Resp V

Question 2

Name and state the drug classes used to treat idiopathic pulmonary hypertension [4]

Answer 2

Idiopathic pulmonary hypertension may be treated with:

Calcium channel blockers
Intravenous prostaglandins e.g., epoprostenol
Endothelin receptor antagonists e.g., macitentan
Phosphodiesterase-5 inhibitors e.g., sildenafil

Question 3

Which inherited disorders increase the risk of PE? [5]

Answer 3

Factor V Leiden mutation:
- Normally used for blood clotting: helps enzyme reaction to form fibrin in blood clot
- Once the coagulation process is turned on in people with factor V Leiden, it turns off more slowly than in people with normal factor V

Antithrombin deficiency
- Normally anti-thrombin acts as the inhibitory component to thrombin formation

Prothrombin deficiency

Protein C & S deficiencies

Antiphospholiipid syndrome

Question 4

Which type of hormone therapy increases the risk of PE? [1]

Answer 4

Hormone therapy with oestrogen (e.g., combined oral contraceptive pill or hormone replacement therapy)

Question 5

Explain what is meant by the PERC rule

Answer 5

The pulmonary embolism rule-out criteria (PERC) are recommended by the NICE guidelines (2020) when the clinician estimates less than a 15% probability of a pulmonary embolism to decide whether further investigations for a PE are needed. If all the criteria are met, further investigations for a PE are not required.

Question 6

What ABG results would indicate PE? [1]

Explain your answer [1]

Answer 6

TOM TIP: Patients with a pulmonary embolism often have respiratory alkalosis on an ABG.

Hypoxia causes a raised respiratory rate.

Breathing fast means they “blow off” extra CO2.

A low CO2 means the blood becomes alkalotic.

Question 7

A V/Q scan is of limited use in patients with which co-morbidities? [3]

Answer 7

A V/Q scan is of limited use in patients with:
* significant underlying lung disease
* left ventricular failure
* congestive cardiac failure

Question 8

Describe the treatment algorithm for patients who have PE confirmed and are haemodynamically unstable [4]

Answer 8

First line:
- heparin: 10,000 units intravenously as a loading dose initially, followed by 18 units/kg/hour intravenous infusion

PLUS: thrombolysis: (involves injecting a fibrinolytic (breaks down fibrin) medication that rapidly dissolves clot)
- Alteplase or
- Streptokinase or
- Urokinase

PLUS:
- anticoagulation with unfractionated heparin (UFH) for several hours after the end of thrombolysis before: switching to apixaban or rivaroxaban; low molecular weight heparin (LMWH) is an alternative if these are unsuitable - this is preferable

CONSIDER: vasoactive drug if SBP < 90 mmHG after thrombolysis
- noradrenaline or
- dobutamine

-

Question 9

Describe the treatment algorithm for patients who have PE confirmed and are haemodynamically stable [4]

Answer 9

First line: anticoagulation:
- apixaban or
- rivaroxaban

instead of using low-molecular weight heparin (LMWH) until the diagnosis is confirmed, NICE now advocate using a DOAC once a diagnosis is suspected, with this continued if the diagnosis is confirmed
- if neither apixaban or rivaroxaban are suitable then either LMWH followed by dabigatran or edoxaban OR LMWH followed by a vitamin K antagonist (VKA, i.e. warfarin)

Stable, no renal impairment or co-morbidities: offer apixaban/rivaroxaban. If not-suitable, LWMH for 5 days then offer edoxaban/warfarin*

Question 10

Describe the long term managment of PE for:

• most people [4]
• patients suffering from antiphospholipid syndrome [1]
• pregnant people [1]

Answer 10

DOACs: most people
- apixaban
- rivaroxaban
- edoxaban
- dabigatran

Warfarin: for antiphospholipid syndrome patients

LMWH for pregnant people

Question 11

Describe how massive PE causes hemodyanmic collapse [7]

Answer 11

Question 12

Describe how PE can cause cardiogenic shock [2]

Answer 12

Cardiogenic shock
- Severe PE may lead to decreased cardiac output, causing systemic hypotension, impaired end-organ perfusion, and ultimately cardiogenic shock.

Question 13

Which arrythmias can PE lead to [3]

Answer 13

Arrhythmias: PE can provoke supraventricular and ventricular arrhythmias, such as:
- atrial fibrillation
- ventricular tachycardia
- ventricular fibrillation

which can further compromise hemodynamics.

Question 14

Describe three subacute complications of PE

Answer 14

Infarction and lung necrosis
- PE can cause ischemic injury to the lung parenchyma, leading to pulmonary infarction, haemorrhage, or lung necrosis.

Pleural effusion:
- Inflammatory processes triggered by PE may cause pleural effusion, which may be exudative or hemorrhagic.

Pneumothorax:
- Rarely, PE-induced lung infarction may lead to pneumothorax due to the rupture of a bulla or necrotic lung tissue

Question 15

Describe a chronic complication of PE [1]

Answer 15

Chronic thromboembolic pulmonary hypertension (CTEPH):

• CTEPH is a rare but serious complication characterized by unresolved thrombotic occlusions in the pulmonary arterial system, turning into fibrotic tissue leading to increased pulmonary vascular resistance, pulmonary hypertension, and eventually right heart failure.

Question 16

What is the most appropriate next step in the investigation of suspected pulmonary embolism if D-dimer negative?

Answer 16

Stop anticoagulation and consider an alternative diagnosis

Question 17

What is the most appropriate next step in the investigation of suspected pulmonary embolism if medium-high (> 15%) pre-test probability of PE? [1]

Answer 17

A 2-level PE Wells score should be performed:

Clinical probability simplified scores
PE likely - more than 4 points
PE unlikely - 4 points or less

Question 18

What is the most appropriate next step in the investigation of suspected pulmonary embolism if CTPA negative? [1]

Answer 18

Consider the possibility of DVT and arrange proximal leg vein ultrasound if suspected

Question 19

PE would cause change to axis deviation? [1]

Answer 19

Right axis deviation

Question 20

State 4 invasive procedures used to treat PE if needed

Answer 20

• Embolectomy
• Mechanical fragmentation with R heart angiography
• Pulmonary thombro-endarterectomy
• IVC filter

Question 21

Which of the following is used to treat chronic PEs unresolved after 3 months

• Embolectomy
• Mechanical fragmentation with R heart angiography
• Pulmonary thombro-endarterectomy
• IVC filter

Answer 21

Pulmonary thombro-endarterectomy (PTE)

Question 22

Name a risk [1] and benefits [2] of using unfractionated heparin in treating PE [4]

Answer 22

Risks:
- Heparin induced thrombocytopenia (HIT)

Benefits:
- Rapid reversal possible
- More rapid anticoagulation

Question 23

Describe the different bridging times for LMWH if using:
- Warfarin
- Dabigatran or edoxaban
- Rivaroxaban or apixaban

Answer 23

Warfarin:
- Start LMWH and initiate warfarin at same time then after 5-10 days change to just warfarin

Dabigatran or edoxaban
- 5 days of LMWH with both then switch to doac same day

Rivaroxaban or apixaban
- No bridge - only use them

Question 24

Answer 24

a prolonged PR interval

Question 25

Answer 25

**Hepatotoxicity**

Question 26

Answer 26

**Optic neuritis**

Question 27

Answer 27

**Gout**

Question 28

Answer 28

**Type IV**

Question 29

Describe the diagnostic pathway for PEs

Answer 29