Pulmonary Embolism Flashcards

1
Q

How does thrombosis differ from haemostasis?

A

thrombosis occurs within the vessel while physiological haemostasis occurs outside the vessel wall as a result of injury

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2
Q

What are the the factors that influence thrombosis according to Virchow’s triad?

A

1) changes in blood flow (stasis or turbulence)
2) vessel wall dysfunction
3) changes in blood components, leading to hypercoagulability

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3
Q

Are venous thrombi red or white?

A

Red - rich in red blood cells and fibrin

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4
Q

Are arterial clots red or white?

A

White - rich in platelets

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5
Q

What is the most common cause of PE?

A

DVT

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6
Q

Other than a DVT, give 3 other sites where thrombi can originate to cause a PE:

A

1) upper limb
2) cerebral venous sinuses
3) splanchnic veins (hepatic, portal and mesenteric)

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7
Q

Give 12 risk factors for venous thromboembolisms:

A

1) surgery
2) coagulation disorders
3) immobilisation (bed rest >3 days)
4) age
5) trauma
6) recent long haul travel
7) acute medical admission
8) obesity
9) pregnancy
10) ethnicity
11) combined oral contraceptive/ HRT
12) cancer

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8
Q

Give 7 clinical presentations associated with pulmonary embolism:

A

1) pleuritic chest pain
2) breathlessness
3) haemoptysis
4) tachypnoea
5) tachycardia
6) crackles and pleural rub on auscultation
7) syncope

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9
Q

What is the nature of the chest pain experienced in a PE?

A

pleuritic

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10
Q

What auscultation findings support diagnosis of a PE? (2)

A
  1. Crackles
  2. Pleural rub
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11
Q

Give two examination findings that support diagnosis of a pulmonary embolism:

A
  1. Raised JVP
  2. Right ventricular heave (seen in severe cases)
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12
Q

What is the gold standard investigate for PE?

A

CT pulmonary angiogram

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13
Q

Describe ECG findings that would support a diagnosis of PE:

A

right ventricular strain pattern: T wave inversion in the inferior and right precordal leads

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14
Q

Give 4 initial investigations that may be used to assess breathlessness associated with a PE:

A

1) ECG
2) CXR
3) ABG
4) Biomarkers of cardiac injury such as BNP and troponin

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15
Q

What is the name of the risk calculator scoring system for PE?

A

Well’s Score

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16
Q

A score over how many points makes a PE ‘likely’ according to the Wells score?

A

> 4

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17
Q

Summarise the Wells Score criteria for pulmonary embolism risk:

A

1) signs and symptoms of DVT - 3 points
2) alternative diagnosis less likely than PE - 3 points
3) HR > 100 bpm - 1.5 points
4) immobilisation (>3 days) or surgery - 1.5 points
5) previous DVT/PE - 1.5 points
6) haemoptysis - 1 point
7) malignancy - 1 point

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18
Q

What investigation is used for patients deemed to be “PE unlikely” according to the Wells score?

A

D-dimer

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19
Q

Give 5 instances other than VTE where D-dimer may be raised:

A

1) advanced age
2) infection
3) inflammation
4) cancer
5) pregnancy

20
Q

True or false: if Wells score verdict is “PE unlikely” but D-dimer is raised, you should still ensure the patient has a CT scan

A

true

21
Q

Give an alternative to CTPA for investigation of PEs:

A

ventilation-perfusion isotope lung scanning

22
Q

Describe the two phases of ventilation-perfusion isotope lung scanning:

A

1) perfusion phase - radio-labelled albumin is injected IV and used to access blood flow to the lung
2) ventilation phase - patients inhale radio labelled xenon to access air delivery to the lungs

23
Q

Fill in the gap: diagnostic testing for suspected PE should be performed urgently and completed within __ hrs of the initial presentation

A

24

24
Q

What is the initial treatment for PEs?

A

parenteral anticoagulants (Oral liquid)

25
Q

Give two examples of anticoagulants that can be given parenterally:

A

1) LMWH
2) fondapurinux

26
Q

Name the four types of DOAC:

A

1) apixaban
2) edoxaban
3) rivaroxaban
4) dabigitran

27
Q

What does dabigitran inhibit?

A

thrombin

28
Q

What clotting factor does apixaban, edoxaban and rivaroxaban inhibit?

A

Factor Xa

29
Q

Which two DOACs are given AFTER (5 days) parenteral anticoagulants following a PE?

A

1) endoxaban
2) dabigitran

30
Q

Which two can be used as an alterative to parenteral anticoagulation from the onset of a PE?

A

1) apixaban
2) rivaroxaban

31
Q

What two anticoagulants should not be used in pregnant women?

A

1) warfarin
2) DOACs
(they can cross the placenta)

32
Q

True or false: warfarin and LMWH are safe for breast feeding women

A

true

33
Q

What anticoagulant should be avoided in breast feeding women?

A

DOACs

34
Q

What anticoagulant is most effective in treating thrombosis in cancer patients?

A

LMWH (more so than warfarin)

35
Q

True or false: thrombolysis therapy is not used in the treatment of PE or DVT unless the VTE is massive and likely to kill the patient

A

true

36
Q

Give two surgical interventions for the management of PEs:

A

1) surgical embolectomy
2) inferior vena cava filters

37
Q

How long should anticoagulation last after a PE at minimum?

A

3 months (then patient should be reviewed to decide on further anticoagulation)

38
Q

What is post-thrombotic syndrome?

A

a complication of acute deep vein thrombosis, characterized by chronic pain, swelling and skin changes in the affected limb following the thrombotic episode

39
Q

How can the risk of post-thrombotic syndrome be reduced?

A

Compression stockings

40
Q

What is factor V leiden?

A

a mutation in clotting factor V that causes factor Va to be resistant to inactivation by activating protein C, leading to increased thrombin generation

41
Q

Name 4 thrombophilia disorders?

A
  1. Factor V leiden
  2. Reduced antithrombin
  3. Reduced protein C and protein S
  4. Antiphospholipid syndrome
42
Q

Describe how reduced/ dysfunctional antithrombin can increase thrombin risk:

A

antithrombin functions as an anticoagulant by inhibiting thrombin and factor Xa and without it, thrombin generation is increased

43
Q

Describe how reduced/ dysfunctional protein C and protein S can increase thrombin risk:

A

protein C and protein S inhibit the clotting system and without them, thrombin generation increases

44
Q

What vitamin are protein C and protein S dependent on?

A

vitamin K

45
Q

What is antiphospholipid syndrome?

A

condition associated with autoantibodies directed against protein-binding phospholipids that results in increased coagulation activity
(may be the underlying cause of recurrent VTE episodes and VTE in younger patients)