60. Thrombosis. Causes and consequences

Page created on December 12, 2018. Last updated on May 25, 2019 at 12:09

Thrombosis is a common condition. Virchow’s triad described the major risk factors for thrombosis:

  • Impaired blood flow (stasis)
    • Immobilization (bed-ridden people, long flights)
    • Varicose veins
    • Obesity
    • Pregnancy
    • Polycythaemia vera (viscosity increased)
    • Stroke
  • Endothelial damage
    • Hypertension
    • Phlebitis
    • Vasculitis
    • Ischemic injury
  • Hypercoagulability
    • Leiden mutation of factor V
    • Smoking
    • Antithrombin-III deficiency
    • Protein C or S deficiency
    • Polycythaemia vera (viscosity increased)
    • SLE
    • Oestrogen therapy
    • Obesity
    • Cancer

The major consequence of venous thrombosis is pulmonary embolism. The thrombus usually occurs from the deep veins of the leg (deep vein thrombosis, DVT). Common symptoms of partial pulmonary embolisms include:

  • Dyspnoea
  • Chest pain
  • Haemoptysis
  • Cough
  • Tachypnoea
  • Tachycardia

Many pulmonary embolisms are asymptomatic, making them impossible to diagnose. Multiple microembolisms will progressively decrease the total diameter of pulmonary vessels, which causes type 4 pulmonary hypertension and cor pulmonale. Total and sub-total pulmonary embolisms are deadly.

Diagnosis: Laboratory findings show increased amount of D-dimers, a breakdown product of fibrin. Echocardiography, CT, pulmonary angiography and doppler ultrasound can also be used.

Venous thrombosis also has local consequences:

  • Swelling
  • Cyanosis
  • Ischaemia

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