September 1, 2015 - Heme Flipped Classroom 1

Question 1

Primary Hemostasis

Answer 1

Part of the process of blood clot formation.

Involves the adhesion, activation, and aggregation of platelets combined with von Willebrand factor to produce a temporary platelet plug.

Question 2

Secondary Hemostasis

Answer 2

Part of the blood clot formation process.

Activation of coagulation factors (extrinsic, intrinsic, and common pathways) to produce a stable fibrin clot.

Question 3

Regulation of Coagulation System

Answer 3

The coagulation system and clot production is regulated by the anticoagulation system (Tissue factor pathway inhibitor, antithrombin, Protein C and Protein S)

Question 4

Fibrinolytic System

Answer 4

Composed of plasminogen and t-PA.

Removes unwanted fibrin clots and restores blood vessel patency once the vascular injury has healed.

Question 5

Idiopathic Thrombocytopenic Purpura (ITP)

Answer 5

ITP is an autoimmune disease which antibodies detectable against platelet surface antigens. May be acute, or chronic.

Treatment is steroids.

Question 6

Heparin-Induced Thrombocytopenia

Answer 6

Exposure to heparin within the past 5-10 days causes antibodies to attack platelets.

Question 7

Glanzmann’s Thrombasthenia

Answer 7

Failure of platelet aggregation because of a lack of membrane receptors GPIIb/IIIa.

In the presence of normal plasma levels of fibrinogen, they have a decreased aggregation of platelets to each other (prolonged bleeding time / closure time).

Question 8

Bernard Soulier Syndrome

Answer 8

A congenital platelet with adhesion defects.

Platelets lack membrane receptors (GP1b) for von Willebrand factor. In the presence of normal plasma levels of von Willebrand factor, there is a decreased adhesion of platelets to subendothelium (prolonged bleeding / closure time).

Question 9

Platelet Function Defects - Congenital

Answer 9

These are rare, but should be considered.

Most platelet function defects are commonly acquired due to medication effects.

Question 10

Vitamin K Deficiency

Answer 10

Can be a cause of an elevated PT.

Question 11

Hemorrhagic Disease of the Newborn

Answer 11

A disease caused by insufficient Vitamin K in newborns.

Question 12

PT Test

Answer 12

Used to assess Factor VII (extrinsic pathway) and Factors II, V, X and Fibrinogen (common pathway)

Major causes of an isolated PT include Factor VII deficiency and warfarin therapy.

Question 13

VWD

Answer 13

Type 1 VWD - Equal reductions in VWF Activity and VWF Antigen. FVIII may be normal or low.

Type 2 VWD - Greater reduction in VWF activity when compared with the reduction in VWF antigen (ratio of VWF activity to antigen <0.5-0.7). Factor VIII may be normal or low.

Type 3 VWD - Extremely low or undetectable levels of VWF antigen and activity. FVIII often <10% of normal.