Hematopathology III

Question 1

What are hemorrhagic diatheses?

Answer 1

Disorders characterized by abnormal bleeding (spontanous or following trauma or surgery)

Question 2

Hemorrhagic diatheses can be due to possible defect in what 3 factors that control bleeding?

Answer 2

• Integrity of blood vessel wall
• Platelet function
• Clotting cascade to produce fibrin mesh

Question 3

Describe the bleeding time test

Answer 3

Time for a standardized skin puncture to stop bleeding. Clinical measure of platelet function

Question 4

What is a normal platelet count?

Answer 4

150,000-450,000 /uL

Question 5

What does prothrombin time measure?

Answer 5

Extrinsic and common pathways

Question 6

How is prothrombin time used?

Answer 6

Tissue thromboplastin and Ca2+ added to blood

Question 7

What does a partial thromboplastin time measure?

Answer 7

Intrinsic and common pathways?

Question 8

How is partial thromboplastin time used?

Answer 8

Kaolin, phospholipid and Ca2+ added to blood

Question 9

What do you call a low platelet count?

Answer 9

Throbocytopenia

Question 10

What can cause thrombocytopenia?

Answer 10

Drugs, infections, aplastic anemia, metastasis, leukemias, autoimmune

Question 11

Thrombocytopenia occurs mainly by decrease in

Answer 11

Production, can also be accelerated destruction

Question 12

What are inherited qualitative defects in platelet function?

Answer 12

• Bernard- Soulier syndrome
• Glanzmann’s thrombasthenia

Question 13

What is Bernard-Soulier syndrome?

Answer 13

GPIb-V-IX glycoproteins are missing or defective

Question 14

What is Glansmann’s thrombasthenia?

Answer 14

GPIIb-IIIa glycoproteins are missing or defective

Question 15

What are signs and symtpoms of platelet disorders?

Answer 15

-Petechiae and ecchymoses, easy bruising
- Epistaxis, excessive bleeding from minor trauma
- Menorrhagia

Question 16

Lab results of platelet disorders

Answer 16

PTT and PT normal, bleeding time is prolonged

Question 17

Lab test results from disorders causing increased fragility of vessels

Answer 17

Normal PT and PTT, normal platelet count

Question 18

Coagulation disorders lab results

Answer 18

PT, PTT or both are prolonged depending on deficiency. Bleeding time is normal (petechiae usually absent)

Question 19

What are acquired coagulation disorders?

Answer 19

• Vitamin K deficiency: prothrombin (II), VII, IX< X
• Liver diseases: decreased clotting factor synthesis

Question 20

What are hereditary coagulation disorders?

Answer 20

Factor VIII and/or other factor deficiencies

Question 21

What can occur from a coagulation disorder following operative procedures?

Answer 21

Massive hemorrhage

Question 22

Coagulation disorders can cause

Answer 22

Internal hemorrhages, intramuscular and joint bleeds

Question 23

Hemophilia A is a deficiency of what?

Answer 23

VIII

Question 24

Hemophilia A is X-linked recessive, therefore confined to

Answer 24

Males or homozygous females

Question 25

Characteristics of Hemophilia A

Answer 25

- 30% cases have no family history - Severe bleeding when VIII <1% - Most cases are due to quantitative decrease in VIII or a qualitative defect so it is ineffective

Question 26

What is treatment for hemophilia A?

Answer 26

Infusion of recombinant factor VIII

Question 27

Hemophilia B is a deficiency of what?

Answer 27

IX

Question 28

What is the treatment of hemophilia B?

Answer 28

Infusion of recombinant IX

Question 29

vWF is a multimer adhesive glycoprotein that plays a major role in what?

Answer 29

Hemostasis by mediating platelet adhesion

Question 30

Where is vWF synthesized?

Answer 30

In endothelial cells and megakaryocytes

Question 31

vWF is present in what?

Answer 31

Subendothelial connective tissue and is exposed with damage to endothelial cells (serves to bind platelets to site of damage)

Question 32

vWF is autosomal

Answer 32

dominant

Question 33

What does vWF do?

Answer 33

Binds and stabilized factor VIII

Question 34

Laboratory tests of disseminated intravascular coagulation

Answer 34

Bleeding time, PT, PTT are all prolonged - D-dimers - Consumptive coagulopathy

Question 35

How is disseminated intravascular coagulation treated?

Answer 35

Tx underlying disorder, use of coagulants and anticoagulants is required

Question 36

In cancer patients, chronic DIC is dominated clinically by

Answer 36

the thrombotic complications

Question 37

In obstetric complications, acute DIC is dominated clinically by

Answer 37

the bleeding diathesis

Question 38

What is the mechanism of DIC?

Answer 38

- Release of tissue factor into circulation - Widespread injury to endothelial cells

Question 39

Tissue factor into circulation in DIC

Answer 39

- Placental tissue in obstetric complications - Dying leukemic cells - Carcinoma cells - Monocytes secreting them via eco/endotoxins

Question 40

Describe endothelial damage of DIC

Answer 40

Antigen-antibody complexes, exotoxins, major trauma