Urinothorax: A pleural effusion that might not always be like urine

Abstract

Urinothorax is a rare cause of pleural effusion. So key issues, such as clinical presentation, characteristics of the pleural fluid, diagnostic approach, or management of this disorder, are not well known. We present a patient with a three years’ history of a right-sided recurrent pleural effusion that finally proved to be a urinothorax. The ‘atypical’ presentation of the disease and the non-diagnostic features of the pleural fluid analysis delayed the diagnosis, which was eventually confirmed by renal scintigraphy. We conclude that reliance on pleural fluid biochemical indices to confirm or exclude urinothorax might be misleading. In doubtful cases and when urinothorax is clinically suspected, alternative confirmatory tests, such as renal scintigraphy, may be helpful.