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2. INTRODUCTION
๏ Constellation of clinical conditions, associated with a
persistently positive test for an antiphospholipid
antibody
Features:-
- Recurrent venous and arterial thromboembolism
- Adverse pregnancy outcomes (abortion >3
times)
- Abnormal fetus after 10 weeks
- Pre-eclampsia, eclampsia
- Thrombocytopenia
- Neurologic: Chorea, Migraine, Epilepsy
3. ๏ Antiphospholipid antibodies (aPL) are
directed against protein which binds to
phospholipids
- Beta2-glycoprotein I
- Protein C
- Annexin V
- Prothrombin
4.
5. Pathogenesis
aPL binds to n-terminal domain of Beta2-
glycoprotein I
Glycoprotein binds to phospholipid on surface
of endothelial cells, platelets, monocytes and
trophoblast
Alters function of those cells
Thrombosis / Miscarriage
6. Pathogenic clotting mechanisms mediated by aPL. aPL actions favor clot
formation through several routes.
(1) aPL interact with endothelial cells, primarily through binding of ฮฒ2GPI on the
cell surface, and induce a procoagulant and proinflammatory endothelial
phenotype.
(2) aPL upregulate tissue factor expression on endothelial cells and blood
monocytes, and promote endothelial leukocyte adhesion, cytokine secretion
and PGE2 synthesis.
(3) aPL recognize phospholipid-binding proteins expressed on plateletsโaPL
binding potentiates platelet aggregation induced by another agonist.
(4) aPL interfere with plasma components of the coagulation cascade, by
inhibiting anticoagulant activity, by affecting fibrinolysis, and by displacing the
binding of the natural anticoagulant annexin A5 to anionic structures. These
mechanisms all
contribute to a procoagulant state that is necessary but not sufficient for
clotting. Clot formation seems to require two steps: the presence of aPL
provides the โfirst hitโ, which produces clotting when accompanied by another
procoagulant condition, a
โsecond hitโ. Complement activation seems to be necessary for clot formation in
vivo. Abbreviations: aPL, anti-phospholipid
autoantibodies; ฮฒ2GPI, ฮฒ2 glycoprotein I; PGE2, prostaglandin E2
Pathogenesis of antiphospholipid syndrome: Understanding the antibodies
(PDF Download Available). Available from:
7. PRESENTATION
๏ Primary
๏ Secondary :SLE
RA
Systemic Sclerosis
Sjogrenโs syndrome
CAPS (Catastrophic APS): rapidly
progressing thromboembolic disease in
3 or more organs/ systems/ tissues
9. INVESTIGATIONS
๏ Anticardiolipin test
๏ Lupus Anticoagulant test
๏ Anti Beta2- glycoprotein 1 test
For confirmation of APS, test result
should be positive on at least 2 occasion
>= 12 weeks apart.
10. TREATMENT
๏ Warfarin used for life
๏ LMW heparin + Warfarin ๏ aim to keep
INR between 2.0 โ 3.0
๏ Warfarin + Aspirin (81 mg/ day)
๏ Aspirin reduces risk of thrombosis in aPL
positive individuals
๏ Pregnancy:
o Heparin + Aspirin
o IV immunoglobulin (IVlg) 400 mg/ kg
every day for 5 days may also prevent
abortions
11. TREATMENTโฆ
๏ Heparin-induced thrombocytopenia
and thrombosis syndrome: inhibitors
of phospholipid-bound activated factor
X (Fxa) ๏ fondaparinux 7.5 mg SC
daily or rivaroxaban 10 mg PO daily
๏ Effectiveness of clopidogrel and
hydroxychloroquine have not been
proven.
12. REFERENCEs
๏ Kumar and Clarkโs clinical medicine 8th
edition
๏ Davidsonโs Principles & Practices of
Medicine 21st edition
๏ Harrisonโs principal of internal medicine
19th edition
๏ https://www.researchgate.net/publication/
51111206_Pathogenesis_of_antiphospho
lipid_syndrome_Understanding_the_anti
bodies [accessed Apr 14, 2017].
๏ Bonnie et al; Treatment of
Antiphospholipid Syndrome; Up-To- Date
Editor's Notes
The major potential advantage of unfractionated heparin over LMW heparin is in the setting of hemorrhage (a rare complication of the APS). Unfractionated heparin can be reversed quickly with protamine, while LMW is not completely reversible with this approach.