Antiphospholipid syndrome

Question 1

What is it?

Answer 1

association of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibody, and/or anti-beta2-glycoprotein I) with a variety of clinical features characterised by thromboses (arterial and venous) and pregnancy-related morbidity.

Question 2

Epidemiology

Answer 2

• Associated with SLE in 20-30% of cases
• Often occurs as a primary disease (no underlying autoimmune disease)
• More common in females than males
• APS has been reported to have a prevalence of between 1.0% and 5.6% in normal healthy populations and may increase with age.

Question 3

Pathophysiology

Answer 3

• antiphospholipid antibodies (aPL) play a role in thrombosis by binding to phospholipid on the surface of cells such as endothelial cells, platelets and monocytes
• Once bound, it alters the functioning of those cells leading to thrombosis and/or miscarriage.
• Thrombotic tendency affects cerebral, renal and other vessels

Question 4

Antiphospholipid antibodies (aPL) cause CLOTs, what are clots

Answer 4

• Coagulation defect
• Livedo reticularis - lace-like purplish discolouration of skin
• Obstetric issues i.e. miscarriage
• Thrombocytopenia (low platelets)

Question 5

Clinical manifestations

Answer 5

• hrombosis
• Miscarriage
• Livedo-reticularis
• Thrombocytopenia
• Ischaemic stroke, TIA, MI - arteries
• Deep vein thrombosis, Budd-chiari syndrome - veins
• Valvular heart disease, migraines, epilepsy

Question 6

Investigations

Answer 6

• Anticardiolipin test:
  
  • Detects IgG or IgM antibodies that bind the negatively charged phospholipid - cardiolipin
• Lupus anticoagulant test:
  
  • Detects changes in the ability of the blood to clot
• Anti-B2-glycoprotein I test:
  
  • Detects antibodies that bind B2-glycoprotein I, a molecule that interacts closely with phospholipids
• A persistently positive test (positive on at least two occasions more than 12 weeks apart) in one or more of these tests, along with clinical features is needed to diagnose APS

Question 7

Management

Answer 7

• Long term warfarin to minimise thrombosis
• Pregnant women:
  
  • Oral aspirin and SC heparin early on in pregnancy
  • Reduces chance of miscarriage but pre-eclampsia and poor fetal growth remain common
• Prophylaxis:
  
  • Aspirin or Clopidogrel for people with aPL, especially those with a high IgG aPL (antiphospholipid antibody)