Internal Medicine · Year 3 · from Internal Medicine
Case 1: Deep Vein Thrombosis
Patient Presentation
A 45-year-old woman presents with 3 days of progressive left leg swelling and pain. She returned from a 12-hour flight from Europe 5 days ago. She has a history of obesity and recently started oral contraceptive pills for menorrhagia. She denies shortness of breath, chest pain, or hemoptysis.
Vital Signs
- Blood Pressure: 132/78 mmHg
- Heart Rate: 82 bpm
- Respiratory Rate: 16/min
- Oxygen Saturation: 98% on room air
- Temperature: 37.2°C
Physical Examination
- General: Well-appearing, mild discomfort
- Cardiovascular: Regular rhythm, no murmurs
- Pulmonary: Clear
- Left lower extremity: Swelling from ankle to mid-thigh, 4 cm circumference difference at calf, warmth, erythema, tenderness along medial thigh
- Right lower extremity: Normal
Initial Workup
- D-dimer: 2,450 ng/mL (normal <500)
- CBC: Normal
- Creatinine: 0.8 mg/dL
- Compression ultrasound: Non-compressible left common femoral and popliteal veins
Clinical Image
Figure 1: Compression ultrasound demonstrating non-compressibility of the femoral vein (arrow), diagnostic of deep vein thrombosis. Normal veins completely compress with probe pressure.
Image Source: Educational illustration for teaching purposes.
Questions
- What is this patient's Wells score for DVT and pretest probability?
- A) Low probability
- B) Moderate probability (Wells 1-2)
- C) High probability (Wells ≥3)
- D) Cannot calculate
- What is the role of D-dimer in DVT diagnosis?
- A) Confirms DVT when positive
- B) Rules out DVT when negative in low/moderate pretest probability patients
- C) Should be obtained in all patients
- D) Not useful in DVT evaluation
- What is the appropriate initial anticoagulation for this patient?
- A) Warfarin alone
- B) DOAC (rivaroxaban, apixaban) or LMWH followed by warfarin
- C) Aspirin only
- D) IVC filter placement
- What is the recommended duration of anticoagulation for this patient?
- What are this patient's risk factors for VTE?
Answers
- C) High probability (Wells ≥3) - Wells criteria for DVT:
- Active cancer: 0
- Paralysis/immobilization: 0
- Bedridden >3 days or surgery <12 weeks: 0
- Tenderness along deep veins: 1
- Entire leg swollen: 1
- Calf swelling >3 cm: 1
- Pitting edema: 1
- Collateral superficial veins: 0
- Alternative diagnosis as likely: 0
- Total: 4 (≥3 = high probability)
- B) Rules out DVT when negative in low/moderate pretest probability patients - D-dimer has high negative predictive value. A negative D-dimer in low/moderate probability patients effectively excludes DVT. High pretest probability patients should proceed directly to imaging.
- B) DOAC (rivaroxaban, apixaban) or LMWH followed by warfarin - Options include:
- DOACs (rivaroxaban, apixaban) as monotherapy - preferred for most patients
- LMWH bridge to warfarin (target INR 2-3)
- LMWH alone (preferred in cancer-associated thrombosis)
- DOACs are contraindicated with estrogen-containing contraceptives should be discontinued
- Recommended duration of anticoagulation:
- This is a provoked DVT (long-haul flight + OCPs)
- Standard treatment: 3 months
- After 3 months, reassess: if provoking factors removed (stopped OCPs, no further immobilization), can discontinue
- If unprovoked or ongoing risk factors, consider extended anticoagulation
- Proximal DVT has higher recurrence risk than distal DVT
- Risk factors for VTE in this patient:
- Prolonged immobilization (12-hour flight)
- Oral contraceptive pills (estrogen increases clotting factors)
- Obesity (inflammatory state, venous stasis)
- These are transient/reversible risk factors
- Counsel on VTE prevention for future travel (hydration, mobilization, compression stockings, consider prophylactic LMWH for high-risk patients)