- Consider the possibility of infection occurring in any foot wound in a patient with diabetes (SR-L).
Note: Evidence of infection generally includes classical signs of inflammation (redness, warmth, swelling, tenderness or pain) or purulent secretions, but may also include additional or secondary signs (eg, nonpurulent secretions, friable or discolored granulation tissue, undermining of wound edges, foul odor) (SR-L).
- Select and routinely use a validated classification system, such as that developed by the International Working Group on the Diabetic Foot (IWGDF)—abbreviated with the acronym PEDIS—or IDSA (Table 3), to classify infections and to help define the mix of types and severity of their cases and their outcomes (SR-H).
- The DFI (diabetic foot infection) Wound Score (Table 4) may provide additional quantitative discrimination for research purposes (WR-L).
- Other validated diabetic foot classification schemes have limited value for infection, as they describe only its presence or absence (MR-L).
- Evaluate a diabetic patient presenting with a foot wound at 3 levels:
- The patient as a whole
- The affected foot or limb
- The infected wound (SR-L)
- Diagnose infection based on the presence of at least two classic symptoms or signs of inflammation (erythema, warmth, tenderness, pain, or induration) or purulent secretions. Then document and classify the severity of the infection based on its extent and depth and the presence of any systemic findings of infection (SR-L).
- Be aware of factors that increase the risk for DFI and especially consider infection when they are present. These include:
- A wound for which the probe to bone (PTB) test is positive
- An ulceration present for > 30 days
- A history of recurrent foot ulcers
- A traumatic foot wound
- The presence of peripheral vascular disease in the affected limb
- A previous lower extremity amputation
- Loss of protective sensation
- The presence of renal insufficiency
- A history of walking barefoot (SR-L)
- Assess the affected limb and foot for arterial ischemia (SR-M), venous insufficiency, presence of protective sensation and for biomechanical problems (SR-L).
Table 1. Interpretation of the Results of Ankle-Brachial Index Measurement
Ankle-Brachial Index (ABI)a and Interpretation
- > 1.30
- Poorly compressible vessels, arterial calcification
- Mild arterial obstruction
- Moderate arterial obstruction
- < 0.40
- Severe arterial obstruction
a Obtained by measuring the systolic blood pressure (using a properly sized sphygmomanometer) in the ankle divided by that in the brachial artery. The presence of arterial calcification can lead to an overestimate in the index.
- For both outpatients and inpatients with a DFI, provide a well-coordinated approach by those with expertise in a variety of specialties, preferably by a multidisciplinary diabetic foot care team (SR-M).
Note: Where such a team is not yet available, the primary treating clinician should coordinate care among consulting specialists.
- Diabetic foot care teams can include (or should have ready access to) specialists in various fields. Patients with a DFI may especially benefit from consultation with an infectious disease or clinical microbiology specialist and a surgeon with experience and interest in managing DFIs (SR-L).
- Clinicians without adequate training in wound debridement should seek consultation from those more qualified for this task, especially when extensive procedures are required (SR-L).
- If there is clinical or imaging evidence of significant ischemia in an infected limb, consult a vascular surgeon for consideration of revascularization (SR-M).
- Clinicians unfamiliar with pressure off-loading or special dressing techniques should consult foot or wound care specialists when these are required (SR-L).
- In communities with inadequate access to consultation from specialists, consider devising systems (eg, telemedicine) to ensure state-of-the-art patient management (SR-L).
- All patients with a severe infection, selected patients with a moderate infection with complicating features (eg, severe peripheral arterial disease or lack of home support), and any patient unable to comply with the required outpatient treatment regimen for psychological or social reasons, should be hospitalized initially. Patients who do not meet any of these criteria, but are failing to improve with outpatient therapy, may also need to be hospitalized (SR-L).
- Prior to being discharged a patient with a DFI should (SR-L):
- Be clinically stable
- Have had any urgently needed surgery performed
- Have achieved acceptable glycemic control
- Be able to manage (alone or with help) at the designated discharge location
- Have a well-defined plan that includes:
- An appropriate antibiotic regimen to which he/she will adhere
- An off-loading scheme (if needed)
- Specific wound care instructions
- Appropriate outpatient follow-up
- For clinically uninfected wounds, do NOT collect a specimen for culture (SR-L).
- For infected wounds, send appropriately obtained specimens for culture prior to starting empirical antibiotic therapy, if possible (SR-L). Note: Cultures may be unnecessary for a mild infection in a patient who has not recently received antibiotic therapy (SR-L).
- Specimens for culture should be from deep tissue, obtained by biopsy or curettage and after the wound has been cleansed and debrided. Avoid swab specimens, especially of inadequately debrided wounds, since they provide less accurate results (SR-M).
- All patients presenting with a new DFI should have plain radiographs of the affected foot to look for bony abnormalities (deformity, destruction) as well as for soft tissue gas and radio-opaque foreign bodies (SR-M).
- Magnetic resonance imaging (MRI) is the study of choice for patients who require further (ie, more sensitive or specific) imaging, particularly when soft tissue abscess is suspected or the diagnosis of osteomyelitis remains uncertain (SR-M).
- When MRI is unavailable or contraindicated, consider the combination of a radionuclide bone scan and a labeled white blood cell scan as the best alternative (WR-L).