Bleeding and Bruising Scheme Flashcards
What is ITP and how does it work?
iatrogenic thrombocytopenia that is autoimmune mediated
Abs against GP IIb/IIIA -> no aggregation
complex removed by the spleen
what is DIC and how does it work?
thrombohemorrhagic act. by TF
usually preceded by an illness/trauma
leads to inc. thrombin
2 mechanisms for DIC?
thrombotic disorders-> clots
consumption of platelets and clotting factors-> bleeding
what lab tests do you expect with DIC>
inc. PT, aPTT, D-dimer,
dec. fibrinogen, platelets
schistocytes
what does an inhibitor mixing study tell you with PT, aPTT?
if it normalizes- factor def.
if it remains prolonged, inhibitor present (autoimmune)
what common drug can lead to a qualitative platelet disorder?
ASA
hemophilia A is a def. in which coag factor?
factor VIII
hemophilia B is a def. in which coag factor?
factor IX
what is the inheritance pattern of hemophilia?
x linked recessive
what is the mutation of TTP?
ADAMTS-13 ->vWF inc. (no breakdown)
what drugs cause thrombocytopenia?
penicillin, sulfonamides, phenytoin
pathophys of HIT?
heparin binds PF4 -> Ab binding to Fab region -> complex binding Fc region -> platelet activation -> thrombosis
what does lupus anticoagulant do?
interferes with clotting by inc. PTT
where is vWF stored?
weibel palade bodies
what coagulation factor is bound to vWF?
factor VIII
what gene codes for factor VIII
FA gene
what chr is responsible for vWF
Chr 12
what does SNP do in regards to vWF?
cleave vWF -> bleeding
which blood group has the highest vWF?
AB
genetics of Type 1 vWF def.
autosomal dominant
may not have family hx as incomplete penetrance
most common
point mutations -> red. secretion, and inc. clearance
haploinsufficiency
genetics of Type 2a vWF dz?
dominant missense mutation
full penetrance
genetics of Type 2b vWF dz?
gain of function ; autosomal dominant
full penetrance
vWF binds without collagen interaction
genetics Type 2M vWF dz?
autosomal dominant
fully penetrant
mutation in A3 domain
less platelet vWF interaction
genetics of type 2N vWF dz?\
autosomal recessive
red. VIII and so less vWF and VIII binding
hemophilia A
genetics of Type 3 vWF dz?
autosomal recessive
absence of vWF and dec. FVIII
what is used to treat vWF dz
desmopressin
stim. vWF release
which types of vWF dz do not respond to desmopressin
type 3, 2B, 2M, 2N
what cleaves/act FVIII
thrombin
FVIII is a cofactor for the cleavage of?
FX via IX
FIX is cleaved/act by?
FXI
what does FIX do?
cleaves/act. FX via FVIII
what inhibits FIX?
antithrombin
what test is useful for DIC?
D dimer
what is the first test you order when you have a prolonged PT or PTT
inhibitor mixing study
