SESSION TYPE: Pleural Global Case Report Posters
PRESENTED ON: Tuesday, October 23, 2012 at 01:30 PM - 02:30 PM
INTRODUCTION: Urinothorax is a rare cause of pleural effusion, attributed to the presence of urine in the pleural cavity secondary to obstructive urological pathology. The urine travels into the pleural space via the diaphragmatic lymphatics or through an anatomical defect in the diaphragm. Diagnostic tapping of the pleural fluid aspirate yields a transudate, with an acidic pH, serum creatinine is greater than one and low pleural fluid glucose levels. We report a case of urinothorax in a 55-year-old woman who had a right nephrectomy for renal cell carcinoma (RCC).
CASE PRESENTATION: A 55-year-old woman, with right nephrectomy done for RCC 8 months ago came with complaints of mild dry cough and weight loss. There was no history of tuberculosis, hemoptysis, or chest pain. Relevant findings on physical examination were decreased breath sounds at the base of the right lung, with a dull percussion note. Chest radiograph showed a right moderate pleural effusion. CT chest revealed right pleural effusion, partly loculated, with no significant parenchymal pathology, or mediastinal lymph nodes. A diagnostic pleural tap was done and 100ml of watery pleural fluid was drained. The pleural fluid analysis showed lymphocyte predominance, pleural fluid protein of 0.7 g/dl, lactate dehydrogenase (LDH) of 20 U/L and glucose of 78 mg/dl. Pleural fluid adenosine deaminase (ADA) was normal. Pleural fluid creatinine was 1.5mg/dl, with simulataneous serum creatinine of 1.4mg/dl. Pleural fluid cytologywas negative for malignant cells, and cultures were sterile. A diagnosis of urinothorax was made. The patient was not keen to undergo complete drainage of the fluid, and as she was minimally symptomatic, has been advised regular follow-up.
DISCUSSION: Urinothorax is a rare cause of pleural effusion. Clinically, it is suspected in the setting of prior urological manipulation, when pleural fluid analysis reveals a clear transudate fluid with no alternative explanation, and confirmed with a pleural fluid to serum creatinine ratio > one. Also, patients with urinothorax have low glucose, pH and LDH. The diagnosis requires a high clinical suspicion and should be considered when there is a pleural effusion associated with or seen after a urological condition. Our case has certain interesting features besides the rarity of the diagnosis. This effusion was worked up 8 months after the primary surgery, and had a delayed presentation, leading to mild loculation. The other major concern here was malignant pleural effusion secondary to RCC, which prompted further evaluation, and should be part of the differential diagnosis.
CONCLUSIONS: The diagnosis of Urinothorax requires a high index of suspicion and should be considered whenever a pleural effusion occurs in a patient with obstructive urinary pathology or in patients who have undergone urinary surgical intervention. Most cases are transudate effusion with a pleural fluid-to-serum creatinine ratio greater than one. Drainage of the fluid leading to relief of obstruction is therapeutic in most cases.
1) Light RW. Update : Management of the difficult to diagnose pleural effusion. Clin Pulm Med 2003; 10:39-46.
2) Barek LB, Cigtay OS. Urinothorax - an unusual pleural effusion. Br J Radiol 1975; 48:685-6.
3) Sahn SA. Pleural effusions of extravascular origin. Clin Chest Med 2006; 27:285-308
DISCLOSURE: The following authors have nothing to disclose: Arjun Lakshmana Balaji, Ravindra Mehta
No Product/Research Disclosure InformationFortis Hospitals, Bangalore, India