Flashcards in 288b thrombocytopenia Deck (13):
SLE RBC antibody (anti-coagulation) effect? PTT test effect?
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)
aa from liver - stimulates c-Mpl receptor on megakaryocytes --> platelet production
TPO receptor pathway
receptor --> JAK-P (non-receptor tyrosine kinase) --> STAT pathway
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)
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
ITP - autoimmune thrombocytopenia - presentation?
bleeding --> petechiae, mucosal, intracranial hemorrhage
ITP - autoimmune thrombocytopenia - labs and dx?
clinical dx --> isolated thrombocytopenia - normal WBC, RBC count
Rituximab - target?
anti-CD20 antibody on B cells --> Fc-mediated B cell lysis
usually used for lymphoma
drug induced thrombocytopenia
drug induced platelet antibodies
Heparin induced thrombocytopenia (HIT) - pathogenesis?
PF4 from platelets + Heparin --> IgG autoantibodies --> thrombus + low platelets
Heparin induced thrombocytopenia (HIT) - Rx?
use direct thrombin inhibitor --> argatroban, lepirudin
Argatroban, bivalirudin - target? rx for what?
direct thrombin inhibitors
used for HIT