Introduction
This topic covers venous thrombosis and inflammation of veins: superficial thrombophlebitis and deep vein thrombosis (called phlebothrombosis in older Eastern European terminology). A good answer defines both, explains the causes and mechanism, describes the clinical picture, diagnosis and differential diagnosis, treatment, and the main complications, above all pulmonary embolism.
Definition and classification
Thrombophlebitis is thrombus formation in a vein with an accompanying inflammatory reaction of the venous wall. Phlebothrombosis is thrombus formation in a vein with little or no inflammation, most often in a deep vein of the leg. Today the clinically important distinction is between superficial and deep veins, because they differ in risk and treatment.
Causes and mechanism
Thrombosis follows Virchow's triad: venous stasis, endothelial injury and hypercoagulability. Often more than one factor acts together.
- Stasis: prolonged immobilisation, bed rest, long travel, heart failure, obesity, paralysis of the limb.
- Endothelial injury: surgery, trauma, fractures, central venous catheters, varicose veins.
- Hypercoagulability: inherited thrombophilia (factor V Leiden, prothrombin G20210A mutation, deficiencies of antithrombin, protein C or protein S), antiphospholipid syndrome, malignancy, pregnancy and puerperium, oral contraceptives and hormone therapy, nephrotic syndrome.
In superficial thrombophlebitis, the cause is usually local: intravenous cannulation, injection of irritant drugs, or varicose veins. Deep thrombosis in the leg usually starts in the calf veins or at the valve pockets and can extend proximally, where it is more dangerous.