Deep Vein Thrombosis and Pulmonary Thromboembolism Flashcards Preview

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Flashcards in Deep Vein Thrombosis and Pulmonary Thromboembolism Deck (23)
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1

What is the incidence of DVT?

1 in 1000 per annum

2

What is the case fatality rate of venous thromboembolism?

1-5%

3

What is the incidence of PE?

3000-5000 per annum

4

What percentage of autopsies reveal a PE?

20% of autopsies

5

What are the components of Virchow's Triad?

Stasis
Vessel damage
Hypercoagulability

6

What are examples of presentations of venous thromboembolism?

Limb DVT
Pulmonary embolism
Visceral venous thrombosis
Intracranial venous thrombosis
Superficial thrombophlebitis

7

What are the features of venous thrombus?

Red thrombus - fibrin and red cells
Results in back pressure
Principally due to stasis and hypercoagulability

8

What are the features of arterial thrombus?

White clot - platelets and fibrin
Results in ischaemia and infarction
Principally secondary to atherosclerosis

9

What is the presentation of DVT?

Unilateral limb swelling
Persisting discomfort
Calf tenderness
Warmth
Erythema
May also be clinically silent

10

What are the potential long-term consequences of DVT?

Post-phlebitic syndromes
e.g. swelling, discomfort, pigmentation, ulceration

11

What is the presentation of PE?

Pleuritic chest pain
Dyspnoea
Haemoptysis
Tachycardia
Pleural rub on auscultation

12

What is the presentation of massive PE?

Severe dyspnoea of sudden onset
Collapse
Central cyanosis
Tachycardia
Hypotension
Raised JVP
Altered heart sounds
May cause sudden death

13

What are the potential long-term consequences of PE?

Most recover fully
May result in pulmonary hypertension

14

What are the risk factors for venous thromboembolism?

Increasing age
Tissue trauma
Immobility
Obesity
Smoking
Systemic disease e.g. cancer
Genetics e.g. heritable thrombophilia
Pregnancy
Exogenous oestrogen e.g. OCP, HRT

15

What is the most prevalent heritable thrombophilia?

Factor V Leiden

16

What is the link between VTE and travel?

Relative risk increased by 2-3
Increased risk in short, tall or overweight people, and in women on the OCP

17

How is DVT diagnosed?

Clinical assessment
D-dimer
Compression ultrasound

18

How is a d-dimer test useful?

Negative result is more useful as it will rule out DVT
Positive result will not confirm DVT but will indicate need for more investigation

19

How is PE diagnosed?

Clinical assessment
D-dimer in unlikely patients
Isotope ventilation/perfusion scan
CT pulmonary angiogram

20

How can VTE be prevented in hospital?

Early mobilisation
Anti-embolism stockings
Daily injections of low molecular weight heparin

21

What pressures are provided by anti-embolism stockings?

18mmHg at the ankle
14mmHg at the mid-calf
8mmHg at the upper thigh

Result in maximal femoral blood flow velocity of 139% of the baseline

22

When are graduated compression stockings useful?

Prevention of DVT
Chronic venous insufficiency
Varicose veins
Oedema
Lymphoedema
Prevention of post-phlebitic syndrome

23

What is the treatment of VTE?

Low molecular weight heparin for 5 or more days then oral anticoagulant (warfarin) for at least 3 months
Thrombolysis for massive PE
Vena caval filter