SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Pleural effusions are very common in the field of pulmonary and critical care medicine. Pleural effusions can be caused by cell material pulling fluid into the pleural space or loss of intravascular protein leading to fluid translocation. In rare cases fluid can translocate into the pleural cavity from outside of the pulmonary circulation. If some form of urinary obstruction exists, then even urine can move into the pleural space. This is a case of a patient with xanthogranulomatosis pyelonephritis (XPG) inducing obstruction of urine flow ultimately progressing into a urinothorax and septic shock. CASE PRESENTATION: 71-year-old female admitted for left heart catherization after failed outpatient evaluation. Patient developed elevated creatinine that worsened prior to cardiac catherization. Renal ultrasound in workup of acute kidney injury found large left kidney with staghorn colliculus. Urology advised this could be XPG given severe enlargement and septa formations within the kidney. Percutaneous nephrostomy tube and drain were placed to improve renal function and drain chronic infection. This led to release of enclosed infectious process and rapid development of septic shock. On day of decompensation, abdomen and pelvis CT showed concerns for hemothorax. Bedside ultrasound was performed and showed no true sediment or hematocrit sign. Thoracentesis was performed and fluid creatinine was found to be near identical to serum creatinine with pH not performed. Well over 2L of purulent material was drained from the nephrostomy drain while in the ICU and patient was able to recover from septic shock. Months later patient underwent nephrectomy for XPG due to Proteus mirabilis (PM) staghorn stone formation. DISCUSSION: Urinothorax is common in patients with chronic obstruction of the urinary system (1,3). In the case of this patient the cause was obstruction due to XPG. XPG develops when obstruction causes chronic pyelonephritis (2). In the case of this patient a staghorn calculus formed by PM, the most common causative organism (2), and lead to chronic pyelonephritis that continued to form septa and enlarge the kidney. Urinothorax is rare and likely under reported due to difficulty to recognize (3). It is a transudative effusion with pH of less 7.4 (4) and commonly smells like urine. A pleural fluid to serum creatinine ratio (PF/SC) of 1 is supportive of the diagnosis and is diagnostic at 1.7 (3,4). In our patient this was found to be a transudate effusion with the appearance of urine and ratio PF/SC of 1.7/1.5. CONCLUSIONS: Ultimately both XPG and unrinothorax are rare conditions and should be in physicians’ mind when unilateral kidney enlargement is seen with new large pleural effusions. This case is a good example of complications that can result following the drainage of chronic loculated infections such as XPG. Reference #1: 1.Laskaridis, Leonidas, et al. “Urinothorax-an Underdiagnosed Cause of Acute Dyspnea: Report of a Bilateral and of an Ipsilateral Urinothorax Case.” Case Reports in Emergency Medicine, Hindawi Publishing Corporation, 2012, www.ncbi.nlm.nih.gov/pmc/articles/PMC3542903/. Reference #2: 2.Goodman, M, et al. “Xanthogranulomatous Pyelonephritis (XGP): a Local Disease with Systemic Manifestations. Report of 23 Patients and Review of the Literature.” Medicine, U.S. National Library of Medicine, Mar. 1979, www.ncbi.nlm.nih.gov/pubmed/431402. Reference #3: 3.Casallas, Alexander, et al. “Urinothorax: Case Report and Systematic Review of the Literature.” Urology Annals, Medknow Publications & Media Pvt Ltd, 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC4719522/. 4.Austin, Adam, et al. “The Urinothorax: A Comprehensive Review With Case Series.” The American Journal of the Medical Sciences, Elsevier, 7 Apr. 2017, www.sciencedirect.com/science/article/pii/S000296291730201X. DISCLOSURES: No relevant relationships by Simon Meredith, source=Web Response No relevant relationships by Jacob Moore, source=Web Response No relevant relationships by Ahmed Qadir, source=Web Response No relevant relationships by karan Singh, source=Web Response