Diabetic foot ulcer

Rapid treatment of all foot problems

By: Mölnlycke Health Care, December 16 2011Posted in: Diabetic foot ulcer

Rapid management by a team of healthcare professionals skilled in the various facets of diabetic foot ulcer management has been shown to be necessary to achieve optimal outcomes as early as 1986 (Edmonds et al 1986) and has been reiterated in many guidelines (IDF 2005, NICE 2004).

The core elements of management can be split into six components: debridement or wound bed preparation, infection control, metabolic control, vascular control, pressure relief and wound management.

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Moisture balance

A moist wound environment is known to encourage healing by promoting granulation and encouraging debridement by autolysis9. However, moisture balance must be maintained to prevent the wound bed becoming too dry or too moist, both of which could contribute to a delay in wound healing.

Dressing selection should ensure moisture balance and create an optimum environment for healing. In a chronic wound such as a DFU, the wound exudates contain enzymes which damage the healing process.  To maintain an optimal moist wound environment whilst protecting the surrounding skin from maceration, key characteristics are required.

They must absorb and retain exudate, keep harmful chronic wound exudate away from the surrounding skin, perform efficiently when used in weight bearing areas on the plantar surface of the foot, be easy to remove and be demonstrated as cost-effective.

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Debridement

Debridement is the “removal of devitalised or contaminated tissue from within or adjacent to a wound until surrounding healthy tissue is exposed”.

Rational for wound debridement

  • Allows true dimensions of a wound to be perceived
  • Removes pressure (callus) from the edge of the wound
  • The presence of slough/necrosis delays or prevents wound healing
  • Allows drainage of exudate
  • Enables deep swab to be taken
  • Restores a chronic wound to an acute wound
  • Devitalised tissue provides an ideal medium for bacteria to grow
  • Once devitalised tissue has been removed wounds have the opportunity
    to progress to healing
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Wound care

Attention to the wound characteristics are vital to create the right environment for the wound to heal. Attention to debridement and systemic infection are described above but the role of bio-burden, exudates management  and healing need to be considered.

Increase in bioburden

Terms used to describe the ’bacterial bio burden’, or different levels of bacteria on the surface of an ulcer, include ’contaminated’, ’colonised’ or ’infected’, and obtaining a degree of bacterial balance have been cited as a key objective in successful wound care10. It is established that increase in bacterial load may delay healing, cause failure of healing, and even cause wound deterioration11.

Increase in bio burden can be managed locally with debridement and antimicrobial dressings. The major benefits of antimicrobial dressings are that they can reduce bioburden, decrease the risk of infection, and create an environment that readily supports the normal sequence of wound healing12. The main rationale for using antimicrobials on DFUs is the prevention and treatment of bio-burden and a subsequent increased rate of the healing process.

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Pressure relief

Relieving pressure from the ulcer is a key component of care. In fact, without some attempt to address this issue wound care will at best be compromised and at worst ineffective. Providing equipment, such as crutches or a wheelchair, will encourage the most effective approach which is non-weight-bearing. In most cases this is difficult to achieve and at best patients will reduce their activities, especially when faced with living with a potentially chronic wound. Listening to the patient and negotiating a workable approach to this issue is of course the best approach. Complete pressure relief (i.e. no pressure taken on the area) is difficult to achieve with the majority of devices used, particularly when addressing weight-bearing areas of the foot hence, pressure reduction is the ‘realistic’ aim of intervention.

Unfortunately there is not a wealth of research literature available that compares approaches commonly used to address this issue. However, the International Working Group on the Diabetic Foot6,7 recommends consideration of the use of a total contact casting (TCC) in treatment of neuropathic, non-infected, non-ischaemic plantar diabetic foot ulcers and this is often regarded as the gold standard based on the available evidence. Further advice given by this group suggests cast shoes and cast boots as alternative modalities.

If neuroischaemic ulceration is also considered, the Scotchcast boot is an option13. More recently, synthetic semi rigid casting techniques, involving the use of slipper casts and below knee casts, have been trialled as an alternative with both neuropathic and neuroischaemic foot ulcers4. Adhesive felt aperture padding, directly adhered to the skin, is not currently recommended for use in the management of foot ulceration due to infection control issues.

Removable walkers are an alternative to casting techniques. However, the removable nature of these devices reduces their effectiveness and it is recommended by the IWGDF that they are made ‘irremovable’ to increase healing percentages to a level comparable with the TCC.

During active ulceration, therapeutic footwear (i.e. stock or bespoke ‘orthopaedic’ footwear) is not recommended but may be the only approach for some very complex cases. An alternative to this is a bespoke removable walker in cases of significant deformity and severely altered foot and leg biomechanics.

The final choice of pressure relief or reduction modality will depend on the available evidence and a variety of factors, including ease of use, safety and appropriateness for all activities (e.g. bed, sitting and transferring). Ultimately the approach must work in conjunction with dressing choice; dressings contribute to protecting the foot but do not provide pressure relief.

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Vascular control

It is essential to determine the vascular status of the foot; findings will largely influence ulcer management, determine the likelihood of wound healing and identify the need for revascularisation3,6,7 recommend: Palpation of foot pulses – Palpation of dorsalis pedis and posterior tibial pulses should be undertaken. If pulses are not palpable or arterial disease is suspected, other tests such as Doppler examination and ankle: brachial pressure index (ABPI) should be undertaken.

Determining whether the patient is experiencing vascular symptoms, for example, intermittent claudication (i.e. pain in the calves on walking) or rest pain( constant pain in the feet and legs aggravated by lying flat or the warmth of bed clothes. If there is concern of significant peripheral arterial disease, expert advice from the vascular team should be sought. Efforts should be made to manage arterial risk factors in those who have suspected poor blood flow. Certain factors are known to increase the risk of arterial disease, for example, high blood pressure and high cholesterol.

These factors should be identified and management strategies that aim to minimize arterial risk factors introduced. The IDF6,7 recommend attention to blood pressure, dyslipidaemia (abnormal lipid levels in the blood) smoking cessation and the use of anti-platelet agents such as aspirin.

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Metabolic control

High blood glucose levels can increase the risk of complications arising. It is well-established that high glucose levels increase the risk of vascular disease but they can also give rise to neuropathy and increase infection risk14. Failure to improve the person’s blood sugars can impact on their healing rate and reduce their ability to fight infection.

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Infection control

Optimal management of diabetes related foot infection can potentially reduce the incidence of infection related morbidities, the need for and duration of hospitalisation and the incidence of major limb amputation15,16. Infection in the diabetic foot has been classified into mild, moderate and severe (see table 1) to help guide treatment regimes. In all these cases appropriate antibiotic therapy is the treatment of choice. An empirical antibiotic regimen should be based on the severity of infection and the likely aetiological agents17. There is limited evidence with which to make informed choices among the various antibiotic agents.

Foot ulcer severity

Mild

Presence of 2 or more signs of inflammation (pus, erythema, pain, warmth, tenderness, induration). Cellulitis if present < 2cm from the ulcer in the absence of clinical signs of systemic toxicity and infection involving the superficial tissues.

Moderate

As in ‘mild’ above, with cellulitis > 2cm from the wound but <5cm; no signs of systemic toxicity; infection is spreading to deeper tissue and bone.

Severe

Extensive cellulitis, deep abscess with or without signs of systemic toxicity (fever, vomiting, hypotension, confusion, acidosis, renal failure, severe hyperglycaemia, leukocytosis).

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