Urinothorax

Urinothorax (pl. urinothoraces) means urine in the fluid-filled cavity that surrounds the lungs.^[1] It is a rare case of pleural effusion secondary to obstructive uropathy whereby urine forms a collection in the pleural cavity. The urine arrives in the pleural space either retroperitoneally under the posterior diaphragm, or via the retroperitoneal lymphatics. It remains a rare, possibly under-diagnosed, differential in the case of transudative pleural effusion.

Handa et al,^[2] described 47 cases between 1967 and 2007, noting that it was more prevalent in males, generally ipsilateral to the obstruction, and in most cases relieved by clearance of the obstruction.

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