BLADDER OUTLET OBSTRUCTION LEADING TO URINOTHORAX

Abstract

SESSION TITLE: Disorders of the Pleura 2 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 pm - 02:15 pm INTRODUCTION: Urinothorax is the presence of urine in the pleural space as a result of genitourinary (GU) trauma or obstructive uropathy. Injury in the GU tract results in urine extravasation into the peritoneal or retroperitoneal space, which then enters the pleural space via the diaphragm or lymphatics. Pleural fluid analysis greatly aids in the diagnosis. Dyspnea is often the presenting symptom. Less than seventy cases of urinothorax have been identified in the literature. CASE PRESENTATION: A 78-year old male presented with fatigue, dyspnea, suprapubic pain, and urinary incontinence for the past two weeks. Routine workup revealed AKI and hyperkalemia. The patient had a history of CVA, hypertension, hyperlipidemia and chronic kidney disease. Computed tomography (CT) of abdomen/pelvis revealed an enlarged prostate with bladder outlet obstruction and severe hydroureteronephrosis. Additionally, a large right sided pleural effusion with near collapse of the right lower lobe was noted [Figure 1]. A thoracentesis was performed and 2020 mL of simple, serous fluid was drained. The transudative fluid had a pH of 7.2, total fluid protein < 1.0 and fluid to serum creatinine ratio >1.0, highly suggestive of urinothorax. His dyspnea resolved after thoracentesis. He ultimately required bilateral percutaneous nephrostomy tubes with improvement in his renal function and no recurrence of urinothorax or other pleural effusion as seen on subsequent imaging. Given his known obstructive uropathy, no further workup was indicated for etiology of urinothorax. DISCUSSION: Urinothorax is a rare cause of pleural effusions that is caused by GU trauma, including iatrogenic instrumentation or transplant, or obstructive uropathy, including mechanical obstruction or bladder outlet obstruction. In both etiologies, the mechanism involves high pressures that result in translocation of urine into spaces that ultimately connect with the pleural space. Diagnosis involves identifying a pleural effusion and subsequently testing pleural fluid via thoracentesis. This rare and under diagnosed condition presents as the only transudative pleural effusion with pH <7.40. Other abnormal labs include a pleural fluid to serum creatinine ratio >1.0 and/or elevated LDH in pleural fluid. The fluid to serum creatinine ratio is the most specific feature of urinothorax. CT or ultrasound imaging can help discover the cause. Although there is an association with nephrostomy, our case was due to obstructive uropathy as it was diagnosed prior to intervention. CONCLUSIONS: Urinothorax is a rare condition that can result from abdominal trauma, genitourinary tract injury or obstructive uropathy. Recognition of this rare entity is important to allow for timely alleviation of obstruction, relieve symptoms, and prevent recurrence; as was the case with our patient. Reference #1: Austin, Adam & Navin Jogani, Sidharth & Bradley Brasher, Paul & Gupta Argula, Rahul & Huggins, John & Chopra, Amit. (2017). The Urinothorax: A Comprehensive Review with Case Series. The American Journal of the Medical Sciences. 354. 44-53. Reference #2: Toubes ME, Lama A, Ferreiro L, et al. Urinothorax: a systematic review. Journal of Thoracic Disease. 2017;9(5):1209-1218. https://doi.org/10.21037/jtd.2017.04.22. DISCLOSURES: No relevant relationships by Michael Bergman, source=Web Response No relevant relationships by Ryan Richard, source=Web Response No relevant relationships by Jigna Solanki, source=Web Response