Curriculum · Respiratory
Pulmonary embolism
What it is
DVT and PE are the two ends of venous thromboembolism, and the causes sit in Virchow's triad: stasis, vessel wall injury, and hypercoagulability. Acute massive pulmonary embolism is the most common cause of acute cor pulmonale, where a sudden increase in right ventricular afterload leads to right ventricular dilation and dysfunction.
Causes and risk
Risk factors: age, type of surgery (major surgery over 45min), lower limb surgery, BMI, ambulation over 72hr, tourniquet time over 45min, Hx of DVT or PE, immobilization, pregnancy, and a PMH of malignancy or coagulopathy. The procedures that carry it are spine fractures, joint replacement surgery of knee or hip, hip fractures, and polytrauma. In a young patient also ask about pregnancy, hormonal therapy such as contraceptives and fertility treatment, and a family history of thrombophilia. Thrombophilia is a deficiency in one of the natural anticoagulants that leads to thrombosis: these factors normally stop the coagulation process, and without them thrombus forms. Such patients present with unprovoked venous thromboembolism, with no apparent cause. Other diseases carry it too. Antiphospholipid syndrome causes arterial or venous thrombosis and pulmonary embolism. Polycythemia vera has thrombotic complications: DVT, PE, Budd-Chiari, portal vein thrombosis, thrombophlebitis. And a young woman with massive pulmonary embolism, focal convulsions, mouth ulcers and pseudofolliculitis has Behcet's disease. A confirmed deep vein thrombosis or pulmonary embolism is also one of the points asked for where a woman presents with hot flushes and night sweats, beside risk factors for osteoporosis and for cardiovascular disease.