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Unilateral pleural effusion with suspected coexisting heart failure and pleural malignancy — SCE Respiratory M

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HardBiomarkersUnilateral pleural effusion with suspected coexisting heart failure and pleural malignancySCE Respiratory

A 76-year-old retired shipyard electrician presents with progressive dyspnoea and a large right pleural effusion. He has permanent atrial fibrillation and heart failure with preserved ejection fraction. Before referral, 5 days of intensified diuretic treatment produced a 4 kg weight loss and resolution of peripheral oedema. Serum NT-proBNP is 6100 ng/L and eGFR is 54 mL/min/1.73 m². Echocardiography shows a left ventricular ejection fraction of 58%, severe left atrial dilatation and moderate functional mitral regurgitation. Pleural fluid protein is 34 g/L with serum protein 62 g/L; pleural fluid LDH is 145 U/L with serum LDH 250 U/L and a serum LDH upper reference limit of 240 U/L. Fluid pH is 7.43, bacterial cultures are negative and cytology from an adequate 60 mL sample shows reactive mesothelial cells only. Contrast-enhanced CT after aspiration demonstrates irregular nodular right pleural thickening, including mediastinal pleural involvement. The effusion begins to reaccumulate despite continued diuretic treatment. Which diagnostic strategy is most appropriate?

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Correct answer: D — Proceed to image-guided pleural biopsy while treating heart failure as a possible coexisting contributor

Explanation lettering: C = shown as B · E = shown as C · B = shown as E

The raised serum NT-proBNP, cardiac phenotype and borderline Light’s-criteria exudate after diuresis support a cardiac contribution; diuretic-treated transudates may be misclassified as exudates. However, NT-proBNP must not be interpreted in isolation because more than one cause of a unilateral effusion may coexist. Asbestos exposure, recurrent unilateral fluid and nodular mediastinal pleural thickening create substantial concern for pleural malignancy despite negative cytology. An accessible pleural target should therefore undergo image-guided biopsy while heart failure treatment continues. A is unsafe because a plausible cardiac component does not explain away the malignant pleural features. B is attractive because pleural NT-proBNP has good diagnostic performance, but it is not superior to serum NT-proBNP and would not exclude concurrent malignancy. C is incorrect because pleural tumour biomarkers do not improve sufficiently on cytology and are not recommended for diagnosing secondary pleural malignancy. E is less appropriate because adequate cytology is already negative and cytological sensitivity is limited, particularly for some pleural tumour subtypes; negative cytology should prompt further investigation when suspicion persists. Thoracoscopic biopsy would also be reasonable, particularly if simultaneous fluid control were needed, but image-guided biopsy is appropriate for the demonstrated pleural target.

Reference: British Thoracic Society Guideline for pleural disease (July 2023) — https://www.brit-thoracic.org.uk/document-library/guidelines/pleural-disease/pleural-disease-full-supplement/ British Thoracic Society Guideline for pleural disease (July 2023) — https://www.brit-thoracic.org.uk/document-library/guidelines/pleural-disease/pleural-disease-full-supplement/ A practical approach to pseudoexudative pleural effusions (2023) — https://pubmed.ncbi.nlm.nih.gov/37172787/