Venous Thrombosis

Question 1

What are examples of arterial thrombotic events?

Answer 1

Coronary
Cerebral
Peripheral

Question 2

What are venous thrombotic events?

Answer 2

DVT
Pulmonary embolism

Question 3

Why does arterial thrombosis occur?

Answer 3

High pressure system
Atherosclerosis
Platelet rich thrombus

Question 4

How do we treat arterial thrombosis?

Answer 4

Aspirin and other anti-platelet drugs
Modify risk factors for atherosclerosis

Question 5

How does venous thrombosis occur?

Answer 5

Low pressure system
Platelets not activated
Activates coagulation cascade - rich in fibrin clot

Question 6

What is Virchow’s triad in venous thrombosis?

Answer 6

Blood stasis
Vessel wall damage
Hypercoagulability

Question 7

How can we treat venous thrombosis?

Answer 7

Heparin
Warfarin
New oral anticoagulants

Question 8

What are signs of DVT?

Answer 8

Hot, swollen, painful limb
Pitting oedema

Question 9

What are signs of pulmonary embolism?

Answer 9

Pulmonary infarction
Pleuritic chest pain
CV collapse / death
Hypoxia
Right heart strain

Question 10

What are risk factors for venous thromboembolism?

Answer 10

Age
Obesity
Pregnancy
Oestrogen therapy
Previous DVT or PE
Trauma / Surgery
Malignancy
Paralysis
Infection
Thrombophilia
Puerperium

Question 11

What factors make you more hyper coagulable?

Answer 11

Age
Pregnancy
Oestrogen therapy
Trauma / Surgery
Malignancy
Infection
Thrombophilia

Question 12

Age, pregnancy, oestrogen therapy, trauma / surgery, malignancy and infection are associated with what which can lead to hyper coagulability?

Answer 12

Associated with release of tissue factor, raised VWF and factor VIII

Question 13

What is thrombophilia?

Answer 13

Familial or acquired disorders of the haemostatic mechanism which are likely to predispose to thrombosis

Question 14

What are potential mechanisms of thrombophilia?

Answer 14

Increased coagulation activity (platelet plug formation; fibrin clot formation)

Decreased fibrinolytic activity
Decreased anticoagulation activity

Question 15

What are hereditary thrombophilias?

Answer 15

A group of genetic defects in which affected individuals have an increased tendency to develop premature, unusual and recurrent thromboses

Question 16

What are the main hereditary thrombophilias?

Answer 16

Factor V leiden
Prothrombin 20210 mutation
Antithrombin deficiency
Protein C deficiency
Protein S deficiency

Question 17

When do we consider thrombophilia screening?

Answer 17

Venous thrombosis <45 years old
Recurrent venus thrombosis
Unusual venous thrombosis
FH of venous thrombosis
FH of thrombophilia

Question 18

How do we manage hereditary thrombophilia?

Answer 18

Advice on avoiding risk
Short term prophylaxis - to prevent thrombotic events during periods of known risk
Short term anticoagulation - to treat thrombotic events
Long term anticoagulation - if recurrent thrombotic evens

Question 19

What history findings are important to assess risk of recurrent thrombosis?

Answer 19

Hx of previous thrombosis
Sponantenous thrombosis rather than acquired transient risk factor (e.g. immobility or surgery)
FH
Thrombophilia screen results

Question 20

What are causes of acquired thrombophilia?

Answer 20

Antiphospholipid antibody syndrome

Stronger risk factor for thrombosis than the hereditary thrombophilias

Question 21

What are features of antiphospholipid syndrome?

Answer 21

Recurrent thromboses - arterial (including TIAs), venous

Recurrent fetal loss
Mild thrombocytopenia

Question 22

What is the pathogenesis of antiphospholipid syndrome?

Answer 22

Antibodies lead to a conformational change in beta2 glycoprotein 1 (a protein with unknown function in health) which leads to activation of both primary and secondary haemostasis and vessel wall abnormalities

Question 23

What are antiphospholipid antibodies?

Answer 23

Autoantibodies which have specificity for anionic phospholipids and which prolong phospholipid dependent coagulation tests in vitro

Also known as lupus anticoagulants

Question 24

What are conditions associated with antiphospholipid antibodies?

Answer 24

Autoimmune disorders
Lymphoproliferative disorders
Viral infections
Drugs
Primary

Question 25

How do we treat antiphospholipid syndrome?

Answer 25

Activation of both primary and secondary haemostasis; arterial and Venus thrombosis

Thus we need to treat with both aspirin + warfarin