Haemostasis V: Thrombotic Disorders (DVT, Pulmonary Embolism)

Question 1

What is thrombophilia?

Answer 1

Thrombophilia is a genetically determined increased likelihood of thrombosis.

Question 2

What is the incidence of venous thromboembolism?

Answer 2

The incidence of venous thromboembolism is approximately 1 per 1000 annually.

Question 3

Which thrombotic disorder commonly arises from proximal DVT?

Answer 3

Most pulmonary emboli arise from proximal DVT in the popliteal, femoral, and iliac veins.

Question 4

Name three common forms of thrombophilia.

Answer 4

Common forms of thrombophilia include Factor V Leiden, Prothrombin G20210A, and increased VIII levels.

Question 5

Name two rare forms of thrombophilia.

Answer 5

Rare forms of thrombophilia include Protein C deficiency and Protein S deficiency.

Question 6

What are the clinical features of DVT with gangrene?

Answer 6

Clinical features of DVT with gangrene include swelling, erythema, and discoloration.

Question 7

What are the objectives of treatment for venous thromboembolism?

Answer 7

The objectives of treatment are to prevent death from pulmonary embolism, prevent morbidity from venous thromboembolism, and minimize post-thrombotic syndrome.

Question 8

What imaging modality is used to diagnose DVT?

Answer 8

Doppler ultrasonography is used to diagnose DVT.

Question 9

What are the steps in the diagnosis of DVT?

Answer 9

Diagnosis of DVT involves clinical history and examination, Doppler ultrasonography, venography, plasma D-dimer, clotting profile, chest USS, spiral CT, pulmonary angiography, and tests for thrombophilias.

Question 10

Name three treatment options for anticoagulant therapy.

Answer 10

Treatment options include standard heparin (UFH), low molecular weight heparin, and oral anticoagulants.

Question 11

What is the role of an inferior vena cava filter in thrombosis management?

Answer 11

An inferior vena cava filter is used in patients with acute DVT who have an absolute contraindication for anticoagulation.

Question 12

What is the function of fibrinolysis?

Answer 12

Fibrinolysis plays a role in the dissolution of blood clots and maintenance of a patent vascular system.

Question 13

What is plasminogen converted into during fibrinolysis?

Answer 13

Plasminogen is converted into plasmin during fibrinolysis.

Question 14

What is the function of plasmin?

Answer 14

Plasmin degrades fibrin into soluble fibrin degradation products (FDPs).

Question 15

Name two physiological activators of plasminogen.

Answer 15

tPA (tissue plasminogen activator) and uPA (urokinase plasminogen activator) are physiological activators of plasminogen.

Question 16

How does streptokinase function in fibrinolysis?

Answer 16

Streptokinase forms a 1:1 complex with plasminogen, causing a conformational change that activates plasminogen to plasmin.

Question 17

What is the dosage protocol for streptokinase in myocardial infarction?

Answer 17

The dosage protocol for streptokinase in MI is 1.5 million units IV over 30–60 minutes.

Question 18

What enzyme directly converts plasminogen to plasmin?

Answer 18

Urokinase directly converts plasminogen to plasmin.

Question 19

Why is urokinase not immunogenic?

Answer 19

Urokinase is not immunogenic because it does not cause an immune response.

Question 20

What are the limitations of urokinase availability?

Answer 20

Urokinase has limited availability.

Question 21

How does rt-PA (alteplase) preferentially activate plasminogen?

Answer 21

Rt-PA (alteplase) preferentially activates plasminogen in the presence of fibrin, reducing systemic lytic states.

Question 22

What is the dosage protocol for rt-PA in acute myocardial infarction?

Answer 22

The dosage protocol for rt-PA in acute MI is 15 mg IV bolus, followed by 50 mg IV infusion over 30 minutes, then 35 mg over 60 minutes.

Question 23

What is the dose adjustment for rt-PA in patients weighing less than 65 kg?

Answer 23

The dose adjustment for rt-PA in patients under 65 kg is a reduced total dose.

Question 24

Name one contraindication for rt-PA use in elderly patients.

Answer 24

Rt-PA is contraindicated in elderly patients over 80 years old.

Question 25

What is the clinical significance of elevated plasma prothrombin?

Answer 25

Elevated plasma prothrombin is associated with an increased risk of thrombosis.

Question 26

What is the relevance of Factor V Leiden in thrombophilia?

Answer 26

Factor V Leiden causes resistance to activated protein C, increasing thrombotic risk.

Question 27

Which diagnostic test is recommended for recurrent thrombosis in family history?

Answer 27

Testing for thrombophilias is recommended for patients with recurrent thrombosis and a family history.

Question 28

How does Factor Xa inhibition contribute to anticoagulation?

Answer 28

Factor Xa inhibition prevents thrombin formation, contributing to anticoagulation.

Question 29

What are the advantages of Dabigatran over traditional anticoagulants?

Answer 29

Dabigatran offers predictable anticoagulant effects without the need for monitoring and fixed dosing.

Question 30

What are the fixed dosing schedules for Rivaroxaban?

Answer 30

Rivaroxaban’s fixed dosing schedule is 15 mg twice daily for 3 weeks, then 20 mg once daily for 3 months.

Question 31

What are the risks associated with thrombolytic therapy in hypotensive patients?

Answer 31

Thrombolytic therapy risks in hypotensive patients include severe bleeding and hemorrhagic complications.

Question 32

What is the significance of measuring plasma D-dimer in DVT diagnosis?

Answer 32

Measuring plasma D-dimer helps diagnose DVT by indicating fibrin degradation.

Question 33

What is the annual incidence rate of venous thromboembolism?

Answer 33

The annual incidence rate of venous thromboembolism is approximately 1 per 1000 people.

Question 34

How does age affect the incidence of venous thromboembolism?

Answer 34

The incidence of venous thromboembolism increases with age.

Question 35

What is the clinical presentation of a pulmonary embolism?

Answer 35

A pulmonary embolism presents clinically with sudden onset of shortness of breath, chest pain, and tachycardia.