Antiphospholipid syndrome

Question 1

What is antiphospholipid syndrome?

Answer 1

Characterised by presence of antiphospholipid antibodies (APL) in the plasma, venous and arterial thromboses, recurrent foetal loss and thrombocytopenia.

Question 2

What is the aetiology of antiphospholipid syndrome?

Answer 2

Once APL is present, a second hit is needed for development of the syndrome such as infectious agents.

Question 3

What are the risk factors in antiphospholipid syndrome?

Answer 3

Susceptible individuals include those with rheumatic diseases such as SLE

Question 4

What is the pathophysiology of antiphospholipid syndrome? (x1 point + 2 symptoms)

Answer 4

• APL recognise a variety of phospholipid-binding plasma proteins such as beta2-glycoprotein-I, prothrombin, and phospholipids expressed on platelets and monocytes.
• Beta2-glycoprotein-I is a complement control protein and clotting/platelet aggregation inhibitor. It is the major antigen target of APL and linked with thrombosis.
• Complement activation is critical for pregnancy-related complications

Question 5

What are the types of antiphospholipid syndrome?

Answer 5

Primary (patients with systemic autoimmune disease) or secondary (patients with other autoimmune disease)

Question 6

What is the epidemiology of antiphospholipid syndrome: Age? Gender? Ethnicity?

Answer 6

More common in young females. Most patients are white.

Question 7

What are the signs and symptoms of antiphospholipid syndrome? (x7 (x3))

Answer 7

• VASCULAR: history of arterial thromboses (stroke), venous thromboses (DVT, PE), neurological presentations such as headaches, chorea and epilepsy (from stroke or TIA)
• PREGNANCY-RELATED: recurrent miscarriages
• FEATURES OF THROMBOCYTOPENIA
• SYMPTOMS/SIGNS OF SLE: such as arthralgia since underlying SLE is common
• SIGNS OF VALVULAR HEART DISEASE: from fibrin deposition in valves
• LIVEDO RETICULARIS: mottled purplish discoloration of the skin from fibrin deposition in skin arterioles – see photo
• May get signs of APL nephropathy such as oedema

Question 8

What are the blood investigations for antiphospholipid syndrome? (x3)

Answer 8

• FBC: low platelets
• U&Es: may show nephropathy
• Clotting screen: raised APTT

Question 9

What other investigations are there for antiphospholipid syndrome? (x3)

Answer 9

• !!! LUPUS ANTICOAGULATION ASSAYS: clotting assays showing effects of APL on phospholipid dependent factors in the coagulation cascade
• ELISA: for anticardiolipin and anti-B2-GPI antibodies (common antiphospholipid antibodies)
• DOPPLER SCAN: to assess thrombosis