A pleural effusion may have more than one etiology

---especially given recent trends toward increasingly frequent complex comorbidities. From a recent review:

Abstract:

Purpose of review: Historically, pleural effusions have been attributed to a single cause. There is growing recognition that a substantial proportion of pleural effusions may have more than one underlying cause. The purpose of this review is to summarise recent findings regarding the diagnosis and treatment of effusions secondary to more than one aetiology.

Recent findings: A recent prospective study identified that 30% of pleural effusions had more than one underlying aetiology. With a rising prevalence of cardiovascular and malignant disease, the incidence of the complex pleural patient is increasing. The use of biomarkers, including pro-B-type natriuretic peptide, have been suggested as a way of identifying contributing disease process.

Summary: Understanding that there are potentially concurrent causes to a pleural effusion is vital in establishing the diagnoses of multiple underlying aetiologies. New diagnostic pathways, with increasing use of biomarkers, will be required to identify the complex pleural effusion. Further studies on whether the targeting of separate aetiologies improves outcomes will help develop future management strategies.