Antiphospholipid Syndrome

Question 1

What is APS?

Answer 1

An acquired disorder characterised by a predisposition to:

1) both venous and arterial thromboses

2) recurrent fetal loss

3) thrombocytopenia

Question 2

APS may occur as a primary disorder or 2ary to other conditions.

What condition does it most commonly occur 2ary to?

Answer 2

SLE

Around 30% of patients with SLE have positive APS antibodies.

Question 3

APTT in antiphospholipid syndrome?

Answer 3

Antiphospholipid syndrome causes a paradoxical RISE in APTT

Question 4

Why does APS cause a rise in APTT?

Answer 4

Due to an ex-vivo reaction of the lupus anticoagulant autoantibodies with phospholipids involved in the coagulation cascade.

Question 5

What antibodies are most commonly seen in APS?

Answer 5

anticardiolipin antibodies

Question 6

Platelets in APS?

Answer 6

Thrombocytopenia

Question 7

APTT in APS?

Answer 7

Reduced

Question 8

Mx of APS?

Answer 8

1) 1ary thromboprophylaxis –> low-dose aspirin

2) 2ary thromboprophylaxis:
- initial venous thromboembolic events: lifelong warfarin with a target INR of 2-3
- recurrent venous thromboembolic events: lifelong warfarin; if occurred whilst taking warfarin then consider adding low-dose aspirin, increase target INR to 3-4
- arterial thrombosis should be treated with lifelong warfarin with target INR 2-3