Venous Thromboembolism

Question 1

Thrombosis

Answer 1

Pathological formation of a blood clot within a vessel

Question 2

Embolism

Answer 2

Rupture of clot from vessel wall

Travels through circulation until obstructed by smaller vessel

Question 3

Venous thrombi

Answer 3

Red clots

RBCs within a fibrin mesh

Question 4

Arterial thrombi

Answer 4

White clots

Platelets and fibrin

Question 5

Majority of DVT originate in

Answer 5

Calf venous sinuses

Question 6

Pulmonary embolism

Answer 6

3rd most common cause of CV death

Question 7

Virchow’s Triad- VTE cause

Answer 7

Reduced blood flow (stasis)
Vessel wall disorder
Hypercoagulability

Question 8

VTE epidemiology

Answer 8

Hereditary 25%
Acquired 50%
Idiopathic 40%
Caused by antithrombin, protein C + S deficiency

Question 9

Strong Risk Factors VTE

Answer 9

Fracture hip
Major trauma
Hip/knee replacement
Spinal cord injury
Major surgery
Hospitalisation with acute medical illness

Question 10

Moderate Risk Factors VTE

Answer 10

Previous VTE
Cancer
Resp. Failure
Thrombophilia
Pregnancy
Combined pill/HRT

Question 11

Weak Risk Factors VTE

Answer 11

Bed rest > 3 days
Travel
Obesity
Varicose veins
Day-case surgery

Question 12

DVT Presentation

Answer 12

Unilateral

Pain, swelling, tenderness

Question 13

Objective diagnosis DVT

Answer 13

Clinical pre-test probability- Well’s score
D-dimer
Radiological assessment

Question 14

Well’s score DVT

Answer 14

Active cancer within last 6 months
Recent immobilisation
Recently bedridden
Localised tenderness near deep veins
Entire leg swollen
Pitting oedema

Question 15

D-dimer DVT

Answer 15

Blood test

Tests for non-specific marker of fibrin formation

Question 16

Radiological assessment DVT

Answer 16

Usually compression ultrasound
Sometimes venography
CT scan

Question 17

DVT Complications

Answer 17

Pulmonary embolism
Recurrent VTE
Post-thrombotic syndrome

Question 18

Post-thrombotic syndrome

Answer 18

Recurrent pain + swelling in leg due to venous hypertension
Due to obstruction + valve damage
30-50% of proximal DVT

Question 19

Pulmonary Embolism presentation

Answer 19

Pulmonary infarction
Breathlessness
Collapse, shock

Question 20

PE signs + symptoms

Answer 20

Breathlessness
Collapse
Tachycardia
Crepitations 
Raised JVP 
Pleural effusion

Question 21

PE Diagnosis

Answer 21

Non-diagnostic –> may or may not be present

Question 22

PE Arterial gases

Answer 22

Hypoxia
Low CO2
often normal

Question 23

Hampton’s Hump

Answer 23

Peripheral wedge shaped opacity representing pulmonary infarction + atelectasis secondary to a pulmonary embolus

Question 24

PE Diagnostic tests

Answer 24

CT Pulmonary Angiogram
Isotope Lung
Echocardiogram
Pulmonary angiogram
D-dimer
Leg ultrasound

Question 25

DVT, VTE + PE treatment

Answer 25

Start heparin if likely Once confirmed, continue heparin with warfarin Stop heparin after minimum 5 days (INR in normal range for 2 days) Continue warfarin

Question 26

Low molecular weight heparin

Answer 26

``` Mainly VTE treatment Safer than unfractioned Half life 4 hours Anti-Xa Anti-thrombin Subcutaenous ```

Question 27

Un-fractioned Heparin

Answer 27

90 min half life Used when rapid reversibility required IV or subcutaenous

Question 28

Heparin side effects

Answer 28

Major bleeding Heparin induced thrombocytopenia- low platelets Osteoporosis

Question 29

Specific heparin antagonist

Answer 29

Protamine sulphate

Question 30

Fondaparinux

Answer 30

18 hours half life Synthetic pentasaccharide Unsuitable if renal impairment

Question 31

Warfarin

Answer 31

``` Vitamin K antagonist Oral 36 hour hald life Primarily affects INR Teratogenous Major bleeding risk Reduces risk of recurrence during treatment by 90% ```

Question 32

DOACs

Answer 32

Dabigatran | Rivaroxaban

Question 33

Dabigatran

Answer 33

DOA | Acts on thrombin

Question 34

Rivaroxaban

Answer 34

DOA | Acts on factor Xa

Question 35

Pregnancy VTE

Answer 35

Use LMWH

Question 36

Breast feeding VTE

Answer 36

LMWH and warfarin safe | NOT DOACS

Question 37

Cancer VTE

Answer 37

LMWH

Question 38

VTE recurrence

Answer 38

Risk after stopping anticoagulants 5% risk year 1 30% risk by 10 years

Question 39

Thrombolysis

Answer 39

"clot-busting" therapy | Massive PE or life threatening DVT

Question 40

Inferior vena cava filter

Answer 40

If major contra-indication to anticoagulation

Question 41

Thrombophilia

Answer 41

laboratory detected predisposition to thrombosis

Question 42

Thrombophilia heritable causes

Answer 42

``` Factor V Leiden Prothrombin gene mutation Protein C deficiency Protein S deficiency Antithrombin deficiency ```

Question 43

Antiphospholipid Syndrome (APS)

Answer 43

Acquired form thrombophilia Primary Secondary to connective tissue disorder e.g. SLE

Question 44

APS Diagnostic criteria

Answer 44

Thrombosis Pregnancy morbidity Lab criteria