Thrombophilias

Overview

Also known as a hypercoagulable state, thrombophilias are characterised by a predisposition to thromboembolism. They can be inherited or acquired.

Causes

Heritable causes

• Factor V Leiden (activated protein C resistance) – the most common inherited thrombophilia:
  • Activated protein C acts as a natural anticoagulant, in activated protein C resistance, it does not function, leading to hypercoagulable states
  • Autosomal dominant inheritance
• Antithrombin III deficiency:
  • Antithrombin III usually acts as a natural anticoagulant 
• Protein C deficiency:
  • Protein C usually acts as a natural anticoagulant
• Protein S deficiency:
  • Protein S usually acts as a natural anticoagulant

Acquired causes

• Antiphospholipid syndrome
• Malignancy
• Myeloproliferative disorders
• Disseminated intravascular coagulation (DIC)
• Nephrotic syndrome
• Inflammatory bowel disease
• Pregnancy and post-partum
• Behçet’s disease
• Antiphospholipid syndrome
• Heparin-induced thrombocytopenia (HIT)
• Chemotherapy
• Surgery
• Oestrogen-containing oral contraceptives and hormone replacement therapy
• Smoking
• Obesity
• HIV infection
• Long-haul flights