Coagulation Flashcards
What changes in coagulation do you see with cirrhosis?
Increase PT/PTT b/c it can’t make the coagulation factors as well. Also can’t make Protein C & S
What are the things that factor 12a converts?
11-11a (pro-clot forming)
prekallikrein–>kallikrein (anti-clot forming)
Describe what happens once you get kallikrein?
you get conversion of plasminogen–>plasmin (clot buster of fibrin mesh)
and you convert HMWK–>bradykinin
What are the functions of bradykinin?
- increase vascular permeability
- vasodilation
- pain
What are some factors that are important for coagulation?
phospholipids
Ca++
**give anti-Ca++ stuff for bags of blood to prevent clotting
What types of bonds are seen in the fibrin mesh?
covalent bonds
What do streptokinase and tpA do?
increase conversion of plasminogen to plasmin
What does aminocaproic acid do?
inhibits conversion to plasmin
What is heparin’s MOA?
it stimulates anti-thrombin. which acts on factor 2a
What are the accelerating factors of the coagulation cascade? What inhibits them?
8a, 5a
inhibited by Proteins C&S
What is the rate-limiting step of the coag cascade?
10–>10a
What does s. aureus do to coag cascade?
its coagulase enzyme converts fibrinogen–>fibrin
What does PT test?
add tissue factor
tests extrinsic and common pathways
7, 10, 5, 2
should be roughly 10-13s
What is the purpose of the INR?
international normalized ratio
INR=1 is normal
INR>1 long time to clot! Deficiency of a factor somewhere perhaps
What does the PTT test tell?
add phospholipid and silica
tests internal pathway and common pathway
12, 11, 9, 8, 10, 5, 2
should be 25-40s
What is bleeding time?
cut a pt and see how long they bleed, should be 2-9 minutes
measure of platelet function, NOT coag cascade
hemophilia A, B, C are deficiencies of which factors? What do they do to PT/PTT?
A-8. X-linked recessive
B-9 X-linked recessive
C-11 autosomal recessive
increase PTT, not PT
What’s the deal with Vit K deficiency?
decrease in Proteins C, S, 2, 7, 9, 10
bleeding time normal
PT and PTT increased
Which patients do you see VIt K deficiency in?
Newborns–don’t have gut flora to make
Warfarin (too much)
End stage liver dx–can’t make clotting factors and proteins
What’s the deal with antithrombin deficiency?
Heparin has little effect on PTT
Can be genetic or from nephrotic syndrome and loss of antithrombin in urine
not really abnormal PT, PTT otherwise
Hypercoagulable
What’s the deal with Factor V Leiden?
Protein C can’t inhibit this V
hypercoagulable
What’s the deal with Protein C or S deficiency?
can’t inhibit 5a, 8a
after warfarin admin, sometimes get skin and subcu tissue necrosis
What’s the deal with Prothrombin Gene mutation?
G20210A. Guanine–>Adenine. think 90210
mutation in 3’ untranslated region
increased production of prothrombin.
hypercoagulable
