Hem 1 - Clotting Factors

Question 1

Where are coagulation factors made?

Answer 1

Liver.

Question 2

What coagulation factor starts with coagulation factor 12?

Answer 2

Intrinsic (contact activation form).

Question 3

What coagulation factor starts with coagulation factor 7?

Answer 3

Extrinsic (tissue factor pathway; thromboplastin).

Question 4

What happens when you are deficient in coagulation factor 9?

Answer 4

Hemophilia B.

Question 5

What happens when you are deficient in coagulation factor 8?

Answer 5

Hemophilia A. [A sounds like eight]

Question 6

What is the rate limiter of the coagulation cascade?

Answer 6

Factor 10, where extrinsic and intrinsic factors meet.

Question 7

What are the excelirating coagulation factors? Which substances inhibit them?

Answer 7

Factor 8 and factor 5. Protein C and Protein S inhibit them, breaking clots down.

Question 8

What coagulation factors are inhibited by warfarin?

Answer 8

Factors 2, 7, 9, 10. It also inhibits the production of Protein C and S, causing transiently increases clot formation.

Question 9

What is another name for Prothrombin? For Thrombin?

Answer 9

Prothrombin is factor 2. Thrombin is facto 2a.

Question 10

Which substance inhibits the transformation of prothrombin to thrombin?

Answer 10

Antithrombin.

Question 11

How does Heparin work?

Answer 11

It increases the effectiveness of antithrombin.

Question 12

What other substance besides thrombin, what other biological substance can covert fibrinogem to fibrin?

Answer 12

Coagulase.

Question 13

What kind of process is the crosslinking of fibrin?

Answer 13

Covalent process.

Question 14

What ion is essential for the coagulation cascade?

Answer 14

Calcium.

Question 15

If we use calcium binders, it takes up a lot of calcium and reduces coagulation because calcium is essential in the coagulation cascade. What are some calcium binders?

Answer 15

Trisodium citrate. EDTA.

Question 16

What are the two functions of Factor 12a?

Answer 16

It activates the coagulation cascade and the fibrinolytic system. Activates factor 11. Convert prekallikrein to kallikrein (kallikrein cleaves plasminogen to form plasmin).

Question 17

What does plasmin do?

Answer 17

It breaks down the fibrin mesh.

Question 18

What are the 2 functions of Kallikrein?

Answer 18

Kallikrein cleaves plasminogen to form plasmin. Also converts high molecular-weight kininogen (HMWK) to bradykinin.

Question 19

What are the three functions of Bradykinin?

Answer 19

Vasodilator. Increases vascular permeability. Mediator of pain.

Question 20

Why can patients taking ACE inhibitors develop edema?

Answer 20

Because Angiotensin converting enzyme (ACE) is responsible for degrading bradykinin (which is a vasodilator and increases vascular permeability). An inhibitor of ACE would leave a lot of bradykinin around, leading to angioedema.

Question 21

What is Prothromobin time (PT)?

Answer 21

When you take some of the patient’s plasma and add tissue factor, and you measure how long it takes to clot to form. Normally takes 10 to 13 secs: Measures how effectively tissue factor can activate the tissue facto pathway and the final common pathway. This tests factors 7, 10, 5, and prothrombin (factor 2). Always reported with an INR.

Question 22

What is INR?

Answer 22

International normalizing ratio, always reported w/ PT to account for the discrepancies of labs. An INR of 1 is normal; anything higher means the patient’s blood is taking longer to coagulate.

Question 23

What is PTT?

Answer 23

Partial thromboplastin time, takes the patient’s plasma and adding material that activates the contact activation pathway (like silica) and measures how long it takes to clot. Normally it is 25 to 40 secs. It test for function of the contact activation pathway and the final common pathway; tests for factors 12, 11, 9, and 8. Also factors 10, 5, and prothrombin.

Question 24

What is Bleeding time?

Answer 24

Cut the patient and keep wiping the blood away to see how long it stops bleeding. Takes 2 to 9 minutes. It measures the function of platelets (does not measure coagulation factor at all, therefore disorders of the coagulation cascade wont affect the bleeding time).

Question 25

How would PTT, PT and INR be affected in someone with hemophilia?

Answer 25

PTT will be increased. No effect on PT or INR.

Question 26

What are the vitamin K dependent clotting factors?

Answer 26

[diSCo started in 1972] Coagulation factors 2, 7, 9, 10. Also protein C and S.

Question 27

How would PT and PTT be in someone with vitamin K deficiency?

Answer 27

Both will be elevated.

Question 28

What are the causes of vitamin K deficiency.

Answer 28

Someone who isn’t taking in enough vitamin K. Newborns. Patients on warfarin.

Question 29

What disease accounts for 40 to 50% of all inherited hypercoagulable states?

Answer 29

Factor 5 Leiden.

Question 30

What is Factor 5 Leiden?

Answer 30

A disease causing hypercoagulable state, it is mutation that makes factor 5a resistant to inactivation by protein C, therefore factor 5 stays active longer, leading to increased coagulation. AKA activated protein C resistance.

Question 31

What does Prothrombin G20210A mutation cause?

Answer 31

Predisposes to thrombosis. It is a mutation of guanine to adenine at the 20210 position of the prothrombin gene.

Question 32

What does Antithrombin deficiency cause?

Answer 32

Unable to inactivate thrombin, leading to a hypercoagulable state.

Question 33

What does Protein C deficiency cause?

Answer 33

Unable to inactivate factors 5 and 8,leading to a hypercoagulable state.

Question 34

What coagulation factor is deficient in hemophilia A?

Answer 34

Factor 8.

Question 35

What coagulation factor is deficient in hemophilia B?

Answer 35

Factor 9.

Question 36

What is the clinical consequence of a deficiency in either protein C or protein S?

Answer 36

Both are anticoagulants, therefore leads to a hypercoagulable state.