Deep Venous Thrombosis (DVT)

Deep Venous Thrombosis

Pathophysiology & Management

FreeMedSite USMLE STEP 1 REVIEW

Interactive Study:

Presentation

Clot formation in deep veins (usually lower extremity) presenting with:
Swelling • Redness • Warmth • Pain

Virchow's Triad

Mnemonic: S.H.E.

• S Stasis: Post-op immobility, long flights/drives.
• H Hypercoagulability: Factor V Leiden, OCPs, Pregnancy, Malignancy.
• E Endothelial Damage: Trauma, surgery, catheters.

Diagnosis

Screening

D-dimer: High sensitivity / Low specificity. Excellent for ruling out DVT.

Definitive

Compression US with Doppler: Imaging of choice to confirm diagnosis.

Management

Acute (Inpatient)

• UFH (IV/SC)
• LMWH (Enoxaparin)

Long-term (Outpatient)

• DOACs (Rivaroxaban, Apixaban)

Clinical Pearl

"Most pulmonary emboli (PE) arise from the proximal deep veins: iliac, femoral, and popliteal."

1. Name the three components of Virchow's Triad (Mnemonic: SHE).

Answer: Stasis, Hypercoagulability, Endothelial damage.

2. Which veins are the most common source of Pulmonary Emboli?

Answer: Proximal veins (Iliac, Femoral, Popliteal).

3. Why is D-dimer useful despite its low specificity?

Answer: High sensitivity allows it to rule out DVT (SnOut) if negative.

4. What is the definitive imaging test of choice for DVT?

Answer: Compression Ultrasound with Doppler.

5. What is the most common inherited cause of hypercoagulability?

Answer: Factor V Leiden.