What are the causes and risk factors for pulmonary embolism?
Pulmonary embolus is the end result of a deep vein thrombosis or blood clot elsewhere in the body. Most commonly, the DVT begins in the leg, but they also can occur in veins within the abdominal cavity or in the arms.
The risk factors for a pulmonary embolism are the same as the risk factors for deep vein thrombosis. These are referred to as Virchow's triad and include:
- prolonged immobilization or alterations in normal blood flow (stasis)
- increased clotting potential of the blood (hypercoagulability)
- damage to the walls of the veins.
Examples of these include the following:
- Extended travel (sitting in a car, airplane, train, etc.)
- Hospitalization or prolonged bed rest
Increased blood clotting potential
- Medications: birth control pills, estrogen
- Genetic predisposition: most commonly, Factor V Leiden deficiency, MHFTHR mutation, Protein C or Protein S deficiencies or anitithrobin III deficiency
- Polycythemia (increased number of red blood cells, the opposite of anemia)
- Pregnancy, including the postpartum period up to 6 to 8 weeks after delivery
Damage to vessel wall
- Prior deep venous thrombosis
- Trauma to the lower leg with or without surgery or casting