In a 69‑year‑old woman with hypertension, hyperlipidemia, pre‑diabetes, vitamin D deficiency, dementia and major depressive disorder who presents with unilateral non‑pitting left lower‑extremity swelling without erythema, warmth or skin tightness, what is the most appropriate next step in evaluation and management?

Unilateral Lower Extremity Swelling in Elderly Patient

Immediate Next Step: Duplex Ultrasound

The most appropriate next step is bilateral lower extremity duplex Doppler ultrasound to evaluate both venous thrombosis and arterial insufficiency, as unilateral non-pitting swelling in this patient requires urgent differentiation between these two conditions despite the absence of classic symptoms. 1

Clinical Reasoning

Why Duplex Ultrasound is Essential

• Unilateral swelling strongly suggests localized vascular pathology (deep venous thrombosis or venous obstruction) rather than systemic causes, making this the primary diagnostic concern 1
• The "non-pitting" characteristic does not exclude DVT—this can occur with chronic venous obstruction or when swelling is severe 1
• Even "asymptomatic" presentations carry significant morbidity risk: untreated DVT leads to pulmonary embolism in 50-60% of cases with 25-30% mortality 1
• The absence of warmth, erythema, or skin tightness does not rule out vascular pathology and should not delay imaging 1

Assessment of Arterial vs. Venous Pathology

Document the following immediately:

• Arterial assessment: Palpate all pulses bilaterally (femoral, popliteal, dorsalis pedis, posterior tibial) and grade them numerically (0=absent, 1=diminished, 2=normal, 3=bounding) 2
• Capillary refill time and skin temperature gradient between limbs 1
• Motor and sensory function in both lower extremities 2
• The "5 Ps plus temperature": Pain, paralysis, paresthesias, pulselessness, pallor, and polar (cold) extremity—any of these indicate limb jeopardy requiring immediate vascular surgery consultation 1

Risk Stratification Based on Patient Profile

High Cardiovascular Risk Factors Present

This patient has multiple atherosclerotic risk factors that increase both arterial and venous disease likelihood:

• Hypertension increases peripheral arterial disease risk 2.5- to 4-fold 2
• Hyperlipidemia is strongly associated with lower extremity PAD 2
• Pre-diabetes increases PAD risk 2- to 4-fold and is present in 12-20% of persons with lower extremity PAD 2
• Age 69 years places her in the high-prevalence category for both arterial and venous disease 2

Dementia as a Complicating Factor

• Patients with dementia may have impaired ability to report symptoms accurately, making objective vascular assessment even more critical 2
• The absence of pain complaints does not indicate absence of serious pathology—similar to diabetic neuropathy masking critical limb ischemia 2

Management Algorithm After Duplex Ultrasound

If DVT is Confirmed:

• Initiate anticoagulation immediately to prevent thrombus propagation and reduce pulmonary embolism risk 1
• Standard anticoagulation protocols apply regardless of "asymptomatic" presentation 1

If Arterial Insufficiency is Confirmed:

• Measure ankle-brachial index (ABI): Values ≤0.90 confirm peripheral arterial disease 1, 3
• Initiate cardiovascular risk reduction immediately, even if "asymptomatic": 1, 3
  • Antiplatelet therapy (clopidogrel 75 mg daily preferred, or aspirin 75-100 mg daily) 3
  • High-dose statin therapy targeting LDL-C <100 mg/dL 3
  • Blood pressure control to <140/90 mmHg 3
  • Optimize glucose control to hemoglobin A1C <7% 3
• "Asymptomatic" lower extremity PAD carries 2-5 times higher risk of MI, stroke, and death compared to those without PAD 2, 1

If Both Studies are Normal:

• Consider alternative diagnoses: lymphedema, lipedema, chronic venous insufficiency without acute thrombosis, or systemic causes (though less likely given unilateral presentation) 4

Critical Pitfalls to Avoid

• Do not delay imaging based on "non-pitting" edema or absence of warmth/erythema—these features do not exclude life-threatening conditions 1
• Do not assume bilateral assessment is unnecessary—comparing both limbs provides critical diagnostic information 1
• Do not dismiss vascular pathology in patients with dementia who may underreport symptoms 2
• Do not wait for symptoms to worsen—time is tissue in both arterial and venous emergencies 1

Urgent Vascular Surgery Consultation Indications

Consult immediately if any of the following are present:

• Absent or severely diminished pulses 1
• Motor weakness or paralysis 1
• Sensory deficits beyond mild paresthesias 1
• Mottled or cyanotic skin 1
• Muscle rigidity suggesting compartment syndrome 1
• Delays beyond 4-6 hours risk permanent damage and limb loss 1