1. Diabetic neuropathy Wound healing
Section 5 | Part 4-II of 4
Curriculum Module III–7c | Diabetic neuropathy
Slides current until 2008

2. Neuropathy – principal problem Vascular disease – secondary
The diabetic foot
Neuropathy – principal problem
Vascular disease – secondary
Peripheral neuropathy is the most common cause of diabetic foot ulcers.
Peripheral vascular disease is the most important factor in the outcome of diabetic foot ulcers.
Slides current until 2008

3. Neuroischaemic ulcers
Four types of ulcers
Neuropathic ulcers
Ischaemic ulcers
Neuroischaemic ulcers
Venous ulcers
Lower-limb ulcers in people with diabetes can be classified as either neuropathic, ischaemic or neuroischaemic.
For the purposes of this presentation, venous ulcers will not be discussed.
Neuropathic ulcers are the most common of all diabetic foot ulcers, accounting for approximately 45% to 60%.
Ischaemic ulcers that occur in the poorly perfused diabetic foot are rarely caused by the vascular disease itself; there is usually some precipitating trauma, such as knocking the foot.
In addition to the purely neuropathic and ischaemic ulcers, there is a mixed group of neuroischaemic ulcers.
Slides current until 2008

4. Mixed? predominant pathology? Determine wound management Act quickly
Determine aetiology
Neuropathic?
Vascular?
Mixed? predominant pathology?
Determine wound management
Act quickly
It is important to determine the type of wound you are dealing with as this will help you plan your management and to act as quickly as possible.
Slides current until 2008

5. Low-to-moderately exudative
Neuropathic ulcers
Area of pressure
Callus
Red granulating base
Low-to-moderately exudative
Bounding pulses
Painless
How can you differentiate between neuropathic, ischaemic or neuroischaemic foot ulcers?
In most cases, the type of ulcer can be identified quickly by assessing the location, characteristics and clinical signs.
Neuropathic ulcers are located in areas of pressure, such as tips of toes and bony metatarsal heads.
As in the photograph, these areas are usually surrounded by callus – the body’s direct response to pressure. The ulcer’s base usually has granulating tissue. The level of exudate (pus) is low to moderate. These feet are well perfused, with bounding foot pulses, which indicate an ability to heal once pressure is reduced.
Due to nerve damage resulting in loss of sensation, people with a neuropathic foot ulcer will not experience pain.
Slides current until 2008

6. Intrinsic – biomechanical
How do neuropathic ulcers develop?
Neuropathic ulceration can occur due to intrinsic and extrinsic causes.
An intrinsic cause is the change in foot mechanics that occurs due to peripheral and autonomic neuropathy, together with high foot pressures.
Common foot deformities result, such as clawed toes and prominent metatarsal heads. These deformities lead to increases in pressure, resulting in callus formation and potential ulceration.
Callus formation is dangerous on the insensate foot, is not protective, and should be debrided promptly and regularly – at least fortnightly.
Slides current until 2008

7. Extrinsic – thermal
People with severe neuropathy are susceptible to external injury.
Heat-related injuries are common, especially in winter. People burn themselves by sitting too close to heaters (they should sit at least 3 m away), using a hot water bottle or immersing feet in hot water (see slide).
Summer is also a time when burns occur; people walk barefoot on hot sand at the beach or on hot footpaths or roads.
Slides current until 2008

8. Extrinsic – footwear
The majority of external foot trauma is due to ill-fitting footwear.
This man tied his shoelace so tight that the top of his shoe rubbed the skin, creating blisters and ulcerations.
Foreign objects in people’s footwear, such as nails, screws and glass, also cause trauma and ulceration.
People cannot feel these objects inside their shoe and continue walking, injuring their feet.
Slides current until 2008

9. Extrinsic – chemical
Additionally injury can result from chemical cures for corns, which can burn the skin of the insensate foot, creating an ulcer.
Slides current until 2008

10. Management of neuropathic ulcers
Treat infection
Debridement of callus
Reduce pressure
Restrict walking
Dressings
Before treatment of any foot ulcer, people must receive an explanation of their foot condition, its treatment and the rationale behind this. The treatment of infection is the first priority.
Diabetic foot infection is generally under-diagnosed and under-treated. Treatment with antibiotics should be started empirically; infection can greatly increase the likelihood of amputation. The patient should continue on antibiotic therapy until the ulcer is close to healing. It is recommended not to wait for the results of a wound swab before starting antibiotic therapy.
The reduction of pressure at the ulcer site is an essential component in healing foot ulceration. Evidence has shown that callus removal reduces pressure at the ulcer site by 26%.
Reductions in pressure can also be achieved using an offloading device such as an airflow mattress, a bed cradle, a pillow, or special footwear, which we will look at shortly.
It is important to evaluate footwear, which frequently is not conducive to wound healing – too small or narrow. People must be taken out of footwear that causes problems and placed in appropriate footwear, such as all-purpose boots.
People with a foot ulcer must be advised to reduce their walking, weight bearing or sitting in one position for prolonged periods, which is enough to traumatize the ulcer and prevent healing. People should only do what is required to fulfill the basic activities of daily living. Peole with ulceration or a previous history of ulceration and/or amputation should not do any weight bearing exercise.
Dressings are an adjunct to treatment and facilitate wound healing.
It is best to become familiar with a small group of dressings for ulcers.
Slides current until 2008

11. Pre- and post-debridement
The removal of all visible callus and non-viable tissue at weekly intervals is crucial to breaking the vicious cycle of pressure generation.
Also, debridement promotes healing by stimulating the chronic wound into an acute wound.
Slides current until 2008

12. Impractical for exudating ulcers
Felt deflection
Reduces pressure by 61%
Simple and cheap
Replace weekly
Impractical for exudating ulcers
Risk of tinea/skin tears
Felt with an adhesive backing is commonly used by podiatrists to reduce and deflect pressure from ulceration and bony prominences.
Studies have shown that pressure can be reduced by 61%.
The approach is simple to use and cheap. However, it needs to be replaced after one week.
The felt can be placed on the skin or inside an all purpose shoe or a shoe with adequate depth.
Felt is not to be used if the ulcer is highly exudative or the skin too fragile.
Slides current until 2008

13. Ulcer healing with felt deflective padding
Week 1: pre-debridement Week 1: post-debridement
Week Week 6: healed
Slides current until 2008

14. Less effective in maintaining foot shape
Pre-fabricated casts
Simple to use
Will not fit all feet
Removable
Less effective in maintaining foot shape
Pre-fabricated casts are an effective alternative to the total contact cast.
Their rocker sole provides effective offloading for plantar ulcers.
They are simple to apply and can be easily removed by the healthcare provider for monitoring and by the patient for foot inspection.
However, pre-fabricated casts may hinder adherence, especially in those who choose to remove it.
Because they are an ‘off-the-shelf device, they will not fit all feet and are less effective in maintaining foot shape.
The Aircast Diabetic System with an inflatable bladder is the most effective as it has the ability to be customized with use of the air-bladder.
An advantage of a prefabricated cast is that it can be padded with custom-moulded insoles.
Slides current until 2008

15. On toes and foot margins Pale granulation, sloughy tissue or eschar
Ischaemic ulcer
On toes and foot margins
Pale granulation, sloughy tissue or eschar
Dry with irregular borders
Painful
Pulses weak or impalpable
Ischaemic ulcers are relatively rare compared with neuropathic ulcers but it is most important that we able to identify them as their treatment is different.
These ulcers present on feet with impalpable or weak pulses.
They are found on the borders of feet or the tips of toes, or in between the toes.
Ischaemic ulcers may present with dry eschar (dead tissue) or have a sloughy ulcer base, and are usually irregular and non-exudative. These ulcers are usually painful.
Slides current until 2008

16. Management of ischaemic ulcers
Vascular assessment and treatment
Treat infection
Pain management
Dressings
Avoid compression/bandaging
Again, it is important to explain the nature of the problem, the treatment required and, in this case, the prognosis. These ulcers usually take a long time to heal; vascular intervention is often required.
A more cautious approach to managing ischaemic ulcers is essential as their ability to heal is impaired. Check the ulcerated foot for signs of infection. Remember that inflammatory signs (redness and heat) may be absent due to the lack of blood supply.
Reviewing infection status regularly is essential. Pain management should be considered in people with ischaemic ulcers.
Do not use sharp debridement or dressings that debride the wound until you have information regarding blood supply or have permission from the patient’s vascular specialist.
Protect the area with black eschar with a non-stick dressing.
If the ulcer base is sloughy and exudative, a dressing is required to absorb the pus.
Do not use compression stockings or bandages unless advised by a vascular specialist as they may further reduce blood flow.
Slides current until 2008

17. Optimize wound healing environment
Treatment goals
Control infection
Improve blood supply
Optimize wound healing environment
Protect wound from trauma
Controlling infection, improving blood supply and optimizing the wound healing environment are essential in achieving effective wound healing.
However, it is extremely important to protect the foot/ischaemic ulcer to reduce the risk of trauma-related injuries.
Assess footwear for suitability.
Post-operative shoes or sheepskin boots are good alternatives.
Protecting heels in bed also needs consideration.
Slides current until 2008

18. Neuro-ischaemic ulcer
Mixed neuropathic and vascular processes
One process more dominant
Need to assess
The neuro-ischaemic ulcer has a combination of neuropathic and ischaemic characteristics.
In order to determine the more dominant process, a thorough neurological and vascular assessment is essential.
Treatment will depend on these results.
Slides current until 2008

19. Practice tips: neuropathic ulcers
Foams 2 cm larger than the wound
Use gels sparingly
Keep foot dry – wash separately
Do not use occlusive dressings
Extra pads increase pressure and occlude the wound
Alginate and hydro-fibres should be cut to wound size.
Gel applied to weight-bearing ulcers must be used sparingly to avoid maceration of the area surrounding the wound. Hydrogel-impregnated products, which assist in keeping gel within the wound, are ideal.
Occlusive dressings may mask infection, retain wound exudate, macerate and retard healing, and precipitate the breakdown of the surrounding skin. These are contraindicated in the presence of exposed bone/tendon.
Peri-pads and crepe bandages increase pressure and overheat the ulcer; avoid over-wrapping the wound.
Slides current until 2008

20. Practice tips: ischaemic ulcers
Gels contraindicated in the presence of ischaemia
Do not debride
Do not use compression
Keep foot dry in shower and wash separately
Be very careful with tapes to prevent skin tears
Debridement and use of gel is contraindicated when pulses are not palpable, the ABI is not known or below 0.5.
These may enlarge the wound and macerate the surrounding ulcer area when there is inadequate blood supply to support healing.
The skin of ischaemic feet tends to be dry and fragile. Tapes may therefore cause tearing.
Slides current until 2008

21. Elevated blood glucose levels
Foot infection
Swelling, redness, heat
Odour from ulcer
Increase in exudate
Failure to heal
Elevated blood glucose levels
Pain may not be present if the person has loss of sensation. Signs of inflammation may be absent in people with severe ischaemia.
As stated previously foot infection is under-recognized and under-treated. When assessing infection it is important to compare both feet and lower limbs for differences (noting swelling, redness and heat).
When the wound is dirty or smelly, suspect the presence of anaerobic infection. This can be treated with appropriate antibiotics.
When an ulcer is highly exudative it may indicate the presence of a sinus (deep tract). Sinus need probing to determine their depth.
People most susceptible to infection are those who have poorly controlled diabetes (HbA1c >10%) and those who live in hot, humid climates.
Remember the person may not feel pain due to the neuropathy and therefore may not complain of any discomfort.
Slides current until 2008

22. In diabetes, clinical signs may be masked leading to delayed diagnosis of infection.
Slides current until 2008

23. Do not withhold antibiotics until results of culture available
Rely on clinical judgement
Slides current until 2008

24. Antibiotic treatment is an essential aspect of treating diabetic foot ulcers – maintain until ulcer has healed. Depending on clinical response, frequent changes and long-term antibiotics may be required.
Slides current until 2008

25. Ulcer = risk of infection Osteomyelitis (sausage toe) Amputation
Foot infection
Ulcer = risk of infection
Osteomyelitis (sausage toe)
Amputation
Infection alone in the diabetic foot increases the risk of amputation.
However, in the presence of an ulcer there is always the risk of infection spreading to deeper tissues and into bone with rapidity – causing osteomyelitis.
Infection in the bone has been shown to be present in more than 60% of infected diabetic foot ulcers and is associated with significant morbidity and amputation.
Slides current until 2008

26. Treatment of osteomyelitis
Antibiotics
minimum of 3 months until there is evidence of healing on x-ray or scan
Infected bones may need to be removed surgically
While you may not be the person prescribing the antibiotics it is essential you know what the person needs and help ensure they remain on antibiotic therapy until the infection has healed.
A repeat x-ray or scan should be performed to check for resolution of the osteomyelitis.
If surgical removal of bone is necessary the person should remain on antibiotics until after the surgery.
Slides current until 2008

27. Prevention of the diabetic foot disease
Primary prevention
No successful clinical trials
Metabolic control
Smoking cessation
Secondary prevention
Identify high risk feet
Foot education
Foot care
Management of active foot problems (ulceration)
Preventing diabetic foot disease requires a multidisciplinary approach.
Although there are no clinical trials indicating specific methods to prevent foot complications, we know that achieving good glycaemic control can maintain nerve function; smoking cessation can reduce the risk of peripheral vascular disease.
Prevention also requires the identification of high-risk feet and the delivery of foot education and podiatry for these people. It is important for people to know when and where to refer if ulceration/infection occurs.
Slides current until 2008

28. Arrange appropriate wound management
Key points
Assess
Determine aetiology
Arrange appropriate wound management
In summary, key footcare messages are:
Assessment is essential
Once done, it will help in determining the aetiology of the condition
Knowing the aetiology will guide arrangements for appropriate wound management, if possible, by a skilled multidisciplinary team.
Slides current until 2008

29. Case study 70-year old man Type 2 diabetes Diabetes for 35 years
Smoker for 35 years
Ask participants to work in pairs to evaluate the case history illustrated in the following slides. Feedback to the whole group.
Slides current until 2008

30. Right hallux (great toe) ulcer – had bypass now ABI improved to 1.00
Case study
Pulses absent
ABI’s
Left
Right
Left 1st MPJ ulcer
Right hallux (great toe) ulcer – had bypass now ABI improved to 1.00
His ankle brachial index on the left was 0.69 and on the right was 0.71 indicating severe arterial disease.
There was an ulcer on the first metaphalangeal joint or in other words under the ball of the foot.
There was also an ulcer on the great right toe but following bypass surgery blood flow improved as indicated by the normal Ankle Brachial Index of 1.
Slides current until 2008

31. Case study Biothesiometer >50 volts Monofilament cannot feel
Reflexes
absent
Slides current until 2008