Blockage of a pulmonary artery by an embolus

Aetiology

• A PE is usually (95%) the result of a DVT - Virchow’s triad
• Atrial fibrillation can cause PE - blood clots form in the atria due to stasis, and then embolize to the pulmonary arteries
  • Thrombosis will be arterial not venous - arterial clots contain higher amounts of platelets whereas venous clots have higher amounts of fibrin

Clinical features

Symptoms

• Dyspnoea - often acute onset
• Pleuritic chest pain
• Symptoms of DVT - leg pain, swelling etc.
• Collapse (/sudden death)
• Fever
• Haemoptysis

Signs

• Tachycardia
• Hypoxia
• Cyanosis
• Low BP
• Signs of right heart strain may be seen in sub-massive PE: loud P2, elevated JVP, parasternal heave

Investigations

Diagnostic workup