Coagulation & Platelet Disorders

Question 1

What does PT test?

Answer 1

Function of common & extrinsic pathway (factors I, II, V, VII, X). Inc in a defect

Question 2

What does PTT test?

Answer 2

Function of common & intrinstic pathway (all factors except VII & XIII). Inc in defect

Question 3

What is the MC coagulation disorder?

Answer 3

Hemophilia A

Question 4

What is increased in Hemophilia A or B?

Answer 4

PT

Question 5

What is the defect in Hemophilia A & B?

Answer 5

Intrinsic pathway coagulation defect

Question 6

What is deficient in Hemophilia A?

Answer 6

Factor VIII

Question 7

What is deficient in Hemophilia B?

Answer 7

Factor IX

Question 8

What are the sx of hemophilia A & B?

Answer 8

• Macrohemorrhages
• Hemarthroses (bleeding into joints)
• Easy bruising
• Inc PTT

Question 9

What is increased in Vitamin K?

Answer 9

PT & PTT

Question 10

What is the defect in Vitamin K def?

Answer 10

General coagulation defect

Question 11

Which factor synthesis is dec in Vitamin K def?

Answer 11

Factors II, VII, IX, X, protein C & S

Question 12

What do defects in platelet plug formation lead to?

Answer 12

Inc bleeding time (BT)

Question 13

What are the signs/sx of Platelet ABN?

Answer 13

• Microhemorrhage
• Mucous mem bleeding
• Epixtaxis
• Petechiae
• Purpura
• Inc bleeding time
• Possible dec platelet count (PC)

Question 14

What are the lab features of Bernard-Soulier synd?

Answer 14

• Dec platelet count
• Inc bleeding time

Question 15

What is the defect in Bernard-Soulier synd?

Answer 15

Platelet plug formation

Question 16

What is decreased in Bernard-Soulier synd?

Answer 16

Dec GpIb→ defect in platelet-to-vWF adhesion

Question 17

What are the lab features of Glanzmann’s thrombasthenia?

Answer 17

• Inc bleeding time
• Blood smear shows no platelet clumping

Question 18

What is the defect in Glanzmann’s thrombasthenia?

Answer 18

Defect in platelet plug formation

Question 19

What is decreased in Glanzmann’s thrombasthenia?

Answer 19

GpIIb/IIIa→ platelet-to-platelet aggregation

Question 20

What are the lab features in Idiopathic thrombocytopenic purpura (ITP)?

Answer 20

• Dec platelet count
• Inc bleeding time
• Inc megakaryocytes

Question 21

What is the defect in ITP?

Answer 21

Anti-GpIIb/IIIa Ab’s→ splenic macrophage, consumption of platelet/Ab complex

Question 22

What is dec in ITP?

Answer 22

Platelet survival

Question 23

What are the lab features of Thrombotic thombocytopenic purpura (TTP)?

Answer 23

• Dec platelet count
• Inc bleeding time
• Schistocytes
• Inc LDH

Question 24

What is deficient in TTP?

Answer 24

ADAMTS 13 (vWF metalloprotease)→ dec degradation of vWF multimers

Question 25

What is the pathogenesis of TTP?

Answer 25

Inc large vWF multimers→ inc platelet aggregation & thrombosis

Question 26

What is dec in TTP?

Answer 26

Platelet survival

Question 27

What are the sx of TTP?

Answer 27

* Neurologic sx * Renal sx * Fever * Thrombocytopenia * Microangiopathic hemolytic anemia

Question 28

What are the lab features in von Willebrand's dz?

Answer 28

* Inc bleeding time * Normal or inc PTT

Question 29

What is the intrinsic pathway coag defect in Von Willebrand dz?

Answer 29

Dec vWF→ normal or inc PTT (depends on severity; vWF acts to carry/protect factor VIII)

Question 30

What is the defect in platelet plug formation in von Willebrand's dz?

Answer 30

Dec vWF→ defect in platelet-to-vWF adhesion

Question 31

What is the MC inherited bleeding disorder?

Answer 31

von Willebrand's dz | (AD)

Question 32

How is von Willebrand's dz dx?

Answer 32

Ristocetin cofactor assay

Question 33

What is the tx of von Willebrand's dz?

Answer 33

DDAVP (desmopressin) which releases vWF stored in endothelium

Question 34

What are the test features in DIC?

Answer 34

* Dec platelet count * Inc bleeding time * Inc PT * Inc PTT

Question 35

What is DIC?

Answer 35

Widespread activation of clotting leads to a fef in clotting factors, which creates a bleeding state

Question 36

What are the causes of DIC?

Answer 36

* Sepsis (gram-neg) * Trauma * Obstetric complications * Acute pancreatitis * Malignancy * Nephrotic synd

Question 37

What are the lab features in DIC?

Answer 37

* Schistocytes * Inc fibrin split products (D-dimers) * Dec fibrinogen * Dec factors V & VIII

Question 38

What is Factor V Leiden dz?

Answer 38

Production of mutant factor V that is resistant to degradation by activated protein C

Question 39

What is the MCC of inherited hypercoagulability in whites?

Answer 39

Factor V Leiden dz

Question 40

What is Prothrombin gene mutation?

Answer 40

Mutation in 3' untranslated region→ inc production of prothrombin→ inc plasma levels & venous clots

Question 41

What is Antihrombind def?

Answer 41

Inherited def of antithrombin

Question 42

What is blunted after heparin administration in Antithrombin def?

Answer 42

Inc in PTT

Question 43

What is Protein C or S def?

Answer 43

Dec ability to inactivate factors V & VIII

Question 44

What does Protein C or S def inc risk of?

Answer 44

Thrombotic skin necrosis w/ hemorrhage following administration of warfarin

Question 45

What is the dosage effect of Packed RBCs?

Answer 45

Inc Hb & O2 carrying capacity

Question 46

What is the clinical use of Packed RBC's?

Answer 46

* Acute blood loss * Severe anemia

Question 47

What is the dosage effect of Platelets?

Answer 47

Inc platelet count (Inc -5,000/mm³/unit)

Question 48

What is the clinical use of Platelets?

Answer 48

Stop significant bleeding (thrombocytopenia, qualitative platelet defects)

Question 49

What is the dosage effect of Fresh frozen plasma?

Answer 49

Inc coagulation factor levels

Question 50

What are the clinical uses for Fresh frozen plasma?

Answer 50

* DIC * Cirrhosis * Warfarin overdose

Question 51

What is the dosage effect of Cryoprecipitate?

Answer 51

Contains fibrinogen, factor VIII, factor XIII, vWF & fibronectin

Question 52

What are the clinical uses of Cyroprecipitate?

Answer 52

Tx coagulation factor def involving fibrinogen & factor VIII

Question 53

What are the risks of blood transfusion?

Answer 53

* Include infection transmission (low) * Transfusion reactions * Iron overload * Hypocalcemia (citrate is a Ca chelator) * Hyperkalemia (RBC may lyse in old blood unit)