Case Study 2:
Challenges of assessment and management of pain
in an individual with a diabetic foot ulcer
Patient: Mr. Good, a 61-year-old male with a history of type 2 diabetes, active smoker (20 -30 per day).
Diagnosis: Diabetic foot disease (presence of peripheral diabetic neuropathy and mild peripheral arterial disease) with a painful left heel ulcer.
Presentation: The patient was referred to the Community Nurse with an ulcer on their left heel. The patient reported increasing pain over the past week particularly when walking. He also reported numbness and paraesthesia in the left foot and pain at rest. The patient reported some numbness and paraesthesia in both feet all the time. Pain was assessed using the numerical rating scale (NRS 0-10 point) with a pain level of 8/10 when walking and 7/10 when resting in bed.
The case has been described by Nicoletta Frescos, Adjunct Lecturer, La Trobe University, Victoria, Australia
The wound was examined for signs of infection (including redness, swelling, heat, pain and pus), the wound bed was sloughy, with heavy serous exudate with macerated edges and surrounding erythema (Figure 1). The patient did not report any systemic signs of infection, nausea, chills, or fever.
Part 1: Initial assessment
Vascular assessment: Bilateral dorsalis pedis (DP) and posterior tibial (PT) pulses were palpable. The patient’s Ankle Brachial Pressure Index (APBI) was 0.8 in both legs indicating a mild degree of arterial insufficiency.
Diabetes management: The patients HbA1c recorded one month ago was 6.6%, previously his blood glucose levels have ranged up to 20mmol/L indicating that his diabetes was not always well controlled.
Wound management: Wound hygiene was performed using a surfactant to cleanse the wound bed. The patient experienced pain during the procedure (procedural pain); therefore, wound debridement was not undertaken at the first visit. Post cleansing the wound tissue type showed 20% granulation and 80% slough. The edges were calloused, punched out and inflamed.
Further reading: Holistic Management of Wound-Related Pain
Additionally, topical analgesic and local anaesthetics have been shown to reduce procedural pain as a result of wound dressing changes and debridement. Application of local anaesthetic cream to the wound for 20 minutes prior to undertaking wound procedures can reduce wound related procedural pain.
The Short Form McGill questionnaire, has word descriptors that can assist in differentiating neuropathic pain, nociceptive pain and anticipatory pain. (TODO: idk where this goes, the original doc is incredibly confusing)
The Community Nurse spoke with the GP to request further investigations including: Full blood count, and x-ray of the foot to determine presence of osteomyelitis or other infection. A wound swab was obtained (post wound cleansing) and systemic antibiotics were prescribed whilst awaiting the results of the wound swab to determine culture and sensitivity.
The nurse recommended that the patient off-load their heel in bed using a pillow under the left calf or a bed wedge to lift the heel off the bed. A referral was made to a podiatrist for conservative wound debridement and off-loading devices. Education on diabetes lifestyle modifications was also provided for example smoking cessation, diet, exercise and glucose control.
Part 2: Week 2
The patient reported only mild improvement to his pain. The results of his investigations showed presence of local infection. His foot X-ray showed gas within the soft tissue overlying the calcaneum indicating an infection however no osteomyelitis or bony sclerosis or osteolysis was present (Figure 2). Broad spectrum antibiotics were prescribed.
Conservative wound and peri-wound debridement was performed by a podiatrist. A non-bordered, silicone-based dressing was used to reduce the risk of trauma to the wound bed and surrounding skin and an absorbent secondary dressing was also used to manage the exudate.
Further reading: Explained: MARSI (Medical Adhesive-Related Skin Injury) – Wounds UK and
Best Practice Recommendations for Prevention and Management of Periwound Skin Complications – Wounds International
Vascular assessment: a further vascular assessment was undertaken using a handheld doppler. There was an audible normal (triphasic) DP pulse for the left foot, but the PT pulse was weak, and the signal was reduced (biphasic). The patients toe pressure was L/1st 64 mmHg. As the DP and PT were palpable and the toe pressures were within normal limits this indicated there was still sufficient perfusion.
Neurological assessment: a Semmes-Weinstein filament was used to assess sensation. This showed reduced sensation on both feet. There was the potential for loss of protective sensation.
Further Reading: Prevention guideline (2023 update) – IWGDF Guidelines
Part 3: Week 3
The patient was concerned about his foot pain at night and felt his wound pain was becoming worse. His presenting symptoms of numbness and paraesthesia were consistent with neuropathy. He was prescribed a weak opioid (codeine) which is indicated for neuropathic pain.
Part 4: Week 4
The patient reported that his foot pain was much better at night which has also improved his sleep. The wound was also less painful, and the exudate was now minimal (Figure 3).
Management: His maintenance treatment included atraumatic antimicrobial dressings with off-loading provided by all-purpose wound boots*. He continued to be seen by the podiatrist for regular debridement and off-loading.
*The all-purpose wound boot is a temporary boot that keeps dressing dry and accommodates bulky dressings and off-loading using felt padding and/or insoles. It has a rocker sole which also helps to reduce plantar pressures from under the forefoot and the heel when ambulating. The shoe has adjustable velcro straps to reduce heel slippage and eliminate friction, making them a common and affordable temporary off-loading shoe to assist in wound healing.
Further reading: analgesic stewardship
Summary
This case study highlights the complexity of diabetic foot disease and how peripheral diabetic neuropathy complicates and can mask the cause of wound related pain.
It is important to undertake appropriate assessments and investigations to assist in differential diagnoses to determine the underlying aetiology of wound related pain.
A multidisciplinary team approach to mitigate pain and reduce risk factors is strongly recommended.