MHD: Abnormal Hemostasis

Question 1

What are the two general categories of platelet disorders?

Answer 1

Quantitative

Qualitative

Question 2

What is thrombocytopenia?

Answer 2

Decreased platelet count leading to bleeding

Question 3

What is thrombocytosis?

Answer 3

A benign increase in platelet count

Can cause bleeding or thrombosis

Question 4

What is thrombocythemia?

Answer 4

A neoplastic clonal proliferation of platelets

Can cause bleeding or thrombosis

Question 5

What can cause thrombocytopenia?

Answer 5

Bone marrow alterations (cancer)
Hereditary defects
Abnormal hematopoiesis (folate deficiency)
Drugs (heparin, sulfonamides ...etc.)
Dilutional (dialysis)

Question 6

How does heparin induced thrombocytopenia occur?

Answer 6

Complexes of Heparin and PF4 form

Autoantibodies lead to destruction of platelets leading to thrombosis

Question 7

What are the two categories of thrombocytopenic purpura?

Answer 7

Immune thrombocytic purpura (ITP)

Thrombotic thrombocytic purpura (TTP)

Question 8

What role does the spleen play in ITP?

Answer 8

The splenic plasma cells produce IgG against platelet antigens
Splenic macrophages digest antibody bound platelets.
Cure for ITP: splenectomy

Question 9

What are the causes of thrombocytosis?

Answer 9

Splenectomy
Reactive thrombocytosis (cancer, infection, or drug induced)
Autonomous thrombocytosis

Question 10

What are the three inducers of qualitative platelet disorders?

Answer 10

Disease (liver disorders)
Drugs (aspirin, NSAIDS)
Diet (omega 3 fatty acids)

Question 11

What are the inherited qualitative platelet disorders?

Answer 11

Glanzmann’s thrombasthemia (GPIIb/IIIa defect)

Bernard-Soulier disease (GPIb defect)

Question 12

What is non-thrombocytopenic purpura?

Answer 12

Vascular disorders leading to easy bruising, bleeding, purpura, vasculitis with normal platelet function and coagulation

Question 13

What is the most common congenital endothelial disorder?

Answer 13

Hereditary hemorrhagic telangiectasia (HHT)

Question 14

What is the main nutritional disorder that can cause bleeding?

Answer 14

Scurvy, vitamin C deficiency

Question 15

What are the two coagulation defects associated with the intrinsic pathway?

Answer 15

Hemophilia A (VIII)
Hemophilia B (IX)

Question 16

What type of inheritance do the hemophilias have?

Answer 16

Sex linked recessive

Question 17

What is the most common inherited coagulation disorder?

Answer 17

Von willebrand disease: genetic vWF deficiency

Question 18

What lab tests can distinguish hemophilia from VWD?

Answer 18

In hemophilias, bleeding time is unchanged whereas bleeding time is elevated in VWD

Question 19

Describe primary fibrinolysis

Answer 19

Excessive fibrinolysis leads to bleeding because fibrinogen levels are decreased

Question 20

What is another name for secondary fibrinolysis?

Answer 20

Disseminated intravascular coagulation (DIC)

Question 21

What processes occur during DIC?

Answer 21

DIC is associated with fibrinolysis and coagulation

Question 22

What is the hallmark test used for DIC?

Answer 22

D-dimer test: looks for fibrin split products

Question 23

Describe the pathogenesis of sepsis associated DIC

Answer 23

Tissue destruction and sepsis lead to the release of tissue factor, which causes widespread thrombosis.

Thrombosis leads to decreased platelets and activated plasmin (both leading to increased bleeding)

Question 24

What is the result of α2-antiplasmin deficiency?

Answer 24

Bleeding

Increased fibrinolysis due to an inability to inhibit plasmin