Case 239 - Discussion

Uploaded: 2008-05-30, Updated: 2008-05-30

Acute Pulmonary Thromboembolism

GENERAL FEATURES

  • Over 600,000 PE each year in US.

  • 200,000 deaths annually with PE in US.

  • 1/100 DVT patients die due to PE.

  • Most PE caused by DVT.

  • With prompt management, the mortality of PE reduced from 30% to <10%.

  • “Economy Class Syndrome" due to prolonged sitting on long flights.

  • Risk Factors:

    • Immobility, bed rest or sitting for a long time

    • Obesity

    • Age: >40

    • Previous history of DVT or PE

    • Metastatic malignancy

    • Vein disease (such as varicose veins)

    • Smoking

    • Hormone therapy or oral contraceptives

    • Pregnancy or post-partum

    • Recent surgery

    • Limb trauma and/or orthopedic procedures

    • Genetic factors and coagulation abnormalities

GROSS FINDINGS (PE vs Post-Mortem Clots )

  • Pulmonary Thromboemboli

    • Irregular or outlines of the vein in which it formed;

    • Firm, fragile, alternating pale and dark layers;

    • Adhesion to the vascular wall (if organized);

    • Infarct of lung, wedge-shaped.

  • Post-Mortem Clots

    • Soft, irregular, gelatinous;

    • Two major layers:

      • Dependent layer: red and dark red RBC (“currant jelly");

      • Supernatant layer: white/yellow plasma and WBC ("chicken fat").

MICROSCOPIC FINDINGS of PE

  • Irregular or rounded outline;

  • Alternating pale and red layers (“lines of Zahn“):

    • Red: RBC

    • Pale: fibrin and WBCs

  • Organization and adhesion to the vascular wall.

Autopsy and Pathological Diagnosis of PE

  • History and clinical lab tests

  • Physical examination and measurement of the legs looking for evidence of DVT

  • Lift-Leg Test

  • Dissection of the legs: directly searching for PE.

  • In situ dissection of the pulmonary artery and its main branches

  • Further sections of the lungs, looking for fresh or old PE or infarcts

  • Microscopic evaluation

TREATMENT AND PROGNOSIS

  • Anticoagulation: Heparin, Warfarin;

  • Thrombolytics: only indicated when hemodynamic instability;

  • IVC filters: indicated if there are contraindications to anticoagulation;

  • Surgical Removal.