Deep Vein Thrombosis

Key points

• • Deep vein thrombosis is a clot in a deep vein, most often in the calf or thigh, favoured by the factors of Virchow's triad.
• • Virchow's triad is slow blood flow (stasis), a raised tendency to clot, and injury to the vessel wall.
• • Risks include surgery, immobility, long travel, pregnancy, cancer and inherited clotting tendencies.
• • It causes a swollen, warm, tender and often red calf, though it can be silent.
• • Its danger is that part of the clot may break off and lodge in the lungs as a pulmonary embolism, which can be fatal.