section 11 - disorders of secondary hemostasis

Question 1

two primary mechanisms of primary fibrinolysis (fibrinogenolysis)

Answer 1

• over activation of plasmin
• overwhelming of plasmin inhibitors
  -> always pathological

Question 2

pathological causes of secondary fibrinolysis (fibrinolysis)

Answer 2

• ober activation of plasmin
• overwhelming of plasmin inhibitors
  -> normal or pathological

Question 3

name two causes of over activation of plasmin

Answer 3

• liver disease: decrease inhibitor production (alpha 2 antiplasmin)
• exogenous activators: streptokinase, urokinase, tPA

Question 4

name the test that can monitor plasmin over activation

Answer 4

euglobulin clot lysis
- qualitative measure of endogenous fibrinolytic capability

Question 5

describe anti-thrombin deficiency

Answer 5

• thrombosis
• hereditary w/ family history

Question 6

describe activated protein C resistance (APC-R)

Answer 6

• aka factor V leiden (FVL)
• mutation of factor V gene
• FV resistant to lysis or inactivation by activated protein C (APC)
• 20% of new thrombosis cases

Question 7

what results are expected of APC-R for PT and APTT

Answer 7

• both normal
• clot can form, just can’t break down

Question 8

how is APC-R tested for

Answer 8

• APTT + FV depleted plasma + pt plasma
• one tube gets normal calcium
• one tube gets calcium and APC
• APC-R will have norma Ca response and <49 second APC response

Question 9

describe how PK and HMWK deficiencies are found

Answer 9

• typically asymptomatic
• APTT prolonged
• may see thrombosis

Question 10

describe dysfibrinogenemia

Answer 10

• mostly asymptomatic
• may restsi fibrinogenolysis or once clot is formed resists fibrinolysis
• can present as bleeding or bleeding + thrombosis

Question 11

name the two types of plasminogen deficiencies

Answer 11

• type 1: decrease in activity and antigen -> deficiency
• type 2: dysfunctional plasminogen

Question 12

describe the prothrombin mutation

Answer 12

• point mutation
• increased prothrombin levels
• thrombosis

Question 13

describe how increased homocysteine impacts coagulation

Answer 13

• defect in homocysteine = increased
• damages endothelial cells = released TF3 = coagulation