Which of the following is the most common source of pulmonary embolism in clinical practice?
A. Thrombosis of the pulmonary artery itself
B. Right atrial thrombus
C. Paradoxical embolism from a patent foramen ovale
D. Deep vein thrombosis of the lower limbs
Explanation
Source of Pulmonary Embolism
Key Point
Deep vein thrombosis (DVT) of the lower extremities is the source of >90% of clinically significant pulmonary emboli. Thrombi form in the deep veins of the legs (popliteal, femoral, and iliac veins) and embolize to the pulmonary circulation.
High-YieldNEET PG
The classic triad for DVT formation (Virchow's triad) applies:
Venous stasis
Endothelial injury
Hypercoagulability
Clinical Pearl
Upper extremity DVT accounts for only 5–10% of PE cases and is often associated with central venous catheters or malignancy. Right atrial thrombi are rare and usually occur secondary to severe right ventricular dysfunction or arrhythmias, not as a primary source.
Mnemonic: DVT → PE — Deep Vein Thrombosis is the Direct Path to Pulmonary Embolism.
Why Lower Limb DVT Dominates
1.
Anatomical factors: Leg veins are prone to stasis due to gravity and dependency.
2.
Hemodynamic factors: Slow flow in deep leg veins favors thrombus formation.
3.
Risk factors: Immobility, surgery, malignancy, and hypercoagulable states preferentially affect the lower extremities.
Practice similar questions
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.
