What is the diagnosis for an elderly patient presenting with unilateral ankle and leg swelling with pitting edema and wheezing in the lungs?

Diagnosis: Deep Vein Thrombosis (DVT) with Possible Pulmonary Embolism (PE)

This elderly patient presenting with unilateral leg swelling with pitting edema and wheezing most likely has deep vein thrombosis (DVT), and the wheezing raises concern for concurrent pulmonary embolism (PE). The combination of unilateral lower extremity edema and respiratory symptoms is a high-risk presentation requiring urgent evaluation.

Primary Diagnostic Consideration: DVT

Key Clinical Features Supporting DVT

• Unilateral pitting edema is the hallmark presentation of DVT 1
• Classic DVT symptoms include unilateral extremity edema (present in this patient), pain, heaviness, and unexplained persistent calf cramping 1
• Approximately one-third of DVT patients are completely asymptomatic, so the presence of clear symptoms increases diagnostic probability 2, 3
• Unilateral lower extremity edema below the knee commonly results from deep venous thrombosis, venous insufficiency, or lymphedema, with DVT being the most urgent diagnosis to exclude 4

Immediate Diagnostic Approach

The first-line diagnostic test must be venous duplex ultrasound (compression ultrasonography) of the proximal deep veins 1, 3:

• Position the patient with lower extremities dependent to facilitate vein distension 3
• Focus initially on common femoral and popliteal veins 3
• If proximal compression ultrasound is positive, initiate anticoagulation immediately without confirmatory venography 3
• If proximal ultrasound is negative but clinical suspicion remains high, obtain D-dimer testing and consider repeat ultrasound or imaging of iliac veins 1

Risk Stratification

Before imaging, assess clinical probability using validated tools 1:

• Wells score or revised Geneva score should be calculated
• Risk factors to evaluate: age ≥65 years (present in this elderly patient), previous DVT/PE, recent surgery or fracture, active malignancy, immobilization 1
• Advanced age alone doubles DVT/PE risk each decade after age 40 5

Secondary Concern: Pulmonary Embolism

Why Wheezing Raises PE Concern

The presence of wheezing in the context of unilateral leg swelling is a significant red flag for PE 2:

• Wheezing is specifically listed as a clinical finding in PE prediction models, though paradoxically it has a negative coefficient (meaning its presence slightly decreases PE probability in isolation) 2
• However, 70% of patients with proven PE have proximal DVT 2
• PE can occur in 50-60% of patients with untreated DVT, with mortality rates of 25-30% 2
• The majority of symptomatic DVT involves proximal clots, which lead to PE in 40-50% of cases, often without clinical manifestations 5

PE Diagnostic Considerations

If DVT is confirmed, evaluate for PE based on respiratory symptoms 2:

• Clinical patterns of PE include sudden collapse, pulmonary hemorrhage syndrome (pleuritic pain/hemoptysis), or isolated dyspnea 2
• Most PE patients are breathless and/or tachypneic (rate >20/min) 2
• Consider CT pulmonary angiography if respiratory symptoms are prominent or patient is hemodynamically unstable 2
• VQ scan is an alternative if CTA is contraindicated 2

Alternative Diagnoses to Consider

While DVT with possible PE is the primary concern, other causes of unilateral leg edema include 2, 1:

• Ruptured Baker's cyst - can mimic DVT but ultrasound will differentiate
• Cellulitis - would show erythema, warmth, fever (fever ≥38°C actually decreases PE probability) 2
• Chronic venous insufficiency - typically has dependent edema and hemosiderin deposition 6
• Lymphedema - presents with brawny, nonpitting edema 6

However, given the acute presentation with wheezing, DVT/PE must be excluded first before considering these alternatives 1, 3.

Critical Management Steps

1. Obtain venous duplex ultrasound immediately 1, 3
2. If DVT confirmed, initiate anticoagulation without delay 1, 3
3. Assess for PE clinically and with imaging if respiratory symptoms are significant 2
4. If anticoagulation is contraindicated, consider IVC filter 1

Common Pitfalls to Avoid

• Do not wait for D-dimer results before imaging in high-risk patients - proceed directly to ultrasound 1
• Do not assume wheezing is purely cardiac or pulmonary disease - it may represent PE 2
• Do not dismiss DVT because only one-third have classic symptoms - many are asymptomatic 2, 3
• Do not delay anticoagulation if proximal DVT is found on ultrasound - no confirmatory testing needed 3