A. Hereditary thrombophilias

 

GP's role

 

  1. Identify individuals with a personal or family history of thromboembolism.
  2. Include:
  3. Age of onset
  4. Site and extent of thrombosis
  5. Precipitating/contributing factors
  6. Perform a risk assessment – should patient be screened for thrombophilia?
  7. Arrange screening if indicated.
  8. Factor V Leiden and prothrombin variant genetic testing is available on the MBS only if the patient has:
  9. A personal history of deep vein thrombosis (DVT), or
  10. A family history of a diagnosed inherited thrombophilic condition
  11. Refer family to relevant support group (see Contacts, Support and Testing).
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Features

  1. Normal haemostasis results from a balanced interaction between platelets and plasma clotting proteins
    (see Figure 1).
  2. Predisposition to thrombosis or ‘thrombophilia’ may be due to an excess of procoagulant factors, a deficiency of anticoagulant factors, or abnormal fibrinolysis. ‘Toxic’ effects on the endothelium may also
    predispose to thrombus formation.
  3. There are a number of different types of hereditary thrombophilia conditions which are distinguished by their different causes (see Table 1).
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Figure 1

The action of coagulant factors in the blood

Figure 1

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Table 1

The major hereditary thrombophilia conditions

Table 1

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  1. The risk of thrombosis is higher for patients with group 1 conditions than group 2 conditions.
  2. Group 2 conditions occur approximately 5 times more frequently than group 1 conditions.