What are the diagnostic criteria for diabetic foot?

From the Guidelines

The diagnostic criteria for diabetic foot include a comprehensive foot examination with assessment of protective sensation using a 10g monofilament test or 128 Hz tuning fork to detect neuropathy, as well as vascular assessment and wound evaluation, as recommended by the most recent guidelines 1. The diagnostic criteria for diabetic foot are based on a combination of clinical findings and tests. A diabetic foot is diagnosed when a patient with diabetes has foot ulceration, infection, or tissue destruction associated with neurological abnormalities and peripheral arterial disease.

Key Diagnostic Elements

• Comprehensive foot examination with assessment of protective sensation using a 10g monofilament test or 128 Hz tuning fork to detect neuropathy
• Vascular assessment involves checking pedal pulses, ankle-brachial index (ABI), and toe pressures to identify peripheral arterial disease
• Wound evaluation includes measuring size, depth, appearance, and presence of infection using the PEDIS (Perfusion, Extent, Depth, Infection, Sensation) or SINBAD (Site, Ischemia, Neuropathy, Bacterial Infection, Area, Depth) classification systems
• Laboratory tests such as complete blood count, erythrocyte sedimentation rate, C-reactive protein, and wound cultures help assess infection severity
• Imaging studies like plain radiographs, MRI, or bone scans may be needed to detect osteomyelitis or deep tissue infections

Screening Recommendations

• Regular foot screening for all diabetes patients is recommended at least annually, with more frequent assessments for those with risk factors such as previous ulceration, deformities, or peripheral neuropathy, as stated in the guidelines 1
• The International Working Group on the Diabetic Foot (IWGDF) risk stratification system should be used to determine the risk of foot ulceration and guide treatment, as recommended by the most recent guidelines 1

Importance of Early Diagnosis

Early diagnosis is crucial as diabetic foot complications progress rapidly and can lead to amputation if not properly managed.

• The guidelines emphasize the importance of regular foot screening and comprehensive foot examination to identify high-risk conditions and prevent foot ulcers and amputations 1

From the Research

Diagnostic Criteria for Diabetic Foot

The diagnostic criteria for diabetic foot involve a combination of clinical evaluation, laboratory tests, and imaging studies. The following are some of the key diagnostic criteria:

• Clinical evaluation: diagnosis begins with a history and physical examination to identify signs of inflammation, such as redness, warmth, swelling, and purulent discharge 2
• Laboratory tests: serological tests, such as measurement of the erythrocyte sedimentation rate, may be helpful in diagnosing osteomyelitis, but are relatively non-specific 2
• Imaging studies: plain radiographs, computed tomography, magnetic resonance imaging (MRI), and nuclear medicine scintigraphy are commonly used to evaluate the diabetic foot 3, 4, 5
• Diagnostic imaging modalities: multiple diagnostic imaging modalities are available and beneficial for the evaluation of the diabetic foot, including conventional radiography, computed tomography, nuclear medicine scintigraphy, magnetic resonance imaging, ultrasonography, and positron emission tomography 3

Imaging Studies for Diabetic Foot

Imaging studies play a crucial role in the diagnosis of diabetic foot. The following are some of the key imaging studies:

• Plain radiographs: although less sensitive than other imaging modalities, plain radiographs should be the initial procedure for imaging suspected osteomyelitis in the diabetic patient 5
• MRI: MRI offers exquisite anatomical detail, which is invaluable for guiding surgical management, and is useful in diagnosing osteomyelitis and neuroarthropathy 4, 5
• Nuclear medicine scintigraphy: three-phase bone scintigraphy is sensitive but not specific, while labelled leucocyte scintigraphy is valuable for diagnosis and follow-up of pedal osteomyelitis 4
• Computed tomography: computed tomography is useful in evaluating the diabetic foot, especially in cases where MRI is not available or contraindicated 3

Predictors of Amputation and Length of Stay

Several factors can predict amputation and length of stay in diabetic patients with acute foot ulceration, including:

• Baseline levels of acute-phase reactants, such as C-reactive protein (CRP), white blood cells (WBC), and erythrocyte sedimentation rate (ESR) 6
• Wagner grade and infection severity 6
• Glycemic control parameters, such as hemoglobin A1C (HbA1C) and plasma glucose, although these were not found to be significant predictors in one study 6