What is the recommended workup and treatment for a patient with a diabetic ulcer?

Workup of a Diabetic Ulcer

When a diabetic patient presents with a foot ulcer, immediately perform a comprehensive vascular assessment including ankle-brachial index (ABI), toe pressures, and transcutaneous oxygen pressure (TcPO2), recognizing that ABI may be falsely elevated in diabetes due to arterial calcification—making toe pressure and TcPO2 more reliable indicators of perfusion. 1, 2

Initial Clinical Assessment

Ulcer Characterization and Classification

• Document ulcer location, size (by planimetry), depth, and appearance to establish baseline and track healing progress 3, 4
• Classify the ulcer using Wagner or Texas grading systems to guide treatment intensity and prognosis 3
• Probe the wound to bone to assess for osteomyelitis—if the probe reaches bone, assume osteomyelitis is present until proven otherwise 1

Neurological Evaluation

• Perform 10-g Semmes-Weinstein monofilament testing to assess for loss of protective sensation 3
• Test vibration perception and pinprick sensation to comprehensively evaluate neuropathy 3
• Document presence of neuropathic symptoms including pain, burning, or numbness 3

Vascular Assessment (Critical Priority)

This is where most clinicians make critical errors—do not rely solely on ABI in diabetic patients. 1, 2

• Measure toe pressure: Values <30 mmHg indicate critical ischemia requiring urgent revascularization 1, 2
• Measure TcPO2: Values <25-30 mmHg indicate inadequate perfusion for healing 1, 2
• Calculate ABI, but recognize it may be falsely elevated (>1.3) due to arterial calcification in diabetes 1, 2
• Assess for clinical signs of critical ischemia: thick purple skin, dependent rubor, absent pulses, or prolonged capillary refill 1

If toe pressure is <30 mmHg, TcPO2 is <25-30 mmHg, or thick purple skin is present, this is a medical urgency requiring vascular imaging and likely revascularization within 24 hours. 1

Infection Assessment

• Look for clinical signs of infection: purulent drainage, erythema extending >2 cm from wound edge, warmth, induration, or systemic signs (fever, elevated WBC, hyperglycemia) 3, 1
• Classify infection severity as mild (superficial), moderate (deeper structures involved), or severe (systemic toxicity) 3
• Obtain wound cultures before initiating antibiotics, ideally from deep tissue or bone (not superficial swabs) 3
• Order plain radiographs to evaluate for gas in soft tissues or osteomyelitis 3

Structural and Biomechanical Evaluation

• Examine for foot deformities: hammer toes, claw toes, hallux valgus, prominent metatarsal heads, Charcot changes 3
• Assess for pre-ulcerative signs: callus formation, blisters, nail abnormalities, skin fissures 3, 5
• Evaluate current footwear for appropriateness and pressure points 3

Laboratory and Imaging Workup

Essential Laboratory Tests

• HbA1c to assess glycemic control 3
• Complete blood count to evaluate for systemic infection 1
• Inflammatory markers (ESR, CRP) if osteomyelitis is suspected 3
• Renal function (creatinine, eGFR) as this affects healing and medication choices 3

Vascular Imaging (When Indicated)

Obtain urgent vascular imaging if toe pressure <30 mmHg, TcPO2 <25-30 mmHg, or clinical signs of critical ischemia are present. 1

• Options include: color Doppler ultrasound, CT angiography, MR angiography, or digital subtraction angiography 1
• Imaging must visualize the entire lower extremity arterial tree, including below-the-knee and pedal arteries 1

Bone Imaging (When Osteomyelitis Suspected)

• Plain radiographs are first-line but may be negative early in infection 3
• MRI is the gold standard for diagnosing osteomyelitis if radiographs are inconclusive 3
• Bone biopsy with culture provides definitive diagnosis and guides antibiotic selection 3

Risk Stratification Using IWGDF System

Classify patients using the IWGDF risk stratification to determine follow-up frequency: 3

• IWGDF Risk 0: No neuropathy—screen annually
• IWGDF Risk 1: Neuropathy alone—screen every 6-12 months 3
• IWGDF Risk 2: Neuropathy plus PAD or foot deformity—screen every 3-6 months 3
• IWGDF Risk 3: History of foot ulcer or amputation—screen every 1-3 months 3

Common Pitfalls to Avoid

The most critical error is relying solely on ABI for vascular assessment in diabetic patients—arterial calcification renders this measurement unreliable, potentially missing critical ischemia. 1, 2

The second major pitfall is delaying vascular imaging and revascularization while attempting conservative wound care—ischemic ulcers will not heal without adequate perfusion, regardless of advanced wound therapies applied. 1

Third, failing to recognize purple skin as a medical urgency—this indicates critical ischemia requiring evaluation within 24 hours, not routine outpatient follow-up. 1

Fourth, underestimating infection severity—what appears as mild cellulitis may represent deep space infection or osteomyelitis requiring urgent surgical intervention. 3, 1

Fifth, inadequate debridement—all necrotic tissue and surrounding callus must be removed for healing to occur, and this often requires repeated sharp debridement. 3

Immediate Management Priorities

For Ischemic Ulcers (toe pressure <30 mmHg or TcPO2 <25-30 mmHg)

• Urgent vascular surgery or interventional radiology consultation within 24 hours 1
• Do not waste time with advanced wound therapies (growth factors, skin substitutes, hyperbaric oxygen) before addressing the fundamental perfusion problem 1

For Infected Ulcers

• Mild infection: Oral antibiotics targeting S. aureus and streptococci 3
• Moderate/severe infection: Urgent surgical debridement, broad-spectrum IV antibiotics covering gram-positive, gram-negative, and anaerobic organisms including MRSA 3, 1

For All Ulcers

• Sharp debridement of all necrotic tissue and surrounding callus, repeated as clinically necessary 3
• Strict offloading with non-removable devices (total contact cast or removable cast walker rendered irremovable) for plantar ulcers 3
• Optimize glycemic control targeting HbA1c <7% 3
• Multidisciplinary team involvement including endocrinology, vascular surgery, podiatry, and wound care specialists 3