FFinalistSouthampton · 2027
Acute care
AKT · Acute care/Cardiac & respiratory

Pulmonary embolism

Venous thromboembolus lodging in the pulmonary arteries

Overview

Obstruction of the pulmonary arteries by thrombus (usually from a DVT). Presentation ranges from pleuritic pain/breathlessness to massive PE with haemodynamic collapse. The Wells score directs whether to image or D-dimer first; massive PE may need thrombolysis.

Recognise

  • Pleuritic chest pain, dyspnoea, haemoptysis, tachycardia, hypoxia
  • Risk factors: surgery/immobility, malignancy, pregnancy/postpartum, oestrogen, prior VTE, thrombophilia
  • Massive PE: hypotension, syncope, right-heart strain

Red flags

  • Haemodynamic instability (massive PE) → consider thrombolysis; pregnancy (alters imaging choice)

Differentials & how to tell them apart

Acute coronary syndromecentral crushing pain, ischaemic ECG/troponin pattern
Pneumoniafever, productive cough, consolidation
Pneumothoraxsudden pain, hyper-resonance, reduced breath sounds
Anxiety/hyperventilationno hypoxia, no risk factors

Investigations

Two-level Wells score. PE likely → CTPA (V/Q if renal impairment/pregnancy). PE unlikely → D-dimer (if positive, image). ECG (sinus tachy, S1Q3T3), ABG, troponin/echo for strain.

Management

Anticoagulate (DOAC first-line); massive PE with shock → thrombolysis

  1. 1Calculate the two-level Wells score. PE likely → CTPA and interim anticoagulation; PE unlikely → D-dimer, image if positive.Gate: Massive PE with haemodynamic instability (hypotension) → thrombolysis (alteplase); in pregnancy use LMWH and V/Q or CTPA, not a DOAC
  2. 2Continue anticoagulation (DOAC) — duration by provoked vs unprovoked; investigate for cancer/thrombophilia as indicated.
DOAC (apixaban/rivaroxaban) — first-line anticoagulation for most
LMWH — pregnancy, or while awaiting imaging if high suspicion
Thrombolysis (alteplase) — massive PE with haemodynamic instability

Key points

Wells decides the pathway; D-dimer is only useful when PE is unlikely (rule-out). Pregnancy needs LMWH (DOACs/warfarin avoided) and adjusted imaging.

Monitor & prognosis

O2/haemodynamics acutely; anticoagulation efficacy/bleeding; review duration.

Good if treated; massive PE carries high mortality.

Source: NICE NG158 (venous thromboembolism)