Anti-phospholipid syndrome (APS)


Recurrent arterial +/or VTE with no signs connective tissue disease

Anti-phospholipid antibodies APL (IgM and IgG)

  • Present in 2% of people (50% on those with SLE = "secondary APS")
  • Generation may have trigger e.g. phenytoin, chlorpromazine, quinidine and some antibiotics
  • Miscellaneous triggers include: malignancy, HIV, viral infections (these usually not at VTE risk)

Clinical presentation

  • VTE/PE (± ↑ Pulmonary BP)
  • CVA or venous thromboses
  • Thrombocytopenia or haemolytic anaemia
  • Skin ischaemia (cyanosis/gangrene, livedo reticularis, discoid rash and chronic ulcers)
  • Cardiac (valvular Libman-Sacks as in SLE) lesions
  • Ocular thrombosis
  • Obstetric: miscarriage, IUGR, eclampsia
  • Rarely - "catastrophic APS", "Asherson syndrome" - fulminant multi organ failure


  • DIC
  • Endocarditis
  • Thrombotic or heparin-induced thrombocytopenia
  • Hyper-coagulable states


  • Anticoagulation (INR 2-3)
  • Consider Hydroxychloroquine
  • Aspirin (evidence for/against is weak)
  • Clopidogrel (no strong evidence)

Content by Dr Íomhar O' Sullivan. Last review Dr ÍOS 12/04/23.