288b thrombocytopenia Flashcards Preview

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Flashcards in 288b thrombocytopenia Deck (13):
1

SLE RBC antibody (anti-coagulation) effect? PTT test effect?

causing clotting

increases PTT, mixing test doesn't fix - opposite effect of antibody against F VIII (which causes bleeding and increased PTT plus a low F VIII)

2

thrombopoietin (TPO)

aa from liver - stimulates c-Mpl receptor on megakaryocytes --> platelet production

3

TPO receptor pathway

receptor --> JAK-P (non-receptor tyrosine kinase) --> STAT pathway

4

ITP - autoimmune thrombocytopenia - what is the pathogenesis?

CD4+ t-cells detect GP IIb/IIIa on platelet membrane -->

B cells produce IgG autoantibodies -->

platelet destruction via Mo in speel and liver (can remove spleen for Rx)

5

ITP - autoimmune thrombocytopenia - acute vs chronic?

acute - kids, virus infection --> cross reacting Ab

chronic - adults, idiopathic usually but can be HIV, Hep C, H pylori

6

ITP - autoimmune thrombocytopenia - presentation?

bleeding --> petechiae, mucosal, intracranial hemorrhage

7

ITP - autoimmune thrombocytopenia - labs and dx?

clinical dx --> isolated thrombocytopenia - normal WBC, RBC count

8

Rituximab - target?

anti-CD20 antibody on B cells --> Fc-mediated B cell lysis

usually used for lymphoma

9

drug induced thrombocytopenia

chemo drugs

drug induced platelet antibodies

HIT

10

Heparin induced thrombocytopenia (HIT) - pathogenesis?

PF4 from platelets + Heparin --> IgG autoantibodies --> thrombus + low platelets

11

Heparin induced thrombocytopenia (HIT) - Rx?

discontinue heparin/LMWH

use direct thrombin inhibitor --> argatroban, lepirudin

12

Argatroban, bivalirudin - target? rx for what?

direct thrombin inhibitors

used for HIT

13

Romiplostim?

TPO receptor agonist --> increases platelet production