What is the assessment and treatment for a man in his late 50s with worsening peripheral neuropathy of bilateral feet?

Assessment and Treatment of Worsening Bilateral Foot Neuropathy in a Man in His Late 50s

This patient requires immediate comprehensive diabetic foot screening, optimization of glycemic control if diabetic, and initiation of duloxetine 60 mg daily for neuropathic pain, combined with structured offloading footwear to prevent ulceration.

Initial Clinical Assessment

Neurological Examination

Perform a focused examination to confirm loss of protective sensation (LOPS) using at least two of the following tests 1:

• 10-g monofilament testing (most essential screening tool) 1
• 128-Hz tuning fork for vibration sense 1, 2
• Pinprick sensation testing 1
• Ankle reflex assessment 1
• One or more abnormal tests confirms LOPS, while two normal tests (with no abnormal findings) rules it out 1

Vascular Assessment

Critical to distinguish neuropathy from ischemia, as management differs substantially 1, 2:

• Palpate all four pedal pulses (dorsalis pedis and posterior tibial bilaterally), rating as 0 (absent), 1 (diminished), 2 (normal), or 3 (bounding) 2
• Presence of all four pulses makes peripheral artery disease unlikely 2
• Obtain ankle-brachial index (ABI) if pulses are diminished or absent, as many PAD patients are asymptomatic 1, 2
• If ABI >1.4 (suggesting non-compressible vessels from medial arterial calcification common in diabetes), measure toe-brachial index (TBI); TBI ≤0.70 indicates PAD 2
• Refer patients with significant symptoms or positive ABI/TBI for vascular assessment 1

Foot Structure and Skin Integrity

Examine in a well-lit room for 1:

• Callus formation, erythema, or warmth (indicates areas of increased pressure with impending breakdown) 1
• Bony deformities (hammertoes, prominent metatarsal heads, bunions, Charcot foot, pes planus) 1
• Skin breakdown or ulceration (requires immediate podiatry referral) 3
• Limitation in joint mobility and gait abnormalities 1

Symptom Characterization

Document specific symptoms using a 0-10 numerical scale 4, 3:

• Pain intensity, quality (burning, lancinating, shooting) 4
• Numbness and tingling distribution (typically "stocking-glove" pattern) 4, 2
• New weakness or balance problems (indicates proprioceptive loss requiring urgent intervention) 3
• History of falls or knee buckling (significant functional impairment) 3

Autonomic Neuropathy Screening

Check for 3:

• Orthostatic hypotension (measure blood pressure supine and after 3 minutes standing) 3
• Resting tachycardia 3
• These findings indicate autonomic involvement and require cardiac evaluation before initiating exercise programs 3

Laboratory Workup

Essential Initial Tests

Order the following to identify treatable causes 4, 5, 6:

• Fasting blood glucose and HbA1c (diabetes is the most common cause) 4, 5, 6
• Vitamin B12 level with methylmalonic acid and homocysteine (identifies reversible deficiency) 4, 3, 6
• Thyroid-stimulating hormone (TSH) 4, 5, 6
• Complete blood count and comprehensive metabolic profile 5, 6
• Serum protein electrophoresis with immunofixation (screens for monoclonal gammopathy) 6
• Erythrocyte sedimentation rate 5

Additional Testing if Indicated

Consider based on clinical context 4, 5:

• Hepatitis B, C, and HIV testing if risk factors present 4
• Medication review for neurotoxic agents (metronidazole, chemotherapy, certain antibiotics) 3

Risk Stratification and Follow-Up Frequency

Use the International Working Group on the Diabetic Foot (IWGDF) Risk Classification System 2:

• Category 1 (peripheral neuropathy alone): Examine every 6 months 2
• Category 2 (neuropathy with PAD and/or foot deformity): Examine every 3-6 months 2
• Category 3 (neuropathy with history of ulcer or amputation): Examine every 1-3 months 2

Given this patient's "worsening" symptoms, he likely falls into Category 1 or 2, requiring more frequent monitoring than annual screening 2.

Disease-Modifying Treatment

Glycemic Control (If Diabetic)

Optimize glucose control aggressively but carefully 4, 2, 3:

• Target individualized HbA1c goals based on patient factors 4, 2
• Avoid dropping HbA1c >3% rapidly, as this can cause treatment-induced neuropathy with paradoxical worsening 1
• Strict glucose control prevents progression but does not reverse established neuropathy 4, 2

Cardiovascular Risk Factor Management

Address aggressively as these contribute to neuropathy progression 4, 2, 3:

• Optimize blood pressure control 4, 2, 3
• Manage hyperlipidemia 4, 2
• Smoking cessation if applicable 1

Nutritional Deficiency Correction

• Correct vitamin B12 deficiency if identified 2, 3

Symptomatic Pain Management

First-Line Pharmacological Treatment

Duloxetine 60 mg once daily is the preferred first-line agent 4, 2:

• Can increase to 120 mg daily if needed for additional benefit 4, 2
• Has the strongest evidence base for diabetic peripheral neuropathy 4
• Also effective for chemotherapy-induced neuropathy 4

Alternative First-Line Options

If duloxetine is contraindicated or not tolerated 4, 3:

• Pregabalin (dosing not specified in guidelines but typically 150-600 mg/day) 4, 3
• Gabapentin (300-2400 mg/day, titrate to highest tolerated dose) 1, 4, 3

Second-Line Options

• Tricyclic antidepressants (amitriptyline 25-75 mg/day) are effective but have significant anticholinergic side effects, making them less suitable for elderly patients 4

Non-Pharmacological Interventions

Recommend as adjunctive therapy 4:

• Regular physical activity 4
• Acupuncture 4
• Cognitive behavioral therapy 4
• Structured physical therapy focusing on quadriceps strengthening and balance training to compensate for proprioceptive deficits and prevent falls 3

Footwear and Offloading

For Neuropathy with Evidence of Increased Plantar Pressure

Patients with erythema, warmth, callus, or measured pressure require 1:

• Well-fitted walking shoes or athletic shoes that cushion feet and redistribute pressure 1
• Callus debridement by a foot care specialist with scalpel 1

For Bony Deformities

• Extra wide or deep shoes for hammertoes, prominent metatarsal heads, or bunions 1
• Custom-molded shoes for extreme deformities (e.g., Charcot foot) that cannot be accommodated with standard footwear 1

Patient Education

Instruct all at-risk patients on 1, 2:

• Daily foot inspection (use mirror or have family member assist if visual impairment present) 1, 2
• Wash feet daily and dry thoroughly, especially between toes 2
• Never walk barefoot, even indoors 2
• Wear seamless socks 2
• Inspect inside shoes before wearing 2
• Substitute other sensory modalities (hand palpation, visual inspection) for surveillance since protective sensation is lost 1
• Wear loose-fitting shoes, roomy cotton socks, and padded slippers 1

Assess patient's physical ability and cognitive capacity to perform foot care; if impaired, involve family members 1.

Specialist Referral Indications

Immediate Podiatry/Wound Care Referral

• Any foot ulcer, significant callus, or severe bony deformity 3
• History of prior ulcer or amputation 1

Multidisciplinary Foot Care Team

Refer patients with 1:

• High-risk feet (structural abnormalities, loss of protective sensation) 1
• History of smoking with neuropathy 1

Neurology Referral

Consider if 6:

• Initial evaluation is inconclusive
• Need for electrodiagnostic studies or nerve biopsy
• Rapidly progressive symptoms
• Atypical presentation

Common Pitfalls to Avoid

• Do not assume all foot symptoms are neuropathic—always assess vascular status, as PAD requires different management 1, 2
• Do not rapidly reduce HbA1c >3% in patients with longstanding hyperglycemia, as this can paradoxically worsen neuropathy 1
• Do not rely on patient-reported foot inspection—directly examine feet at every visit in patients with neuropathy 1
• Do not overlook autonomic neuropathy—check orthostatic vital signs and require cardiac clearance before exercise programs 3
• Do not prescribe removable offloading devices without emphasizing compliance—non-removable devices are superior for healing but may not be appropriate initially if infection requires frequent wound assessment 1