How should I evaluate and manage suspected plantar neuropathy in an adult with obesity (BMI 38) and poorly controlled type 2 diabetes (daytime glucose up to 150 mg/dL, nighttime 110–120 mg/dL)?

Evaluation and Management of Suspected Plantar Neuropathy in Obesity with Uncontrolled Type 2 Diabetes

Your patient requires immediate optimization of glycemic control with metformin initiation (if not contraindicated) targeting HbA1c <7%, combined with structured weight loss intervention, and pregabalin 50 mg three times daily for neuropathic pain if present, while conducting a comprehensive neuropathy assessment at the current visit. 1, 2, 3, 4

Immediate Diagnostic Evaluation

Clinical Examination Required Today

Perform a structured neurological examination specifically designed to identify loss of protective sensation (LOPS), which is the critical finding that determines foot ulceration risk 1, 5:

• 10-g monofilament testing at multiple plantar sites (hallux, metatarsal heads) - this is the single most important test 1, 5
• 128-Hz tuning fork for vibration sensation on the great toe and medial malleolus to assess large-fiber function 1, 5
• Pinprick or temperature sensation testing to evaluate small-fiber function 1
• Ankle reflex assessment bilaterally 1
• Visual inspection for skin breakdown, calluses, erythema, warmth, deformities (hammertoes, bunions, prominent metatarsal heads, Charcot changes) 1, 5
• Palpation of pedal pulses (dorsalis pedis and posterior tibial) to screen for peripheral arterial disease 1

Critical diagnostic rule: Two or more abnormal tests confirm LOPS; two normal tests (with no abnormal findings) rule out LOPS 1. One abnormal test suggests LOPS and warrants heightened surveillance 1.

Exclude Charcot Neuroarthropathy

Given the obesity and neuropathy, you must actively exclude active Charcot neuroarthropathy if you find 1:

• Temperature difference >2°C between feet (use infrared thermometry if available, comparing identical anatomic points) 1
• Unilateral warmth, erythema, or edema with intact skin 1
• If suspected: Obtain bilateral weight-bearing plain X-rays (AP, medial oblique, lateral views of foot; AP, mortise, lateral of ankle) immediately and initiate knee-high immobilization while awaiting imaging 1
• If X-rays are normal but suspicion remains high: Obtain MRI to exclude early Charcot changes 1

Laboratory Assessment

Order the following to establish baseline and guide treatment 1, 3:

• HbA1c (likely elevated given daytime glucose 150 mg/dL) 3
• Comprehensive metabolic panel including creatinine to calculate creatinine clearance (essential for pregabalin dosing) 4
• Lipid panel (obesity and diabetes increase cardiovascular risk) 3
• TSH, vitamin B12, serum protein electrophoresis only if clinical features are atypical for diabetic neuropathy 1

Do NOT order CRP, ESR, or alkaline phosphatase for neuropathy diagnosis - these are not useful 1.

Glycemic Control Strategy

Target Goals

Your patient's current glucose control is inadequate 3:

• Target HbA1c: <7% (or <6.5% if achievable without hypoglycemia in this 50-year-old) 1, 3
• Fasting glucose: 80-130 mg/dL (currently acceptable at 110-120 mg/dL) 3
• Daytime/postprandial glucose: <180 mg/dL (currently 150 mg/dL is borderline but suboptimal) 3

Pharmacologic Intervention

Initiate metformin immediately unless contraindicated by renal dysfunction (creatinine clearance <30 mL/min) 3:

• Start 500 mg once or twice daily with meals, titrate weekly to 1000 mg twice daily as tolerated 3
• Metformin is equally effective in obese and lean patients and is weight-neutral or promotes modest weight loss 1

Critical warning about rapid glycemic improvement: Avoid precipitous glucose lowering, as this can trigger treatment-induced neuropathy of diabetes (TIND), causing acute worsening of neuropathic symptoms 2, 6. Gradual titration over weeks is safer than aggressive immediate control 6.

Weight Management - Non-Negotiable Priority

Mandate structured lifestyle intervention modeled on the Diabetes Prevention Program 7, 8:

• Weight loss goal: 5-7% reduction (approximately 5-7 kg for BMI 38) 7
• Exercise prescription: 150 minutes/week of moderate-intensity aerobic activity (55-69% heart rate reserve or 12-13 on Borg scale), distributed over at least 3 days with no more than 2 consecutive rest days 3
• Resistance training: 2-3 sessions/week on non-consecutive days 3

Reassurance about exercise safety: Moderate-intensity walking does NOT increase foot ulcer risk even with established peripheral neuropathy, provided proper footwear is used 5, 3. Do not restrict exercise unless there is complete loss of protective sensation with active ulceration 3.

Weight loss and exercise directly reduce neuropathic pain independent of glucose control 7, 9.

Neuropathic Pain Management

If Patient Has Current Neuropathic Pain

Initiate pregabalin immediately 2, 3, 4:

• Starting dose: 50 mg three times daily (150 mg/day) 4
• Titration: Increase to 100 mg three times daily (300 mg/day) within 1 week based on pain relief and tolerability 4
• Maximum dose: 300 mg/day for diabetic peripheral neuropathy (doses above this show no additional benefit and worse tolerability) 4
• Renal adjustment required: Reduce dose if creatinine clearance <60 mL/min 4

Alternative first-line options if pregabalin is not tolerated 1, 2, 3:

• Duloxetine 60 mg daily (can increase to 120 mg) 1
• Gabapentin 300 mg three times daily, titrated to 1200 mg three times daily as needed 1, 2

Second-line options for inadequate response 1:

• Tricyclic antidepressants: Amitriptyline or nortriptyline 10-75 mg at bedtime (use caution in obesity due to cardiovascular effects) 1

Avoid opioids for neuropathic pain management 3.

Foot Care Protocol - Prevent Amputation

Patient Education (Mandatory at This Visit)

Educate on the following specific behaviors 1, 5:

• Daily foot self-examination using a mirror to inspect plantar surfaces for cuts, blisters, redness, or calluses 2, 5, 3
• Never walk barefoot, even indoors 3
• Proper footwear at all times: Well-fitted walking shoes or athletic shoes that cushion and redistribute plantar pressure 1
• Immediate reporting of any foot lesions, warmth, redness, or swelling 1, 5

Footwear Prescription

Based on examination findings 1:

• If LOPS without deformities: Well-fitted athletic or walking shoes with cushioning 1
• If bony deformities present (hammertoes, bunions, prominent metatarsal heads): Extra-wide or depth shoes 1
• If severe deformities or Charcot foot: Custom-molded shoes 1

Follow-Up Schedule

• Every 3 months until HbA1c at goal, then every 6 months if stable 3
• Comprehensive foot examination at every visit 3
• Annual 10-g monofilament testing once neuropathy is established 5

Common Pitfalls to Avoid

1. Do not aggressively lower glucose too rapidly - this can precipitate acute painful neuropathy (TIND) 2, 6
2. Do not use subtherapeutic pregabalin doses (e.g., 75 mg/day) - inadequate pain control leads to poor adherence 3
3. Do not restrict exercise based on neuropathy diagnosis alone - exercise is beneficial and safe with proper footwear 5, 3
4. Do not miss Charcot neuroarthropathy - any acute unilateral warmth/swelling requires immediate immobilization and imaging 1
5. Do not rely on patient symptoms alone - 50% of neuropathy is asymptomatic, making objective testing essential 1, 10