Urinothorax: A Rare Complication of Urinary Tract Obstruction Secondary to Benign Prostatic Hyperplasia

Abstract

SESSION TITLE: Pleural Effusions SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Urinothorax is a rare cause of pleural effusion, documented mostly in case reports. We report a case of a man who developed a left-sided urinothorax in the setting of urinary tract obstruction. CASE PRESENTATION: A 75-year-old male with a history benign prostatic hyperplasia (BPH) presented to the ED with 2 weeks of oliguria and lower abdominal pain. A month prior to his presentation, he had a normal serum creatinine at a routine medical visit. In the ED, vital signs were normal, with physical examination positive for abdominal tenderness and distention. Labs were significant for serum creatinine of 6.65 mg/dL and BUN of 75 mg/dL. A renal and bladder ultrasound showed a distended bladder, along with bilateral moderate hydronephrosis, prompting foley catheterization subsequently draining 3 liters of urine with improvements in abdominal pain and serum creatinine to 4.28 mg/dL. A portable chest X-ray was also obtained in the ED, revealing a left sided pleural effusion. The patient denied of any respiratory symptoms. A follow-up PA/Lateral chest X-ray on the next day showed improvement in the effusion. The only intervention the patient had received at the time was the foley catheter insertion to alleviate urinary obstruction. A thoracentesis was performed revealing straw colored fluid. Pleural fluid analysis revealed: LDH of 140 U/L, protein 2.3 g/dL, pleural creatinine 1.5mg/dL, glucose 130mg/dL, amylase 70 U/L, triglyeride 69 mg/dL, pH of 7.55, WBC 250, RBC 20, and cytology was negative for malignant cells. Concurrent serum protein was 6.5 g/dL, and an LDH of 175 U/L. Serum and pleural creatinine ratio was 2.85. Given the clinical history, and pleural fluid analysis, the patient was diagnosed with urinothorax as a result of obstructive uropathy. DISCUSSION: Causes of urinothorax found in literature are mostly consequences of obstruction, trauma, and iatrogenic complications post-surgery. Respiratory symptoms may or may not be present. Urinothorax occurs as a result of urinary leakage within the retroperitoneum passing through a potentially anatomically compromised diaphragm. Eventually the urine reaches the pleural space via the lymphatic system leading to a build-up of fluid. Diagnosis requires pleural fluid analysis showing elevated pleural to serum creatinine ratio greater than 1. The analyzed pleural fluid can meet either the exudative and transudative light's criteria, due to occasionally elevated LDH levels as seen in our patient. Treatment involves alleviating the underlying cause, and drainage of pleural fluid if necessary. CONCLUSIONS: High index of suspicion for the early diagnosis and proper management of the underlying cause is necessary for a good outcome, which in our case is the obstructive uropathy. Reference #1: Brown B, Trotter C, Cox P, Hanlon C. Urinothorax: A rare cause of pleural effusion. W V Med J. 2011;107:16-7. DISCLOSURE: The following authors have nothing to disclose: Katherine Lopez, Di Pan, Franco Vallejo Garcia, Wen Zhang No Product/Research Disclosure Information