Pulmonary Embolism

Question 1

Definition

Answer 1

Occlusion of pulmonary vessels due to a thrombus that has dislodged from
another site.

Question 2

Aetiology

Answer 2

95% DVT, 5% from right atrium in AF.
Other agents that can embolise include
amniotic fluid, mycotic emboli from R IE, gas emboli, tumour emboli and fat emboli.

Question 3

Risk factors

Answer 3

High risk groups include post operative, immobile, OCP, obesity, heart failure
and malignancy.

Question 4

Epidemiology

Answer 4

Common in hospital. Occur in 20% of those with confirmed proximal DVT.

Question 5

Presenting symptoms

Answer 5

Depends on size and site of embolis

• Small: asymptomatic, may have some chest pain
• Moderate: sudden onset breathlessness and chest pain, cough, dyspnea,
haemoptysis.
• Large: all the above plus severe central chest pain, shock, cyanosis, collapse, acure RHF or sudden death
• Multiple small recurrent: pulmonary hypertension

Question 6

Signs on physical examination

Answer 6

Clinical probability assessment (ie. Using Well’s score)

Severity is assessed;

• Small: no clinical signs, may be tachycardic or tachypnoeic.

• Moderate: tachypnea, tachycardia, pleural rub, low saturation O2 despite
being on it.

• Massive PE: hypotension and tachycardia, shock, cyanosis, signs of acute
RH strain (high JVR, strong S2)

Question 7

Investigations

Answer 7

ABG, thrombophilia screen, ACG (mat be normal or tachycardic with RAD and
RBBB, and S2Q3T3 pattern. CXR is often normal but important for DD.

Low probability: use D dimer – sensitive but not specific
High probability: requires imaging

• Spiral CTPA pulmonary angiogram: first line investigation, sensitive for
medium to large emboli

• Pulmonary angiogram: gold standard but rarely used
• VQ scan: using radiolabelled air and blood, indicates VQ mismatch areas.

Doppler USS of lower limb: assess DV

Echocardiogram: RH strain.

Question 8

Management plan

Answer 8

Primary prevention: DVt stockings, movement after surgery, hydration

If provoked and patient haemodynamically stable: O2, anticoagulant or SC
heparin course (3months) and evaluate lifelong coagulation (if provoked and spontaneous, do not give). Analgesic for pain.

• If unprovoked or repeated, start on sapirin or NOAC and continue lifelong.
IF haemodynamically unstable O2, IV fluid, thrombolysis if cardiac arrest is imminent.

Surgical: embolectomy when thrombolysis is contraindicated. IVC filters can be inserted for persistent PE or when anticoagulation is contraindicated.

Question 9

Possible complications

Answer 9

Death,
infarction,
pulmonary HTN,
R heart failure

Question 10

Prognosis

Answer 10

30% death if untreated. 8% if treated.

After the first, increased risk of further thromboembolic disease.