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Flashcards in Pulmonary Embolism Deck (24)
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1
Q

What are causes of PE?

A
VT in pelvis or legs - blot breaks off and pass through right side of heart and into pulmonary circulation
Septic emboli from right sided IE
Fat air or amniotic fluid embolus
Neoplastic embolus
RV thrombus post-MI
2
Q

What are risk factors for PE?

A
Recent surgery
Thrombophilia - antiphospholipid syndorme
Leg fracture
Prolonged bed rest
Malignancy
Pregnancy/post partum
COCP
Previous PE
3
Q

What are symptoms and signs of PE?

A

Symptoms:
Pleuritic chest pain, acute breathlessness, haemoptysis, dizziness, syncope, tachycardia, tachypnoea

Signs: Pyrexia, cyanosis, tachypnoea, tachycardia, crackles, hypotension, raised JVP, pleural rub, pleural effusion, Signs of DVT - red hot swollen leg

4
Q

What can be use to assess for PE risk?

A

Well’s score assesses clinical probability of PE

Clinical signs and symptoms of DVT (leg swelling and pain on palpation of deep veins) = 3
Alternative diagnosis is less likely than PE = 3
HR > 100 = 1.5
Immobilisation 3 days or surgery in last 4 weeks = 1.5
Previous DVT/PE = 1.5
Haemoptysis = 1
Malignancy receiving active treatment or in last 6 months = 1

PE likely > 4
PE unlikely if 4 or less

5
Q

Describe Well’s score

A

Clinical signs and symptoms of DVT (leg swelling and pain on palpation of deep veins) = 3
Alternative diagnosis is less likely than PE = 3
HR > 100 = 1.5
Immobilisation 3 days or surgery in last 4 weeks = 1.5
Previous DVT/PE = 1.5
Haemoptysis = 1
Malignancy receiving active treatment or in last 6 months = 1

PE likely > 4
PE unlikely if 4 or less

6
Q

What investigations if Well’s score > 4?

A

Immediate CTPA
If there is delay give LMWH

If pt has allergy to contrast or renal impairment, do VQ scan instead of CTPA

7
Q

What investigations if Well’s score 4 or less?

A

D-dimer test
If this is positive, immediate CTPA
If there is a delay, treat with LMWH

If pt has allergy to contrast or renal impairment, do VQ scan instead of CTPA

8
Q

What is a CTPA? Advantages over VQ scan?

A

CTPA is easier to perform
If negative, no further investigation or treatment
VQ may be used of pt is allergic to contrast or renal impairment

9
Q

What is the sensitivity and specificity of d-dimer? What does this mean?

A

High sensitivity - highly likely that it will detect patients who do have PE as having PE

Low specificity = low likeliness that it will identify patients who don’t have PE as not having PE –> actual negative correctly identified is low.

10
Q

What investigations in PE?

A

Bedside: SaO2, ECG
Bloods: FBC, U&E, Clotting, D-dimer
Imaging = CXR may show dilated pulmonary artery, CTPA, VQ

11
Q

What does the ECG show in PE?

A

Large S wave in lead I, large Q wave in lead III and inverted T wave in lead III
S1Q3T3

Tachycardia may be seen
RBBB - MARROW
Right axis deception

12
Q

What is the gold standard for PE diagnosis ? Why is this not used much?

A

Pulmonary angiography - significant complication rate

CTPA is used

13
Q

How is PE managed if haemodynamically stable?

A

LMWH or fondaparinux immediately
Unfractionated heparin if underlying renal impairment as LMWH has renal clearance
Treat for 5 days or until INR 2-3
Then start warfarin or DOAC
Overlap period for warfarin as warfarin also reduces Protein C and S anticoagulant factors resulting in hyper coagulable, prothrombotic state initially. Stop heparin when INR on warfarin is 2-3
Warfarin/DOAC should be continued for at least 3 months or beyond 3 months in unprovoked PE

14
Q

What type of heparin is normally used after PE diagnosis? When is this different?

A

LMWH or fondaparinus unless massive PE where thrombolysis, then unfractionated heparin

15
Q

How is PE managed if haemodynamically unstable - circulatory failure/hypotension?

A

Thombolyse - first line treatment

16
Q

When can LWMH be stopped?

A

LMWH can be stopped when INR is 2-3 on warfarin

17
Q

How long should patient be anti coagulated?

A

At least 3 months then reassess risk to benefit profile. IF unprovoked, over 3 months

18
Q

What anticoagulation in malignancy?

A

LMWH or fondaparinux for 6 months

19
Q

What management in pregnancy?

A

LMWH until delivery/end of pregnancy

20
Q

What if there is a contra-indication to anticoagulation?

A

Fit vena cava filter

21
Q

What is unprovoked PE? What is management for Unprovoked PE?

A

PE in patients with no known provoking risk factors - consider investigation for underlying malignancy.
Thombophilia screen

Manage with anticoagulation for > 3 months

22
Q

What are preventative strategies for PE?

A

Heparin to all immobilised patients

Stop HRT/COCP pre-op

23
Q

What is the mechanism of action of heparin? SE? CI? Antidote?

A

Enhances antithrombin III action
This inactivates thrombin, factor Xa and other proteases preventing formation of fibrin clot

SE: heparin induced thrombocytopenia - immune response to platelets
Haemorrhage
Elevation of aminotransferases - not associated with liver dysfunction
Hyperkalaemia

Contraindicated with risk of bleeding:
Uncontrolled BP, liver disease, stroke
Severe liver disease, severe hypertension

Protamine sulphate

24
Q

What is the MOA/SE/CI/Antidote to warfarin?

A

Inhibits enzymes that activate vitamin K
Vitamin K is essential for formation and activation of clotting factors 1972(2,7,9,10)
Thus acts as vitamin K antagonist.
Clotting factors are not made negative to attract them to Ca at epithelial damage - reduced clotting.
Also initially affects protein C and S natural anticoagulant factors so initially prothrombotic state - heparin cover required.

SE: bleeding - careful with anti platelets and NSAIDs
Osteoporosis

CI: pregnancy -> teratogen crosses placenta, use heparin

Overdose: INR high
Prothrombin complex concentrate, Fresh frozen plasma
Vitamin K IV