Deep vs. Superficial Vein Thrombosis: Phlebothrombosis, Thrombophlebitis & PE Risk

Phlebothrombosis = DVT (deep vein thrombosis). Clot in deep venous system (femoral, popliteal, iliac).

Thrombophlebitis = Superficial vein thrombosis (SVT) + inflammation. Clot in saphenous/accessory veins.

PE Risk Difference

• DVT: High PE risk. Large caliber, high flow → embolus dislodges → travels to pulmonary artery. Proximal DVT (above knee) > distal.
• SVT: Low PE risk (<1–2%). Small veins, low flow, adherence to wall. Exception: SVT extending to saphenofemoral junction (SFJ) → treat as DVT.

Shared Risk Factors (Virchow's Triad)

• Stasis (immobility, travel, HF), Hypercoagulability (cancer, Factor V Leiden, OCP, pregnancy), Endothelial injury (surgery, trauma, IV catheter).
• Age >60, obesity, smoking amplify.

Action

Sudden dyspnea, pleuritic chest pain, hemoptysis, syncope → CT pulmonary angiogram / V/Q scan immediately. Anticoagulate DVT/SVT near SFJ.