Diabetes is one of the commonest health problems in the world (Alamdari et al, 2017). Globally, 382 million people were affected with diabetes in 2013; this is expected to rise to 592 million by 2035 (Guariguata et al, 2014). In Iran, approximately 4.5 million people had diabetes in 2011, and this number is predicted to reach 9.2 million people by 2030 (Javanbakht et al, 2015).
Diabetic foot ulcer (DFU) is one of the most devastating and costly complications of diabetes (Rice et al, 2013; Zhang et al, 2014). The lifetime risk of a person with diabetes developing a DFU is estimated to be 10–25% (Zhang et al, 2014). The healing process is impaired in people with diabetes, because of intrinsic factors, such as neuropathy and vascular complications, and extrinsic factors, such as wound infection, excessive pressure at the site and callus formation (Catrina and Zheng, 2016). If DFUs do not heal, this often leads to lower extremity amputations (Yazdanpanah et al, 2015). The incidence of non-traumatic lower extremity amputations in people with diabetic foot ulcers has been reported to be 40–70% (Zhang et al, 2014).
The main treatments for DFUs include wound debridement, revascularisation, pressure offloading and infection management. Newer treatment strategies include extracellular matrix proteins, growth factors, negative-pressure wound therapy (NPWT) and stem cell-based therapies. (Baltzis et al, 2014).
Because there is a high prevalence of multi-drug resistant infection in DFUs (Perim et al, 2015), combination therapies are recommended to support effective and reliable DFU treatment (Futrega et al, 2014).
NPWT is a recently developed therapeutic method that promotes wound healing by reducing tissue oedema, increasing local blood flow, preventing bacterial growth, promoting cell hyperplasia and eliminating exudates and proinflammatory cytokines (Zhang et al, 2014).
This article describes a case of a patient who was successfully treated using NPWT along with antibiotic therapy.
Case report
A 51-year-old man with a history of 17 years of uncontrolled type 2 diabetes was referred to Imam Khomeini hospital in Urmia, West Azerbaijan Province, in 2018. He had a history of hepatitis B and end-stage kidney disease. He has been on haemodialysis three times a week since 2015.
His chief complaint was a non-healing wound in the left heel and uncontrollable fever despite taking oral antibiotics. He had developed a deep ulcer to the calcaneus of his left foot, which was 12x7cm in size and infected with multi-drug-resistant Staphylococcus aureus.
His wound had resulted from an injury sustained after an accidental burn from a heater in 2015. It had been treated with routine care (saline dressing and occasionally antibiotics) over the past 3 years. He had been taking regular and NPH insulin for 9 years. After admission, because of his lab results (fasting blood sugar=165 mg/dl; 2–hour postprandial blood-sugar=381 mg/dl; HbA1c=7.4; blood urea nitrogen=118.4 mg/dl; creatinine =9.15 mg/dl), his attending physician adjusted his medications to improve diabetes control and stabilise his condition.
The patient was referred to the orthopaedic medical group and a wound manager for further evaluation and treatment. The orthopaedic specialist recommended amputation. However, the wound manager's recommendation was NPWT after the patient had been discharged from hospital. His medical history and clinical examination showed he had no history of underlying chronic lung and cardiovascular disease, which made him a good case for treatment.
After osteomyelitis was ruled out and the adequacy of the blood supply to the affected area had been confirmed, treatment was started. An antibiogram study revealed multi-drug resistant Staphylococcus aureus. While in hospital, the patient received sharp debridement in the operating room and routine wound care twice a day along with intravenous antibiotic treatment (clindamycin 600 mg every 8 hours and Ciprofloxacin 200 mg every 12 hours).
The patient was discharged from hospital with a 2–week course of oral antibiotics. The wound manager visited the patient at home and found he was clinically stable with a wound in his left foot (Figure 1). With the patient's consent to treatment, a decision was made to apply NPWT along with oral antibiotic treatment (Figure 2). The patient also signed a form giving consent to this study. He received 20 sessions of NPWT, each lasting 3 days. The foam dressing was replaced after each NPWT session.
Intermittent NPWT with negative pressure set at -125 mmHg was used. The vacuum therapy device used was the Vacumed VAC (Fanavar Pooya Sepahan Engineering Company) (Figure 3). After finishing NPWT, his wound was irrigated with saline and mechanical debridement carried out. Silver foam dressings were then applied for 30 days to facilitate and accelerate the wound healing (Table 1).
| Month 1 | Month 2 | Month 3 |
|---|---|---|
| Negative pressure wound therapy (NPWT) with foam dressing change every 72 hours | NPWT with foam dressing change every 72 hours | Saline irrigation, mechanical debridement and silver foam dressing |
Offloading is crucial for DFU healing. The patient used offloading devices such as crutches and a wheelchair throughout the course of treatment. The patient's wound healed progressively. After receiving NPWT and silver foam dressing for 3 months, the patient was discharged in a good condition (Figure 4).
Discussion
Diabetic foot ulcer treatment is one of the most challenging issues in healthcare systems worldwide (Braun et al, 2014; Frykberg and Banks, 2015). Wound healing is impaired in patients with diabetes because of changes in the microcirculation (Pan et al, 2017). Even with appropriate, standard wound care, only 24% and 30% of DFUs heal at 12 and 20 weeks respectively (Margolis et al, 1999).
All infected wounds should be treated with antibiotics. However, wound care provided is often insufficient (Pan et al, 2017). The patient in this study had had uncontrolled blood sugar levels for 3 years, and likely developed a multi-drug resistant infection because of inappropriate use and overuse of antibiotics. He was also restricted over taking antibiotic drugs because of end-stage kidney disease.
DFUs arise as a result of multiple biochemical deficiencies. Therefore, a single treatment strategy is unlikely to have been effective in this patient. New DFU treatment strategies must be combined to address underlying pathological conditions effectively and facilitate DFU healing (Futrega et al, 2014). The authors decided to combine wound debridement and oral antibiotic treatment with NPWT to facilitate the suction of pus and necrotic tissue to accelerate wound healing and improve infection control.
In this case, wound irrigation and debridement were performed first to clean the infected ulcer. NPWT was then applied and oral antibiotics administered to promote wound healing. This treatment strategy effectively resolved a non-healing DFU that was infected with multi-drug resistant Staphylococcus aureus.
A study by Potula (2017) showed NPWT was more effective than conventional wound care regarding rates and times of healing. Liu et al (2017) conducted a systematic review and reported that NPWT was a safe, effective and affordable way to treat DFUs. Other recent studies have also shown that NPWT is a safe and effective method to accelerate healing of DFUs (Zhang et al, 2014; Frykberg and Banks, 2015).
Conclusion
A combination of standard wound care with innovative treatment strategies such as NPWT can be useful in treating non-healing DFUs that are resistant to conventional treatment and can reduce healing time.
The research team would encourage medical and wound care teams to use a combination of methods to accelerate recovery, shorten the treatment period and reduce costs to patients and healthcare systems.