BTS guidelines for the investigation of a unilateral pleural effusion in adults
- N A Maskell1,
- R J A Butland2,
- on behalf of the British Thoracic Society Pleural Disease Group, a subgroup of the British Thoracic Society Standards of Care Committee
- 1Oxford Centre for Respiratory Medicine, Churchill Hospital Site, Oxford Radcliffe Hospital, Headington, Oxford OX3 7LJ, UK
- 2Department of Thoracic Medicine, Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK
- Correspondence to:
Dr N A Maskell, Oxford Centre for Respiratory Medicine, Churchill Hospital Site, Oxford Radcliffe Hospital, Headington, Oxford OX3 7LJ, UK;
nickmaskell{at}doctors.org.uk
1 INTRODUCTION
Pleural effusions, the result of the accumulation of fluid in the pleural space, are a common medical problem. They can be caused by several mechanisms including increased permeability of the pleural membrane, increased pulmonary capillary pressure, decreased negative intrapleural pressure, decreased oncotic pressure, and obstructed lymphatic flow. The pathophysiology of pleural effusions is discussed in more detail in the guideline on malignant effusions (page ii29).
Pleural effusions indicate the presence of disease which may be pulmonary, pleural, or extrapulmonary. As the differential diagnosis is wide, a systematic approach to investigation is necessary. The aim is to establish a diagnosis swiftly while minimising unnecessary invasive investigation. This is particularly important as the differential diagnosis includes malignant mesothelioma in which 40% of needle incisions for investigation are invaded by tumour.1 A minimum number of interventions is therefore appropriate.
A diagnostic algorithm for the investigation of a pleural effusion is shown in fig 1.
Flow diagram of the investigation pathway for a unilateral pleural effusion of unknown aetiology.
2 CLINICAL ASSESSMENT AND HISTORY
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Aspiration should not be performed for bilateral effusions in a clinical setting strongly suggestive of a pleural transudate, unless there are atypical features or they fail to respond to therapy. [C]
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An accurate drug history should be taken during clinical assessment. [C]
The initial step in assessing a pleural effusion is to ascertain whether it is a transudate or exudate. Initially this is through the history and physical examination. The biochemical analysis of pleural fluid is considered later (section 5).
Clinical assessment alone is often capable of identifying transudative effusions. In a series of 33 cases, all 17 transudates were correctly predicted by clinical assessment, blind of the results of pleural fluid analysis.2 Therefore, in an appropriate clinical setting such as left ventricular failure with a confirmatory chest radiograph, these effusions do …
