Hemostasis and Related Disorders Flashcards
What molecule mediates the transient vasoconstriction of primary hemostasis? What cell type releases this molecule?
endothelin
endothelial cells
What clotting factor binds subendothelial collagen?
vWF
Platelets bind vWF via what receptor?
GpIb
What two molecules are contained within Weibel Palade bodies?
vWF and P-selectin
What is contained in dense granules? What cell type?
ADP and calcium
platelets
GpIIb/IIIa is upregulated on the surface of platelets by what signal?
ADP binding ADP receptor
What molecule binds to GpIIb/IIIa?
fibrinogen
What are petechiae indicative of?
thrombocytopenia
What is a normal platelet count? Below what level can lead to petechiae?
150 - 400
What isotype of immunoglobulin is produced during Immune Thrombocytopenia? Against what?
IgG
GpIIb/IIIa
What cell type produces the Ab during Immune Thrombocytopenia? What organ is this cell located? What organ consumes these RBCs?
Plasma cells
spleen
spleen
Acute Immune Thrombocytopenia arises in what patient population? After what two happenings?
children
viral infection or vaccination
Chronic Immune Thrombocytopenia arises in what patient population?
women of childbearing age
Are any coagulation factors affected during Immune Thrombocytopenia? Why?
no . only destruction of GpIIb/IIIa
What is the initial treatment of Immune Thrombocytopenia?
corticosteroids = initial Tx
What two reasons is a splenectomy used as treatment for Immune Thrombocytopenia?
removes source of auto-Ab (splenic plasma)
removes site of platelet destruction (splenic macrophages)
What is microangiopathic hemolytic anemia?
pathological formation of platelet microthrombi in small vessels
What cellular happening is seen during MAHA?
schistocytes
What are the two classic disorders that will produce Microangiopathic Hemolytic Anemia?
TTP and HUS
Lack of what enzyme causes TTP? What is the normal function of this enzyme?
ADAMTS13
cleave vWF
What patient population most often develops auto-ADMATS13 Ab’s?
adult female
What specifc bacterial strain produces HUS? Where is this strain found?
E. coli O157:H7
undercooked beef
Does HUS cause renal or CNS defects?
renal
Does TTP cause renal or CNS defects?
CNS
Are coagulation factors effected during HUS or TTP? What does this mean?
no
PT/PTT = normal
What cellular happening is observed during TTP/HUS?
schistocytes
What would be observed on a bone marrow biopsy of during TTP/HUS?
schistocytes
What are the two treatments of TTP and HUS?
plasmapheresis and corticosteroids
What is defective/absent during Bernard-Soulier syndrome? What is impaired?
GpIb
adhesion = impaired
What two cellular happenings are seen during during Bernard-Soulier syndrome?
mild thrombocytopenia and enlarged platelets
What is defective during Glanzmann thrombasthenia? What is impaired?
GpIIb/IIIa
aggregation = impaired
What activates factor VII?
tissue thromboplastin
What activates factor XII?
subendothelial collagen
Defects in primary homeostasis manifest as what? Where?
skin and mucosal bleeding
nose bleeds (Epistaxis)
Defects in secondary homeostasis manifest as what two conditions?
deep tissue bleeding
rebleeding after surgical procedures
PT measures which arm of the coagulation cascade?
extrinsic
Which clotting factors does PT measure?
I (fibrinogen), two, five, seven and ten
PTT measures which arm of the coagulation cascade?
intrinsic
What is the mode of inheritance of hemophilia A?
X-linked recessive
What are of the coagulation cascade would be effected during hemophilia A?
PTT
What coagulation factor is absent during Hemophilia B?
nine
What coagulation factor is most likely to develop an autoantibody against it? How would this be diagnosed?
eight
PTT does not correct upon mixing with normal serum
Will PTT be corrected if a patient with Hemophilia A is given normal serum?
yes
Will PTT be corrected if a patient with Coagulation Factor Inhibitor is given normal serum?
no
What two sites will bleed during vWF Disease?
skin and mucosa
What branch of the coagulation cascade will vWF Disease effect? Why?
PTT
vWF binds and protects factor eight
What drug is used to Dx vWF Disease? What is the MOA of this drug?
Ristocetin
causes vWF to bind GpIb
What drug is used to Tx vWF Disease? What is the MOA of this drug?
Desmopressin (DDAVP)
desmopressin causes endothelial cells to release vWF from Weibel-Palade bodies
What factors are regenerated by Vitamin K?
two, seven, nine, ten, C and S
What branch of the coagulation cascade is used to follow liver failure?
PT
What protein do platelets bind during HIT?
PF4
What isotype of Ab is involved during HIT?
PF4
What pro-coagulant is contained in amniotic fluid?
tissue thromboplastin
What two bacteria are the most common causes of septic DIC?
E. coli
N. meningitidis
Why does sepsis cause DIC? Why?
endotoxin
influences endothelial cells to make tissue factor
What coagulation factor is tissue factor?
III
What type of neoplasia can result in DIC? What specific product causes this?
adenocarcinoma
mucin
What type of leukemia can cause DIC? Why?
acute promyelocytic leukemia
primary granules
What type of bite can cause DIC?
rattlesnake
What is the serologic marker for DIC? What is D-Dimer derived from?
D_DIMER
fibrin split products
What surgery can cause a disorder of fibrinolysis? Why?
radical prostatectomy
release of urokinase
What if the function of urokinase?
activate plasmin
Why can liver failure result with a defect in fibrinolysis?
decrease production of α2 anti-plasmin during liver failure
Why do errors in fibrinolysis produce an increase in PT and PTT?
plasmin degrades coagulation factors
Is the platelet count normal during errors of fibrinolysis?
yes
What is the Tx of disorders of fibrinolysis? What is the MOA of this drug?
aminocaproic acid
blocks activation of plasminogen