Antiphospholipid syndrome

Question 1

what makes the definition of APS?

Answer 1

it is a combination of clinical manifestations and antibodies

need to have persistent antibodies

clinical criteria:

1. vascular thrombosis
   - arterial or venous
2. pregnancy morbidity
   - premature foetal death
   - recurrent spont abortion
   - preeclampsia! or eclampsia!

laboratory criteria (need 1, BUT the tests must be positive on 2 tests, taken at least 12 weeks apart)

1. IgG or IgM anticardiolipin
2. IgG or IgM anti-beta2-glycoprotein An
3. Lupus anticoagulant

Question 2

are there any manifestations of APS that are caused by antibody binding, RATHER than thrombosis?

Answer 2

the chorea seems to be associated with aPL binding to the basal ganglia

Question 3

is there any association between NMO and APS?

Answer 3

yes - there might be an antibody overlap between NMO and APS

Question 4

what is the histological hallmark of APS?

Answer 4

it is a “bland” thrombosis, which is to say, it is thrombosis without any evidence of inflammation

Question 5

what is the recommended management of APS?

what about aspirin?

immunosuppression?

Answer 5

this is tricky and possibly a bit contentious

Once the patient has had a thrombosis:
warfarin probably the best
target range for VENOUS thrombosis is 2-3

for ARTERIAL thrombosis: probably INR >3 (this is based on expert opinion though)

aspirin does not prevent thrombosis, but is reasonable to take this medication if CVD

there isn’t much evidence for immunosuppression (unless required for an associated autoimmune condition)

Question 6

how would you manage transitioning a patient from warfarin to IV heparin for a surgical procedure?

Answer 6

APTT is deranged at baseline because of inhibitors

therefore, use Factor Xa assay

this is useful for IV heparin AND for LMWH

Question 7

is there a particular way to manage recurrent miscarriages in APS?

note: this is secondary prevention

what about primary prevention?

Answer 7

this is a bit different than straight up APS management

at present, we have aspirin and LMWH (plus/minus IVIg, although theoretical inc risk of preeclampsia)

in the setting of definite APS pregnancy (but no miscarriages), the guidelines recommend aspirin (without LMWH)
- THIS IS FOR PRIMARY PROPHYLAXIS

Question 8

of the APS antibodies,

which are associated with false pos, which are more sens

what are the main tests?

Answer 8

anti-cardiolipin can be positive in syphilis (no clot associated) and things like Q fever

B2GP1 is a plasma protein that binds to the phospholipid. It is a bit more specific than aCL

the “lupus anticoagulatants” (note this is a plural) - this is a prolongation of the APTT. It encompasses things like anti-prothrombin. So, to get positive, you actually need to jump through extra results

Lupus anticoagulant is the highest risk for future events