What is the most likely diagnosis for a patient with worsening leg pain, history of peripheral arterial disease (PAD), hypertension, and type 2 diabetes, with decreased pulses and pain at rest?

Critical Limb Ischemia (CLI)

This patient has progressed to critical limb ischemia (CLI), defined by chronic ischemic rest pain that worsens with leg elevation and has persisted for 2 weeks in the setting of known PAD with severely diminished perfusion. 1

Clinical Reasoning

The diagnosis of CLI is established by the following key features in this patient:

• Rest pain present for 2 weeks duration - CLI requires chronic ischemic rest pain lasting more than 2 weeks, which this patient meets 1, 2
• Pain worsens with leg elevation - Classic for CLI, as gravity-dependent flow is lost when the leg is elevated 1
• Progression from stable claudication - The patient previously walked half a mile before pain, now has continuous pain even at rest, indicating severe deterioration 1
• Absent pedal pulses with Doppler signals only at 200 mmHg cuff pressure - This indicates severely reduced ankle pressures, likely <50 mmHg, which is diagnostic of CLI 1
• Multiple atherosclerotic risk factors - Diabetes, hypertension, and established PAD with widespread vascular disease (carotid bruits, subclavian bruits, femoral bruits) 1

Diagnostic Confirmation Required

Immediate ABI measurement is mandatory to objectively confirm CLI and assess severity. 1

• An ankle systolic pressure ≤50 mmHg or ABI <0.4 in a non-diabetic patient confirms CLI 1
• In diabetic patients (like this one), toe-brachial index (TBI) should also be obtained due to potential arterial calcification causing falsely elevated ABIs 1, 3
• A TBI <0.3 or toe pressure <30 mmHg indicates that amputation may be required without successful revascularization 1

Immediate Management Priorities

This patient requires urgent vascular specialist evaluation within 6-24 hours, as CLI represents a limb-threatening emergency. 1

Critical Actions:

• Cardiovascular risk assessment - Patients with CLI undergoing revascularization require cardiac risk stratification 1
• Anatomic imaging for revascularization planning - Duplex ultrasound, CTA, or invasive angiography to define anatomy 1, 4
• Revascularization evaluation - If anatomically possible, revascularization should be pursued to prevent limb loss 1, 5
• Wound inspection - Direct examination with shoes and socks removed to detect ulceration or tissue loss 1
• Infection screening - If any skin breakdown exists, systemic antibiotics should be initiated promptly 1

Common Pitfalls to Avoid

Do not delay revascularization evaluation with prolonged medical management alone - Without revascularization, the natural history of CLI leads to major limb amputation within 6 months 1, 6

Do not rely on ABI alone in this diabetic patient - Arterial calcification can cause falsely normal or elevated ABIs; always obtain TBI 1, 3

Do not assume absence of tissue loss means less urgency - Rest pain alone (Rutherford Category IV) is sufficient for CLI diagnosis and requires urgent intervention 1

Recognize this is NOT acute limb ischemia - The 2-week duration indicates chronic progression rather than acute thrombosis, but urgency remains high 1, 4

Prognosis Without Intervention

Patients with CLI face 1, 7:

• Major amputation risk within 6 months without revascularization
• 5-year mortality exceeding 50%
• Diabetes and renal failure further increase limb loss risk 1

This patient should be referred immediately to an interdisciplinary care team including vascular surgery, interventional specialists, and wound care experts for revascularization planning. 1