Pulmonary Embolism Flashcards by Ethan Thrower

What is pulmonary embolism?

Blockage in a pulmonary artery caused by a thrombus dislodging and travelling to the pulmonary arteries.

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Where does deep vein thrombosis occur?

Deep veins of the leg / pelvis

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What does a venous thromboembolism refer to?

Both DVT and PE.

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Most commonly where does a deep vein thrombosis form?

Calf

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How do you find VTE in the circulation?

Radioactive fibrinogen

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Why is the epidemiology of VTE difficult?

It’s hard to define what is a clot e.g two platelets stuck together.
> Common and frequently missed.

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Virchow’s triad

Local trauma to the vessel wall
Hypercoagubility
Stasis of blood flow

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What are indications of a deep vein thrombosis?

DVT in the lower legs presents with:
Unilateral calf swelling
Erythema
Leg warmth

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Erythema

Redness of the skin / mucous membranes.

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How can you detect a venous thromboembolism?

Detect with ultrasound

Venography

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What are the symptoms of pulmonary embolus?

Dyspnea
Pleuritic pain
Cough
Leg swelling
Leg pain
Hemoptysis
Palpitations
Wheezing
Angina

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What is important to think about when looking at symptoms?

Symptoms are non-specific so you need to take into account risk factors of your patient e.g having a prostate surgery a week ago.

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What are the risk factors of VTE?

Obesity
Malignancy 
Increased oestrogen (oestrogen contraceptive pill)
Pregnancy
Age
Prolonged bed rest
Surgery longer than 30 minutes
Orthopaedic surgery
Journeys longer than 4 hours

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How does a large pulmonary embolus present?

Collapse due to cardiac arrest
Present with systemic hypotension
Right heart failure

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How do segmental pulmonary emboli present?

Breathlessness

Angina

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What causes death with pulmonary embolisms?

Progressive right heart failure is the usual immediate cause of death from PE.

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In a pulmonary embolism how do you know if the right ventricle is failing?

Clinically elevated JVP
ECG - right axis deviation, right bundle branch block.
Elevated troponin
Cardiac muscle damage
Elevated BNP
CT Pulmonary angiogram

BNP

Brain natriuretic peptide (BNP) test is a blood test that measures levels of a protein called BPN that is made by your heart and blood vessels. BNP levels are higher than normal when you have heart failure.

If the right ventricle is failing what 3 things would you see on a CT pulmonary angiogram.

Pulmonary artery width is greater than the aorta
RV pushing into LV
Contrast backing into IVC

How do smaller pulmonary embolisms present?

No or little right ventricle dysfunction.
Impaired gas exchange - breathlessness
Poorly perfused alveoli (may have hypoxaemia)
Alveolar hyperventilation
Pulmonary infarct

Pleuritic pain
Haemoptysis
Cough

Haemoptysis

Hemoptysis is the coughing up of blood or blood-stained mucus from the bronchi, larynx, trachea, or lungs.

What can cause a nonthrombotic pulmonary embolism?

Fat embolism
Amniotic fluid embolism
Intravenous drug use

What can cause a fat embolism?

Breaking a long bone - release fat from the bone marrow.

What are the diagnostic investigations advised by NICE?

In patients presenting with signs or symptoms of PE, carry out the
following to exclude other causes:
• an assessment of their general medical history
• a physical examination
• a chest X-ray

If PE suspected use the two-level PE Wells score.

When should you do a D-dimer test?

When you do not think the patient has a PE to exclude it.

CTPA

CT pulmonary angiogram

What does the D-dimer test test for?

Troponin levels

How are troponin levels affected in PE?

Increased troponin levels in PE and right ventricular failure.

Outline the D-dimer test.

D-dimer is elevated in more than 90% of patients with a PE. Relfects the break down of plasmin and endogenous thrombolysis. Not specific: Can also be elevated in MI, sepsis / most systemic illnesses. Negative predictive value. Low wells plus a normal D-dimer means VTE is excluded.

Who would you want to avoid doing a CTPA on?

Pregnant women and women that are breastfeeding.

In pregnant / breastfeeding women what test would you do in place of a CTPA for suspected PE?

High probability V/Q scan | Venous ultrasonography

High probability V/Q scan

Uses inhalation of a radioactive isotope to image ventilation of the lungs. A high probability lung scan indicated a high likelihood of emboli, particularly in patients with a high pretest probability. The cardinal sign of pulmonary embolism is an underperfused part of the lungs on perfusion scanning.

Venous ultrasonography

Venous ultrasound uses sound waves to produce images of the veins in the body. It is commonly used to search for blood clots, especially in the veins of the leg (DVT).

What is the treatment for a pulmonary embolism?

ABC (airway, breathing, circulation) - o2, fluids, inotropes. Offer low molecular weight heparin Continue anticoagulation with warfarin, NOAC or LMWH.

What patients would you not offer low molecular weight heparin to?

Patients with severe renal impairment Increased risk of bleeding Haemodynamically unstable patients.

What do warfarin, NOAC, and LMWH do?

Prevents additional thrombus formation and permits endogenous fibrinolytic mechanisms to lyse clot that has already been formed. Note: Does NOT directly dissolve thrombus that already exists).

Thrombolysis

Thrombolysis, also known as thrombolytic therapy, is a treatment to dissolve dangerous clots in blood vessels, improve blood flow, and prevent damage to tissues and organs.

When is thrombolysis used?

Haemodynamically compromised patients. | Pulmonary hypertension or patients with right ventricular dysfunction.

When is embolectomy used?

Reserved for patients at a high risk of death.

What investigations do you follow up with for patients that had a VTE?

Investigations for cancer. > CT of abdomen > mammogram in women.

When is thrombophilia testing used?

Used for patients that experienced an unprovoked PE or if it is planned to stop anticoagulation treatment for people that had a PE.

How can a DVT cause a stroke bypassing the lungs?

Patent foramen ovale.