Pulmonary embolism Flashcards by Clarissa Rowe

Define pulmonary embolism

Occlusion of pulmonary vessels, most commonly by a thrombus that has travelled to the pulmonary vascular system from another site

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Aetiology of pulmonary embolism

Thrombus
95% arise from DVT in lower limbs
Rarely arises in right atrium (in AF patients)

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Other causes of thrombus

Amniotic fluid
Air
Fat
Tumour
Mycotic

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Risk factors for pulmonary embolism

Surgical patients
Immobility
Obesity
OCP
Heart failure
Malignancy

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Epidemiology of pulmonary embolism

prevalence + DVT

Relatively COMMON

Occur in 10-20% patients w/ confirmed proximal DVT

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Presenting symptoms of pulmonary embolism

general + 4types of PE

Depends on SITE & SIZE of embolus

Small
Moderate
Large
Multiple small recurrent

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Presenting symptoms of pulmonary embolism - small

May be ASYMPTOMATIC

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Presenting symptoms of pulmonary embolism - moderate

Sudden onset SOB
Cough
Haemoptysis
Pleuritic chest pain

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Presenting symptoms of pulmonary embolism - large

As above +
Severe central pleuritic chest pain
Shock
Collapse
Acute right heart failure
Sudden death

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Presenting symptoms of pulmonary embolism - multiple small recurrent

Symptoms of pulmonary hypertension

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Signs of pulmonary embolism on physical examination

general

Severity of PE can be assessed based on associated signs

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Signs of pulmonary embolism on physical examination - small

Often no clinical signs

May be some tachycardia & tachypnoea

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Signs of pulmonary embolism on physical examination - moderate
(4)

Tachypnoea
Tachycardia
Pleural rub
Low O2 saturation (despite O2 supplementation)

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Signs of pulmonary embolism on physical examination - massive
(3)

Shock
Cyanosis
Signs of right heart strain
- raised JVP
- left parasternal heave
- accentuated S2 heart sound

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Signs of pulmonary embolism on physical examination - multiple recurrent
(2)

Signs of pulmonary hypertension

Signs of right heart failure

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Investigations for pulmonary embolism

9 types

Well’s score
Bloods
ECG
CXR
Spiral CT pulmonary angiogram 
Ventilation-perfusion (VQ) scan
Pulmonary angiography
Doppler US of lower limb
Echocardiography

Investigations for pulmonary embolism - Well’s score

Used to determine the best investigation for PE

Low probability (Wells 4 or less) - use D-dimer
High probability (Wells >4) - requires imaging (CTPA)

Investigations for pulmonary embolism - bloods

ABG

Thrombophilia screen

Investigations for pulmonary embolism - ECG

May be normal
May show tachycardia, right axis deviation or RBBB
May show S1Q3T3 pattern

Investigations for pulmonary embolism - CXR

Often NORMAL but helps exclude other diagnoses

Investigations for pulmonary embolism - spiral CT pulmonary angiogram
(3)

1ST LINE INVESTIGATION
Poor sensitivity for small emboli
Very sensitive for medium to large emboli

Investigations for pulmonary embolism - VQ scan

Identifies areas of ventilation & perfusion mismatch —> indicates area of infarcted lung

Investigations for pulmonary embolism - pulmonary angiography
(2)

Invasive

Rarely necessary

Investigations for pulmonary embolism - doppler US of lower limb

Allows assessment of venous thromboembolism

Investigations for pulmonary embolism - echocardiography

May show right heart strain

Management of pulmonary embolism | 4 groups

Primary prevention Haemodynamically stable Haemodynamically unstable Surgical or radiological

Management of pulmonary embolism - primary prevention | 3

Compression stockings Heparin prophylaxis for those at risk Good mobilisation & adequate hydration

Management of pulmonary embolism - haemodynamically stable | 4

``` O2 Anticoagulation w/ heparin or LMWH Switch to oral warfarin for at least 3 months - maintain INR 2-3 Analgesia ```

Management of pulmonary embolism - haemodynamically unstable (4)

``` (massive PE) Resuscitate O2 IV fluids Thrombolysis w/ tPA may be considered if cardiac arrest is imminent ```

Management of pulmonary embolism - surgical or radiological | 2

Embolectomy IVC filters - sometimes used for recurrent PEs despite adequate anticoagulation or when anticoagulation is contraindicated

Complications of pulmonary embolism | 4

Death Pulmonary infarction Pulmonary hypertension Right heart failure

Prognosis of pulmonary embolism | 3

30% mortality in those left untreated 8% mortality w/ treatment Increased risk of future thromboembolic disease