From the Guidelines
This patient requires urgent evaluation for a diabetic foot infection, specifically cellulitis or possible deep tissue infection, and should be immediately referred to an emergency department or urgent care center for assessment. The presence of edema and erythema in the foot, despite the absence of pain due to diabetic neuropathy, is concerning and warrants prompt attention 1. Initial management will likely include blood tests (complete blood count, inflammatory markers, blood cultures), imaging (X-ray to rule out osteomyelitis, possibly MRI), and empiric broad-spectrum antibiotic therapy. A reasonable initial antibiotic regimen would be intravenous piperacillin-tazobactam 4.5g every 8 hours or ertapenem 1g daily, potentially with vancomycin 15-20mg/kg every 12 hours if MRSA is suspected 1.
Some key points to consider in the evaluation and management of this patient include:
- The classification of diabetic foot infections, as outlined by the International Working Group on the Diabetic Foot (IWGDF) and the Infectious Diseases Society of America (IDSA), which defines infection based on the presence of local signs and symptoms, such as erythema, swelling, and purulent discharge 1.
- The importance of considering the patient's underlying risk factors, such as peripheral neuropathy and peripheral arterial disease (PAD), which can increase the risk of infection and poor outcomes 1.
- The need for a multidisciplinary approach to management, including endocrinology, infectious disease, podiatry, and vascular surgery, to prevent recurrence and limb loss 1.
After initial stabilization, the patient will need comprehensive diabetic foot care, including:
- Offloading devices to reduce pressure on the affected foot
- Regular wound checks to monitor for signs of infection or healing
- Glucose control optimization, with a target HbA1c <7%
- Education on daily foot inspection to identify early signs of infection or other complications 1.
Overall, the goal of management is to prevent limb loss and improve quality of life, while also reducing the risk of recurrence and other complications associated with diabetic foot infections 1.
From the Research
Evaluation of Diabetic Foot
The evaluation of a 60-year-old diabetic patient with sudden onset of edema and erythema in the foot, with diabetic neuropathy, but no pain or visible wounds, should include:
- A thorough clinical examination to assess for signs of infection, such as increased rate of signs of inflammation 2
- Non-invasive vascular testing to assess for decreased perfusion, as patients with diabetic foot ulcer and decreased perfusion may not have rest pain or claudication 2, 3
- Imaging studies, such as plain radiographs or magnetic resonance imaging, to diagnose or better define deep, soft tissue purulent collections and to detect pathological findings in bone 4, 2
Management of Diabetic Foot
The management of the diabetic foot should include:
- Empiric antibiotic therapy, with the initial antimicrobial treatment and duration of treatment being empiric 2
- Surgical intervention, ranging from minor (debridement) to major (resection, amputation), as most diabetic foot infections require some surgical intervention 4, 3
- Proper dressing and off-loading of pressure, as well as regular follow-up 4, 2
- Consideration of revascularization, as an ischemic foot may require revascularization to achieve healing 2, 3
- A multidisciplinary approach to foot care, involving a team of specialists, to improve outcomes and reduce the risk of amputation 4, 5, 3
Considerations for Diabetic Neuropathy
The presence of diabetic neuropathy increases the risk of insensitive foot lesions, and regular and thorough examination is necessary to identify patients at risk 6