Pulmonary Embolism

Question 1

What is a pulmonary embolism?

Answer 1

An embolism becoming lodged in a pulmonary artery

Question 2

Through what vessels does blood return to the heart?

Answer 2

Superior and inferior vena cava into the right atrium

Question 3

What mechanisms allow blood in deep veins to return to the heart?

Answer 3

Skeletal muscle contraction and valves

Question 4

Where does the emboli usually originate from?

Answer 4

Deep vein thrombosis

Question 5

How does an emboli form? (6)

Answer 5

Endothelial damage
Local vasoconstriction
Platelet plug formation
Coagulation cascade
Fibrin Reinforcement
Clot grows and may naturally  break down (D-dimers formed) or clot breaks free forming thromboembolus.

Question 6

What is a ventilation perfusion mismatch and how does it occur in PE?

Answer 6

When there is one of either adequate ventilation or perfusion to the alveoli but not both.

There is adequate ventilation of air but no perfusion due to the ischaemia.

The larger the V/Q mismatch the worse.

Question 7

How does a respiratory alkalosis occur in PE?

Answer 7

Due to V/Q mismatch hyperventilation occurs, this means excessive CO2 is released and an alkalosis occurs

Question 8

If someone has a PE, what congenital abnormality should be checked for?

Answer 8

Atrial septal defect

They can go on to have an embolic stroke as can pass into left atrium

Question 9

What are the components of Virchow’s triad?

Answer 9

1. Stasis (slow blood flow e.g. can be caused by skeletal muscle inactivity)
2. Hypercoagulation (genetic or acquired reasons - surgery of COCP)
3. Damage to endothelium (infections, chronic inflammation, smoking)

Question 10

What are the symptoms of PE?

Answer 10

Chest Pain
SOB
Fatigue
Swollen and erythmatous calf
Dyspnoea
Crackles
Tachycardia
Tachypnea
Fever
Hemoptysis
Sudden Death (if in pulmonary saddle)

Question 11

What is the sequale of multiple PEs happening over time?

Answer 11

Pulmonary hypertension

Right ventricular failure

Question 12

How is a PE diagnosed?

Answer 12

CT Pulmonary Angiogram
Ventilation Perfusion Scan
D-dimer blood test

Question 13

What is the treatment of a PE?

Answer 13

Thrombolysis - IV alteplase

Pulmonary Thrombectomy

Question 14

What is the long-term management to prevent future PE?

Answer 14

Anticoagulation medication:
Warfarin
Heparin

Compression stockings
Lifestyle changes

Question 15

What is the typical triad of symptoms a fat emboli?

Answer 15

Hypoxemia
Neurologic abnormalities
Petechial rash

Question 16

What are risk factors of fat emboli?

Answer 16

Long bone fractures

Liposuction

Question 17

What is an amniotic fluid embolism?

Answer 17

A type of pulmonary embolism that can occur in pregnant women leading to disseminated intravascular coagulation

Question 18

What are risk factors for PE?

Answer 18

Obesity
Malignancy
Immobilization
COCP 
Cancer (due to hypercoagulability)

Question 19

What changes are seen on an electrocardiogram in PE?

Answer 19

Prominent S-wave in lead I
Q-wave in lead III
Inverted T wave in lead III

SQT-133

If severe right bundle branch block and right axis deviation

Question 20

What signs may be seen on a chest x-ray in PE?

Answer 20

Westermark sign

Hampton hump

Question 21

What signs may be seen on a echocardiogram in PE?

Answer 21

McConnell Sign

Question 22

When might a CTPA with contrast be avoided in a patient with suspected PE? What might be used instead?

Answer 22

CTPA with contrast should be avoided in patients with chronic renal failure

A VQ lung scan is a good alternative

Question 23

What are the components of the Wells Score?

Answer 23

Clinical signs and symptoms of DVT: +3
PE is #1 diagnosis or equally likely:+3
Heart rate >100: +1.5
Immobilisation at least 3 days or surgery in the previous 4 weeks: +1.5
Previous, objectively diagnosed PE or DVT: +1.5
Haemoptysis: +1
Malignancy w/treatment within 6 months or palliative: +1

Question 24

What do the levels of Wells score correspond to?

Answer 24

0-1 low risk group
2-6 Moderate risk group
>6-12.5 High risk group

If > 4 points likely: Immediate CTPA, if delay get interim therapultic anticoagulation: DOAC: apixaban or rivaroxaban

If < 4 points unlikely: D dimer test, if positive CTPA, if negative consider alternative diagnosis.

Question 25

What are the contraindications for thrombolytic treatment?

Answer 25

Intracranial hemorrhage, 
stroke or head trauma within the past 3 months, Blood pressures >185 mm Hg systolic or >110 mm Hg
diastolic
Active bleeding, or known 
arteriovenous malformation

Question 26

What are good interim anticoagulation mediations?

Answer 26

DOACs

Apixaban or Rivaroxaban

Question 27

When are DOACs used in place of LMWH?

Answer 27

DOACs first-line for most people (2020)

DOACs in patients with active cancer

Question 28

Is cancer screening now routine following VTE diangosis?

Answer 28

Not since 2020

Question 29

What are the first line anticoagulant recommendations?

What are the alternatives?

Answer 29

Apixaban or Rivaroxaban
if not suitable
LMWH followed by dabigatran or edoxaban or LMWH followed by a vitamin K antagoist (i.e. warfarin)

(Still LMWH + warfarin in severe renal impairment or in antiphospholipid syndrome)

Question 30

What is the recommended length of anti-coagulation therapy?

Answer 30

At least 3 months
Then depends on if provoked or unprovoked
If provoked stop at 3 months
If unprovoked 6 months in total