What is the diagnosis and initial treatment for a patient with diabetes (diabetes mellitus) and hypertension who experiences nocturnal numbness and pain in the right foot, relieved by hanging the leg over the side of the bed?

Diagnosis: Chronic Limb-Threatening Ischemia (Critical Limb Ischemia)

This patient has chronic limb-threatening ischemia (CLTI), not diabetic neuropathy, and requires urgent vascular surgery referral for revascularization assessment to prevent limb loss. 1

Key Diagnostic Features

The clinical presentation is pathognomonic for severe peripheral arterial disease:

• Nocturnal rest pain within 20 minutes of lying flat indicates inadequate perfusion that worsens when gravity no longer assists blood flow to the foot 1
• Relief by dependency (hanging the leg over the bed) temporarily improves perfusion through gravitational assistance—this positional relief is a classic sign of severe peripheral ischemia 2, 1
• Dependent rubor (the foot becoming "quite red" when dependent) confirms critical limb ischemia 1

Critical Distinction from Diabetic Neuropathy

This is NOT diabetic neuropathy despite the patient having diabetes. Key differentiating features:

• Painful diabetic neuropathy is invariably bilateral and symmetrical—unilateral symptoms should prompt investigation for vascular disease 3, 4
• Neuropathic pain is characteristically worse at night but does not have positional relief 2
• The specific relief pattern (hanging leg over bed) and dependent rubor are pathognomonic for ischemia, not neuropathy 1

Immediate Diagnostic Workup

Obtain ankle-brachial index (ABI) immediately to confirm diagnosis and assess severity: 1

• ABI <0.9 indicates peripheral arterial disease 2, 1
• ABI <0.40 or ankle pressure <50 mmHg confirms CLTI and indicates severely impaired circulation requiring urgent intervention 2, 1
• Toe pressure <30 mmHg or TcPO₂ <30 mmHg also confirms CLTI 2

Initial Treatment: Urgent Management Protocol

1. Immediate Medical Therapy

• Initiate antiplatelet therapy with aspirin 75-325 mg daily if not already prescribed 1
• Provide adequate pain control—morphine may be necessary for rest pain 1
• Start or optimize statin therapy targeting LDL-C <55 mg/dL (<1.4 mmol/L) 1

2. Urgent Vascular Surgery Referral

Revascularization should be attempted without delay when anatomically possible—the goal is limb salvage, not just symptom improvement 2, 1

• Endovascular intervention is typically first-line for anatomically suitable lesions 1
• Surgical bypass may be necessary for complex disease 1

3. Risk Factor Optimization

• Optimize glycemic control (target HbA1c <7%)—particularly important in diabetes for improved limb-related outcomes, including lower rates of major amputation 2, 1
• Target blood pressure <130/80 mmHg in this diabetic patient with PAD 1
• ACE inhibitors are recommended to reduce cardiovascular events in symptomatic PAD 1
• Beta-blockers are safe and effective in PAD and do not adversely affect walking capacity 1

4. Immediate Foot Protection

• Implement comprehensive foot protection measures immediately: daily foot inspection by patient and frequent examination by clinician 1
• Proper footwear—never walk barefoot, in socks only, or thin-soled slippers 1
• Urgent attention to any skin lesions or ulcerations 1

5. Wound Care and Infection Management

• Proper wound care must be started immediately if any tissue breakdown is present 2
• Use adapted footwear and treat concomitant infection 2
• Wound care specialists should be involved if tissue loss develops 1

Common Pitfall to Avoid

The most critical error would be misdiagnosing this as diabetic neuropathy and treating with gabapentinoids or other neuropathic pain medications while missing the vascular emergency. The unilateral presentation, positional relief, and dependent rubor are red flags that distinguish this from neuropathy. 3, 4 Delayed revascularization in CLTI significantly increases amputation risk. 2