Chapter 8: The Clotting Cycle & Bleeding disorders Flashcards
MCC of venous clots
stasis
MCC of arterial clots?
endothelial injury (exposure of BM)
MCC of genetic venous clots
Factor V Leiden defect
What is the normal PLT count?
150,000–350,000
All cells have MHC 1 on surface except which cells?
RBCs and PLTs (so they can set off immune system)
What is thrombocythemia?
When PLT count is 2 standard deviations above normal
What could cause secondary throbocytosis?
anemia, neoplasm, autoimmune disease, inflammation, infection
What could cause secondary thrombocytosis?
anemia, neoplasm, autoimmune disease, inflammation, infection
What is thrombotic thrombocytopenia purpura?
thrombotic microangiopathy due to vWF-esterase deficiency (ADAM TS 13); similar to DIC
What is microangiopathic Hemolytic Anemia (MAHA)?
When blood vessels have micro thrombus and causes passing RBCs to lyse
MCC of thrombocytopenia?
1)virus 2)drugs
What is immune thrombocytopenia?
When antibodies are made against PLTs; also called idiopathic thrombocytopenia purpura, immune thrombocytopenia purpura, and autoimmune thrombocytopenia purpura
What kinds of infection could cause thrombocytopenia?
Parvovirus B19; Hep C, Hep E
Do we transfuse for destructive process of PLTs?
NO, it will just be destroyed even more. Correct underlying problem or steroids
Which meds can cause thrombocytopenia?
AZT, benzene, chloramphenicol, vinblastine
What is heparin induced thrombocytopenia?
IgG attacks heparin after it forms a complex with Platelet Factor 4, usually occurs 3-10 days after initiating heparin therapy (HIT 2)
What is the difference between HIT 1 and HIT 2?
HIT 1 occurs due to PLT clumping within 48 hours (spleen removing PLTs); HIT 2 occurs 3-10 days after and involves IgG.
What is responsible for the “lucid” interval in epidural hematoma?
vasoconstriction
What are the 3 steps of Platelet plug?
1.platelet adhesion to injured vessel
2.platelet degranulation
3.platelet aggregation
What starts the platelet adhesion process?
endothelial injury exposes sub endothelial collagen, vWF binds to collagen, PLTs bind to vWF
What do platelets give off in degranulation?
Thromboxane A2, ADP and Ca
What does ADP do?
exposes GpIIb/IIIa so it can bind fibrinogen and provides energy for clumping process
What starts the platelet adhesion process?
endothelial injury exposes sub endothelial collagen, vWF binds to collagen, PLTs bind to vWF via GpIb
What is Bernard-Soullier syndrome?
defective GpIb (platelets don’t aggregate, prolonged bleeding)
What is Glanzmann thrombasthenia?
defective GpIIb/IIIa; platelets don’t aggregate, prolonged bleeding)
What does Prostaglandin I-1 do?
inhibits platelet aggregation; vasodilation
What does Prostaglandin E2 do?
vasodilation; decreases gastric secretion; increases gastric mucous secretion
What does prostaglandin F2a do?
bronchoconstriction, vasoconstriction, uterus contraction
What does TXA2 do?
platelet aggregation (aspirin irreversible inhibitor)
Which test is used to detect vWF or Bernard-Soullier?
ristocetin (add ristocetin to blood, no clumping)
What can you use to stop moderate bleeding in vWF, Bernard-Soullier, Glanzmann?
cryoprecipitate
What do you use for severe bleeding?
fresh frozen plasma (FFP)
Name a few ADP receptor blockers:
Clopidogrel, Ticagrelor, prasugrel
When are aspirin and clopidogrel used together?
In cardiac stenting; aspirin and clopidogrel for first 30 days; after that just aspirin
What do you use cilostazol for?
TTP first 2 weeks (inhibits TXA2 while increasing prostaglandin)
Name a GpIIb/IIIa inhibitor
abciximab
What is an irreversible TXA2 inhibitor?
aspirin
compartment syndrome 5 P’s
1.Pain out of proportion
2.Pallor
3.Paresthesia
4.Poikilothermia
5.Paralysis
What is Hemophilia A?
deficiency of Factor VIII
What lab is high in Hemophilia A?
PTT
What is Hemophilia B?
deficiency of Factor IX
What lab is high in Hemo B?
PTT
What do you do for mild bleeding of Hemophilia A?
DDAVP
What do you do for severe bleeding in Hemophilia A?
administer Factor VIII
What do you do for all bleeding Hemophilia B?
FFP
To stop passive hemorrhage (massive):
tranexamic acid
activated factor VII
activated prothrombin concentrate
activated fibrinogen complex concentrate
Direct thrombin inhibitors
argatroban, dabigatran
factor X inhibitors
rivaroxaban, apixaban
In which autoimmune disease is vWF blocked and intrinsic pathway stimulated (easy to clot)?
SLE, anticardiolipin
What is reflex sympathetic dysfunction from carpal tunnel syndrome?
severe autonomic discharge due to pain caused by NE (Tx: NE blocker phentolamine)
What is the earliest sign of Factor XIII defeciency?
recurrent umbilical stump bleeding
Skin necrosis upon administering warfarin
stop warfarin and give direct Factor X inhibitor
Why is there a two day bridge between heparin and warfarin?
because factor VII has a half-life of 2 days, hep blocks next thrombolytic after prot. C and antithrombin III
What should INR be for warfarin?
2-3 unless for metallic heart valves 2.5-3.5
