AIM • Student Memory Support
Venous Thromboembolism: Deep Vein Thrombosis & Pulmonary Embolism
Final Year MBBS • CVS Module • High-yield revision and memory reinforcement
1. High-Yield Flashcards
Tap each question to reveal the answer.
What three abnormalities form Virchow’s triad?
Venous stasis, endothelial injury and hypercoagulability.
What common presentation should make you suspect lower-limb DVT?
New unilateral painful leg swelling with edema, warmth or tenderness.
What is the main role of D-dimer in suspected VTE?
To help exclude VTE in an appropriately low-probability patient.
Why does an elevated D-dimer not confirm DVT?
It is nonspecific and may rise in malignancy, inflammation, pregnancy or after surgery.
What ultrasound finding supports DVT?
Failure of the deep vein to compress.
How does DVT cause pulmonary embolism?
Part of the thrombus detaches and travels through the right heart to the pulmonary arteries.
What symptoms commonly suggest pulmonary embolism?
Sudden dyspnea, pleuritic chest pain, tachypnea and tachycardia.
Why can PE cause hypoxemia?
Pulmonary arterial obstruction produces ventilation-perfusion mismatch.
Why can a large PE cause shock?
Acute rise in pulmonary vascular resistance causes RV failure, reduced LV filling and low cardiac output.
What is the main confirmatory imaging test for PE in most stable patients?
CT pulmonary angiography.
What CTPA finding supports pulmonary embolism?
An intraluminal pulmonary arterial filling defect.
What is the central treatment for DVT and most pulmonary emboli?
Anticoagulation.
What does anticoagulation achieve in acute VTE?
It prevents clot extension and further embolization while endogenous fibrinolysis acts.
When should reperfusion therapy be considered in PE?
When PE causes major hemodynamic compromise such as persistent hypotension or shock.
2. Mnemonics
Mnemonic Title: Virchow’s Triad
S-E-H
Meaning: Stasis • Endothelial injury • Hypercoagulability
Mnemonic Title: Main PE Presentation
D-P-T
Meaning: Dyspnea • Pleuritic chest pain • Tachycardia / tachypnea
Mnemonic Title: VTE Diagnostic Logic
P-T-I
Meaning: Probability → Test selection → Interpretation
3. Memory Tables
DVT vs Pulmonary Embolism
| Feature | DVT | Pulmonary Embolism |
|---|---|---|
| Main site | Deep veins | Pulmonary arteries |
| Typical presentation | Unilateral painful swollen leg | Sudden dyspnea ± pleuritic chest pain |
| Key test | Compression ultrasonography | CT pulmonary angiography |
| Characteristic finding | Non-compressible deep vein | Pulmonary arterial filling defect |
| Main treatment | Anticoagulation | Anticoagulation; reperfusion if unstable |
| Major danger | Embolization | RV failure and shock |
4. Rapid Revision Points — Last-Minute Revision
- DVT and PE are two manifestations of the same venous thromboembolic process.
- Virchow’s triad explains thrombus formation: stasis, endothelial injury and hypercoagulability.
- Sudden unilateral painful leg swelling should trigger assessment for DVT.
- D-dimer is most useful for exclusion in an appropriately low-probability patient.
- An elevated D-dimer alone does not confirm VTE.
- Loss of venous compressibility on ultrasound supports DVT.
- PE causes hypoxemia mainly through ventilation-perfusion mismatch.
- CTPA demonstrates pulmonary arterial filling defects in PE.
- Anticoagulation prevents thrombus extension and recurrent embolization.
- Hypotension or shock in PE indicates severe hemodynamic compromise and possible need for reperfusion.
KMU Trap: A normal chest radiograph or nonspecific ECG does not exclude pulmonary embolism.
5. Clinical Memory Hooks
Clinical Hook: Postoperative immobility + unilateral calf swelling → think DVT.
Clinical Hook: DVT + sudden dyspnea and pleuritic pain → suspect pulmonary embolism.
Clinical Hook: PE + hypotension or syncope → acute RV strain with threatened circulation.
Clinical Hook: Low clinical probability + negative D-dimer → acute VTE becomes very unlikely.
6. Starred High-Yield Exam Points
- ⭐ DVT + PE = one VTE spectrum; the deep venous thrombus is commonly the embolic source.
- ⭐ Non-compressible deep vein on ultrasound is the key imaging clue for DVT.
- ⭐ D-dimer is a rule-out aid in low-probability patients; a positive result is nonspecific.
- ⭐ CTPA showing a pulmonary arterial filling defect supports PE.
- ⭐ Anticoagulation is the central treatment for DVT and most stable PE.
- ⭐ PE with persistent hypotension or shock requires urgent stabilization and consideration of reperfusion therapy.