, veins or lymphatic vessels.

Organs supplied by these vessels, such as the brain, and legs, may not get enough blood flow for proper function.

Legs and feet are most commonly affected, thus the name peripheral vascular disease. The terms ‘peripheral vascular disease’ and ‘peripheral arterial disease’ are often used interchangeably.

PVD is often characterised by a narrowing of the vessels that carry blood to the leg and arm muscles. The most common cause is atherosclerosis, the build-up of plaque inside the artery wall. Plaque reduces the amount of blood flow to the limbs and decreases the oxygen and nutrients available to the tissue.  Clots may form on the artery walls, further decreasing the inner size of the vessel and potentially blocking off major arteries.²

Model of care for the diabetic foot

The HSE launched a model of care for the diabetic foot in 2011,³ which is available on the HSE website, www.hse.ie

The model of care provides clear guidance on diabetes footcare and is stratified according to the risk attributed following a foot assessment. An overview of the risk categories can be seen in Table 1. 

During the annual foot assessment, the healthcare professional should test neurological and vascular function.

Neurological testing

• Hot and cold: Does the patient know the difference between the two, with eyes closed?

• 10g monofilament: Can the patient feel it in different areas of each foot, with eyes closed?

• Vibration: Does the patient know the difference between vibrating and non-vibrating 128Hz tuning fork?

• Neurotip, blunt and sharp: Does the patient feel the difference between the two, with eyes closed?

• Proprioception: Holding on to Hallux (the big toe) on each foot in turn, with eyes closed, can the patient tell you if the toe is up, middle or down?

• Plantar reflex: Does the patient react by curling toes or not?

Vascular testing

• Check colour of both feet: Pink (good circulation); red/shiny, purple, blue, white (poor circulation); in comparison to natural skin colour. Bright red (infection), dull red (healing)

• Palpate dorsalis pedis and posterior tibia: If palpable, it indicates fair to good circulation

• Doppler if needed: tri-phasic, bi-phasic, mono-phasic (good, moderate, poor circulation); regular/irregular; slow, medium or fast beat

• Capillary refill: 2-5 seconds good, either side of this indicates poor circulation.

The diabetic foot

Studies have shown that people with diabetes are over 20 times more likely to undergo a lower-extremity amputation (non-traumatic) than people without diabetes.^4,5 A study by Khanolkar et al⁶ has also shown that up to 80% of people with diabetes who have undergone an amputation die within five years.

According to the International Diabetes Federation,⁷ up to 80% of amputations are actually preventable, but daily footcare is vital. With one-in-seven people with diabetes developing foot ulcers within their lifespan, it is clear that basic good footcare needs to be established early on in diabetes management. 

Daily footcare to prevent problems

To prevent foot problems, daily footcare should include:

• Examining the feet daily including in between the toes looking for any discolouration, bleeding, weeping or discharging, broken or hard skin, or problem toenails 

• Washing the feet in lukewarm water and drying thoroughly, especially between toes. Moisturise the feet, but do not moisturise between toes

• Wearing clean cotton socks daily, ensuring they are not too tight

• Walking barefoot should be avoided

• Examining footwear before putting them on to ensure that nothing will cause injury

• Footwear should provide support and be soft, cushioned and seamless with laces or a soft strap to fasten. Slip-on shoes should be avoided

• Hot water bottles should be avoided, as should sitting too close to a fire or radiator in case of burns

• Corn plasters are not advisable for people with diabetes as they may burn the skin

• If due to a visual impairment or a physical disability the patient is unable to manage their own footcare, a family member should be asked to help or the patient should be advised to have regular podiatry treatments

• The patient should be advised to contact their doctor or podiatrist without delay if any foot problems are detected

• If minor cuts, cracks or blisters are found, these should be cleaned with a salt water bath, either:
– washing-up bowl with two inches of boiling water (allow to cool until warm) with two to three handfuls of salt for a two- to three-minute soak
– coffee/tea mug with half boiling water half salt (allow to cool until warm) using gauze or cotton wool balls, dabbing two to three times

• Dry well and cover with dry dressing

• If wounds are red, inflamed, hot or painful, seek help via GP, nurse, podiatrist or emergency department to get antibiotics.¹

It is also important to stress smoking cessation in people with diabetes, as smoking dramatically increases circulation damage. Any wounds or ulcerations need to be treated and dressed by professionals only.

Patient information leaflets on footcare are available on the HSE website www.hse.ie, search for ‘footcare information leaflets’. Three leaflets are available on low risk, medium risk and high risk feet respectively.

References

1. Williams G, Pickup JC. Handbook of diabetes. 3rd edition. Wiley 2004
2. Peripheral vascular disease, John Hopkins Medicine Health Library as accessed on http://www.hopkinsmedicine.org/healthlibrary/conditions/cardiovascular_diseases/peripheral_vascular_disease_85,P00236/
3. Model of care for the diabetic foot. HSE 2011, as accessed on https://www.hse.ie/eng/about/Who/clinical/natclinprog/diabetesprogramme/modelofcarediabetes.pdf
4. Buckley CM, O’Farrell A, Canavan RJ, et al. Trends in the Incidence of Lower Extremity Amputations in People with and without Diabetes over a Five-Year Period in the Republic of Ireland. 2012, http://dx.doi.org/10.1371/journal.pone.0041492
5. Holman N, Young RJ, Jeffcoate WJ. Variation in the recorded incidence of amputation of the lower limb in England. Diabetologia 2012; 55: 1919-1925
6. Khanolkar MP, Bain SC, Stephens JW. The diabetic foot. QJM 2008; 101: 685-95
7. IDF Clinical Guidelines Task Force (2005) Global Guidance for Type 2 diabetes. Brussels: International Diabetes Federation as accessed on http://www.idf.org/sites/default/files/IDF-Guideline-for-Type-2-Diabetes.pdf