- Pulmonary thromboembolism is a complication of deep vein thrombosis.
- If untreated there is a 30% mortality. If treated the mortality falls to <5%.
- Highest cause of maternal mortality in pregnancy.
- Associated with malignancy, immobility, thrombotic haematological disorders.
- D-Dimer blood test is very sensitive, but not very specific.
- Treatment is aimed at preventing further emboli.
- Patients with recurrent emboli may require long-term, sometimes lifelong, warfarin.
- Rarely emboli may represent fat emboli (following extensive lower limb/pelvic trauma) or tumour emboli. Fat embolus is rare and a distinct phenomenon. Patients present with acute SOB/collapse and dramatic CXR changes (extensive bilateral air space opacification similar to ARDS – adult respiratory distress syndrome).
- Cough, haemoptysis.
- Pleuritic chest pain.
- Deep leg vein thrombus.
- Hypotension, tachycardia.
- Pulmonary arterial hypertension with right heart strain and failure.
- Sudden death.
- CXR – may be normal.
- Other radiographic features of pulmonary embolic disease include:
Fleischner’s sign – local widening of pulmonary artery due to distension from clot.
Hampton’s hump – segmental pleurally based wedge-shaped opacity representing a pulmonary infarct.
Westermark’s sign – peripheral wedge-shaped lucency due to focal lung oligaemia.
- Ventilation/perfusion scan – mismatched perfusion defects.
- CT scan (CTPA) – filling defects within the pulmonary arterial tree on contrast-enhanced imaging. There may also be mosaic perfusion with reduced vasculature in the lucent areas.
- Pulmonary angiography – filling defects.
- Echocardiography – dilated right atrium with right ventricular hypertrophy and pulmonary arterial hypertension.
- The clinical presentation and CXR features are often non-specific and a number of conditions may mimic embolic disease (e.g. pneumothorax, infection, asthma and lung neoplasms).
- Anticoagulation if PE is confirmed.
- Extensive thromboemboli with hypotension and tachycardia may require treatment with thrombolysis.