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For further information, see CMDT Part 9-25: Pulmonary Venous Thromboembolism

Key Features

Essentials of Diagnosis

  • Predisposition to venous thrombosis, usually of the lower extremities

  • Usually dyspnea, chest pain, hemoptysis, or syncope

  • Tachypnea and a widened alveolar–arterial PO2 difference

  • Elevated rapid D-dimer and characteristic defects on CT pulmonary arteriography, ventilation-perfusion lung scan, or pulmonary angiogram

General Considerations

  • Third most common cause of death in hospitalized patients

  • Most cases are not recognized antemortem: < 10% with fatal emboli receive specific treatment

  • Pulmonary thromboembolism (PE) and deep venous thrombosis (DVT) are manifestations of the same disease, with the same risk factors

    • Immobility (bed rest, stroke, obesity)

    • Hyperviscosity (polycythemia)

    • Increased central venous pressures (low cardiac output, pregnancy)

    • Vessel damage (prior DVT, orthopedic surgery, trauma)

    • Hypercoagulable states, either acquired or inherited

  • Pulmonary thromboemboli most often originate in deep veins of the lower extremities

  • PE develops in 50–60% of patients with proximal lower extremity DVT; 50% of these events are asymptomatic

  • Hypoxemia results from vascular obstruction leading to dead space ventilation, right-to-left shunting, and decreased cardiac output

  • Other types of pulmonary emboli

    • Fat embolism

    • Air embolism

    • Amniotic fluid embolism

    • Septic embolism (eg, endocarditis)

    • Tumor embolism (eg, renal cell carcinoma)

    • Foreign body embolism (eg, talc in injection drug use)

    • Parasite egg embolism (schistosomiasis)

Clinical Findings

Symptoms and Signs

  • See Table 9–18

  • Clinical findings depend on the size of the embolus and the patient's preexisting cardiopulmonary status

  • Dyspnea occurs in 75–85% and chest pain in 65–75% of patients

  • Tachypnea is the only sign reliably found in more than 50% of patients

  • 97% of patients in the PIOPED study had at least one of the following

    • Dyspnea

    • Tachypnea

    • Chest pain with breathing

Table 9–18.Frequency of specific symptoms and signs in patients at risk for pulmonary thromboembolism.

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