The diabetic foot is prone to complications, as clearly indicated by the high number of hospital admissions amongst individuals with diabetes due to foot problems. What may seem like a ‘simple’ foot ulcer can easily lead to an amputation. Sadly, a leg is amputated every 30 seconds, with up to 70% of all leg amputations happening to individuals with diabetes. Yet up to 85% of amputations can be avoided with preventative measures and adequate care.
Diabetic Foot Ulcers – Treat as an Aggressive Cancer!
Diabetic foot complications, including amputations, can be avoided by:
- applying a preventative approach through cost-effective strategies
- identifying high risk individuals and providing them with related health literacy eg. to check their feet daily, dry them thoroughly, and wear appropriate footwear
- knowing when a diabetic foot ulcer has become a complicated lesion: ischaemia and infection
- knowing which and when to apply a proper off-loading device
- providing continuity in treatment and management between hospital and the community, along with organisation and communication between both settings
However…
- 5% of individuals with new ulcers die within 12 months following their first physician visit regarding a foot ulcer
- 42.2% of individuals with foot ulcers die within 5 years
- 70% of diabetic foot ulcers recur over the following 3 years
“When people with diabetic foot ulcers heal, just like with cancer, they are not really healed. Our patients are in remission. We tend to think about wounds when they are open but why don’t we think about them when they are closed?
We should be aiming for having people at home in diabetic foot remission monitoring themselves”
Armstrong, Boulton and Bus, 2017.
Diabetic Foot Lesions Risk Factors
Routine Diabetic Foot Screening
1. COLLECT MEDICAL HISTORY
- ask regarding any previous foot ulcers or lower extremity amputations
- assess regarding poor access to healthcare and financial constraints
- ask if patient is experiencing foot issues eg. foot pain (walking or resting), numbness, claudication (pain whilst walking or using arms – may be a symptom of peripheral artery disease)
- ask if patient is experiencing dyspnoea
- ask if patient has end stage renal disease
2. INSPECT & ASSESS FOOT
- assess skin colour, temperature, and for callus or oedema presence
- assess for lesions such as pre-ulcerative signs, active ulcers, fissures, cracks and blisters
- check for bone and joint deformities eg. claw or hammer toes, abnormal large bony prominences, or limited joint mobility
- check if patient is using ill-fitting or inadequate footwear
- inspect patient feet for poor feet hygiene eg. improperly cut toenails, unwashed feet, superficial fungal infections, or unclean socks
- notice any patient physical limitations that may hinder proper foot care eg. obesity, visual impairment, etc.
- question patient on foot care health literacy – see what patient education is required for better self-care
3. ASCERTAIN PATIENT UNDERSTANDING & EDUCATION
- explain the screening process and the rationale behind it
- provide reassurance in case of anxiety
- provide patient education, counseling and support whilst screening the patient’s feet
- following screening, provide results to the patient, including any risks for foot problems, both in verbal and written form, along with contact details in case of any future questions
Peripheral Arterial Disease
Peripheral arterial disease is the main cause of delayed healing in the diabetic foot, associated with neuropathy in about 80% of all cases:
- macroangiopathy – similar to atherosclerosis, but is distributed in the distal segments of the lower extremities i.e. the calf and foot arteries
- arterial calcification – ‘hardening of the arteries’ – calcium forms hard crystals in the blood vessel walls
- microangiopathy – thickening of the capillary basement membrane which compromises gaseous exchange
Assessing Dorsalis Pedis & Posterior Tibial Pedal Pulses
- absence of both pedal pulses on one foot strongly suggests pedal vascular disease
- if no pulse can be located, refer patient to a vascular specialist or a relevant health professional for further assessment
NOTE: further examinations which need to be performed by a trained healthcare professional include the Ankle Brachial Pressure Index (ABPI), Systolic Toe Blood Pressure (STBP), and the Toe Brachial Pressure Index (TBPI)
Diabetic Neuropathy
Up to 70% of individuals with diabetes have mild to severe forms of nervous system damage. This includes:
- impaired sensation or pain in extremities
- slow food digestion in the stomach
- carpal tunnel syndrome
- other nerve issues
With diabetic peripheral neuropathy, one may not be able to feel:
- temperature changes
- pressure
- pain
- vibration
NOTE: individual with peripheral neuropathy may also experience painful sensory neuropathy which includes burning and tingling sensations a.k.a. paresthesia.
The Motor Neuropathic Diabetic Foot
Neuropathic foot features include:
- predominant neuropathy
- adequate circulation
- palpable pulses
- warm, dry, and often painless
Complications include:
- muscle weakness
- muscle twitching
- muscle paralysis
- neuropathic ulcer commonly found at the sole of the foot
- charcot foot
- neuropathic oedema
Neuropathic Ulcer
Charcot Foot
Charcot foot is a condition that causes bones in the foot to weaken, leading to fractures and shape changing. This typically occurs in individuals with neuropathy.
Neuropathic Oedema
The Neuro-Ischaemic Diabetic Foot
Neuro-Ischaemic foot features include:
- neuropathy
- absent foot pulses
- feels cool to touch
- thin, shiny, hairless skin
- subcutaneous tissue atrophy
- increased pain at rest (may be absent due to neuropathy)
The Ischaemic Diabetic Foot
Ischaemic foot features include:
- peripheral vascular disease
- absent signs of peripheral neuropathy
- cold, shiny, hairless skin
- rare in diabetic patients
Diabetic Foot Assessment
To perform a diabetic foot assessment, shoes, socks, and any would dressings from both feet should be removed. This should be followed by a thorough examination for evidence of the following risk factors:
- ulcers
- callus
- gangrene
- deformity
- infection
- inflammation
- charcot foot
- limb ischaemia
- neuropathy
Wound Assessment and Description
Assessing Sensation with a tuning fork
Assessing for Neuropathy using 10g Monofilament
Assessing for Vascular Problems
- Is lower limb blood supply adequate for normal function and tissue viability?
- Can you identify any arterial or venous vascular problems which may compromise the current state of the tissues?
- Are there any vascular abnormalities that may affect the patient’s healing or treatment options?
- What can you do to avoid possible complications?
- Does the patient have a vascular condition that requires further investigations by a specialist?
Calculating Ankle-brachial index
Osteomyelitis
Foot Ulcer Treatment – Key Elements
- providing local wound care
- providing pressure relief for ulcer protection
- providing infection treatment
- restoring skin perfusion
- preventing recurrence
- treating or controlling other comorbidities eg. diabetes
- providing related health literacy to patients and their relatives
Provide the patient with oral and written information in detail, including information about diabetes control, foot emergencies, and contact person details.
Offloading
Offloading promotes reduction, redistribution, or removal of detrimental forces applied to the foot. Offloading alleviates pressure at areas of high vertical and shear stress.
Foot plantar pressure is the pressure field which acts between the foot and the support surface during everyday activities. The main aim of offloading devices is to redistribute plantar pressures evenly, which helps avoid areas of high pressure that prevent or delay healing.
Retrieved from https://www.researchgate.net/publication/269766812_The_Management_of_Diabetic_Foot_Ulcers_Through_Optimal_Off-Loading_Building_Consensus_Guidelines_and_Practical_Recommendations_to_Improve_Outcomes/figures?lo=1 on 3rd July 2022
References
Armstrong, D., Boulton, A., & Bus, S. (2017). Diabetic Foot Ulcers and Their Recurrence. The New England Journal of Medicine, 376(24), 2367-2375. Retrieved from http://81.143.226.227/Medicine/Papers/2017_06_15%20NEJM%20Diabetic%20Foot%20Ulcers%20and%20Their%20Recurrence.pdf on 2nd July 2022.
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