Clotting cascade

Question 1

Primary hemostasis

Answer 1

Platelets form clot with weak plug

1) Endothelian release for contraction
2) vWF bind to exposed collagen via GP1B for platelet adhesion
3) ADP and TXA2 released after binding
4) Aggregation via Gp2b3a

Question 2

Secondary hemostasis

Answer 2

Stabilize clot

Question 3

vWF

Answer 3

Made by endothelium and some from platelet

ET also has Weibel-Palade body (willebrand and p-selectin)

Question 4

ADP in RBC

Answer 4

Causes expression of Gp2b3a on platelet to induce aggregation

Question 5

Primary hemostasis disorders

Answer 5

Quantitative (Petechia from thrombocytopenia) and qualitative
Mucosal and skin bleeding

Question 6

ITP (Ideiopathic thrombocytopenic purpura

Answer 6

Autoimmunce of IgG against platelets GP2b3a
Most common for thrombocytopenia

Low platelets, hyperplasia of megakaryocytes

Tx: corticosteroids
Primary hemostatic problem

Question 7

Microangiopathic hemolytic anemia

Answer 7

Small vessels platelet formation
Causes schistocyte/lysed RBCs
Primary hemostatic problem
Two causes TTP and HUS

Question 8

TTP

Answer 8

Thrombotic thrombocytopenic purpura
Adamsts13 deficiency which cleaved vWF to lead to degredation.
Can have auto Ab against Adamsts13 or genetic. Classic female Pt.
Also schistocytes
PT/PTT normal

Tx: plasmapheresis and steroids

Question 9

HUS

Answer 9

Hemolytic uremic Syndrome
Mostly in kidney because of infection from E. coli O157H7 verotoxin
From undercooked beef with dysentery
Microthrombi and Schistocytes made
PT/PTT normal

Question 10

TTP and HUS findings

Answer 10

Bleeding
Microangiopathic hemolytic anemia
Fever
Renal insufficiency
CNS abnormalities

Both are quantitative

Question 11

Bernard soulier syndrome

Answer 11

Genetic GP1b deficiency and platelet adhesion is impaired.
Get enlarged and mild thrombocytopena
Qualitative

Question 12

Glanzmann thrombastheniaa

Answer 12

G2b3a difficiency, aggregation impaired

Qualitative

Question 13

Cox inhibitor ASA

Answer 13

Irreversible binding of ASA to COX so no TXA2 production

Question 14

Uremia

Answer 14

Poor kidney function disrupts adhesion and aggregation

Question 15

Secondary hemostasis disorders

Think elevated PTT

Answer 15

Abs against factors (F8 most common)
vWF- (stabilizes F8), presents like primary, treat with desmopressin to increase vWF from weibel-palade ET cells
Hemophilia A- F8
Hemophilia B- F9
Vit K- y-carboxylation on F2/7/9/10,C,S
Liver- Decrease factors, less epoxide reductase
   Trend with PT values
Large volume transfusions dilute factors

Question 16

Primary hemostatsis disorders

Answer 16

ITP
HUS
TTP
Bernard soulier syndrome
Glanzmann thrombasthenia
Cox inhibitors
Uremia