A 68-year-old man develops sudden onset pleuritic chest pain and dyspnea 10 days after total knee replacement. CT pulmonary angiography confirms pulmonary embolism. What is the most common source of the embolus?

• A Upper extremity deep veins
• B Right-sided cardiac chambers
• C Pelvic veins
• D Deep veins of the lower extremities ✓

Explanation

Over 95% of pulmonary emboli originate from deep vein thrombosis of the lower extremities, particularly the popliteal, femoral, and iliac veins. Postoperative immobilization predisposes to lower extremity DVT. Pelvic veins and upper extremity veins are less common sources. Right heart thrombi cause PE only in specific settings like atrial fibrillation or right ventricular dysfunction.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.