What are the first steps for a patient experiencing burning sensations in the legs, blood pooling in the feet, and significant pressure or tightness in the right calf, limiting mobility to less than 5 minutes of standing or walking?

Urgent Evaluation for Deep Vein Thrombosis and Peripheral Arterial Disease

This patient requires immediate evaluation for deep vein thrombosis (DVT) with venous duplex ultrasound, as the acute worsening of unilateral calf tightness/pressure with severe functional limitation (unable to stand/walk >5 minutes) represents a potentially life-threatening condition that must be excluded first. 1, 2

Immediate Assessment Steps

Rule Out DVT First (Life-Threatening Priority)

• Obtain venous duplex ultrasound of the right leg immediately to exclude acute DVT, as unilateral calf symptoms with acute worsening require urgent evaluation regardless of bilateral presentation of other symptoms 1, 2
• The combination of unilateral right calf pressure/tightness that has "recently gotten a lot worse" with severe functional impairment is concerning for DVT, even though bilateral symptoms suggest chronic venous insufficiency 1

Critical Vascular Examination (Before Any Treatment)

Before considering any compression therapy or other interventions, you must rule out arterial insufficiency to avoid tissue necrosis and limb loss. 2, 3

• Palpate all four lower extremity pulses bilaterally (femoral, popliteal, dorsalis pedis, posterior tibial) and grade as: 0=absent, 1=diminished, 2=normal, 3=bounding 2, 3
• Auscultate for femoral or popliteal bruits indicating proximal stenosis 2
• Examine for dependent rubor, elevation pallor, asymmetric hair growth, nail bed changes, calf muscle atrophy, cool skin, or nonhealing wounds—all indicating arterial disease 2, 3
• Inspect between toes and plantar surfaces for ulceration, especially if diabetes or arterial disease risk factors present 2

Obtain Ankle-Brachial Index (ABI) Before Compression

• Measure ABI immediately as the primary diagnostic test to establish presence or absence of peripheral arterial disease 2, 3
• ABI 0.6-0.9 requires adjusted compression pressure; ABI <0.6 absolutely contraindicates compression therapy 1, 2
• If ABI >1.4 (suggesting calcified vessels), obtain toe-brachial index (TBI) or transcutaneous oxygen pressure (TcPO2) for accurate assessment 3

Differential Diagnosis Framework

Most Likely: Chronic Venous Insufficiency with Acute Exacerbation

The bilateral burning sensation, blood pooling in feet, symptoms worsening with prolonged standing/walking, and improvement with rest strongly suggest chronic venous insufficiency 4, 1

• Burning, heaviness, fatigue, and cramping that worsen by end of day or with prolonged standing/walking are classic for venous insufficiency 4, 1
• The patient's history of swelling after long air travel indicates baseline venous dysfunction 1

Consider Postthrombotic Syndrome (PTS)

• Ask specifically about any prior history of DVT, as PTS develops in 20-50% of patients within 1-2 years after DVT and presents identically to this patient's symptoms 1
• PTS can present as venous claudication with bursting leg pain during exercise from persistent venous obstruction of iliofemoral or popliteal veins 4

Rule Out Peripheral Arterial Disease (PAD)

The burning sensation and severe functional limitation raise concern for PAD, particularly if risk factors present 3, 5

• Evaluate for risk factors: age ≥65 years, diabetes, smoking history, hypertension, dyslipidemia, or known atherosclerotic disease elsewhere 2, 3
• Pain at rest, especially if worse at night and relieved by leg dependency, is pathognomonic for severe arterial insufficiency and critical limb ischemia 3
• Only one-third of PAD patients have typical claudication; atypical symptoms including rest pain are common 3, 5

Management Algorithm After Diagnostic Workup

If DVT Confirmed

• Initiate anticoagulation therapy immediately according to established guidelines 2
• Use compression stockings after acute phase to prevent postthrombotic syndrome 2

If Arterial Insufficiency Confirmed (ABI <0.9)

• Immediate vascular surgery consultation for nonhealing wounds, gangrene, or signs of critical limb ischemia 2, 3
• Initiate antiplatelet therapy (aspirin or clopidogrel) immediately 3
• Start high-intensity statin therapy 3
• Aggressive risk factor modification: smoking cessation, diabetes control, hypertension management 3

If Chronic Venous Insufficiency Confirmed (DVT and PAD Excluded)

• Prescribe graduated compression stockings with 20-30 mmHg pressure for mild-moderate disease or 30-40 mmHg for severe disease, but only after confirming ABI >0.6 1, 2
• Ensure proper fitting of compression garments to achieve optimal effectiveness 2
• Instruct on leg elevation above heart level when resting 1
• Recommend regular exercise to activate calf muscle pump function 1, 2
• Advise avoiding prolonged sitting or standing 1, 2

Critical Pitfalls to Avoid

• Never apply compression therapy without first ruling out arterial insufficiency—this can cause tissue necrosis and limb loss 2, 3
• Do not assume bilateral presentation excludes DVT; it can occur bilaterally and must be excluded 1
• Do not delay vascular assessment assuming pain is musculoskeletal, especially in patients with cardiovascular risk factors 3
• Do not rely solely on ABI in patients with diabetes or chronic kidney disease; falsely elevated values from medial arterial calcification can mask severe disease 3
• Failing to examine for wounds in diabetic or arterial disease patients can lead to missed diagnoses 2