Urinothorax and pseudo-azotemia following total abdominal hysterectomy: a case report

Background: Pleural effusion is a common pulmonary condition affecting millions of individuals worldwide. Pleural effusion of extravascular origin (PEEVO) pertains to a pleural effusion that does not originate from the pulmonary vasculature. True prevalence of PEEVO, such as urinothorax, is unclear in view of the absence of clear diagnostic criteria. However, it has been observed to follow a bimodal age distribution, with a higher frequency in the age groups of 41-50 and 61-70 years. Additionally, it was more likely to have a unilateral right-sided presentation and occupy over two-thirds of the hemithorax. Pseudo-azotemia is a condition that causes elevated blood urea nitrogen (BUN) and creatinine (Cr) levels without actual kidney dysfunction. Case Description: We report an uncommon case of right-sided urinothorax in a middle-aged female presenting with symptoms of postoperative ileus after undergoing total abdominal hysterectomy. She subsequently developed pseudo-azotemia and right-sided pleural effusion. The patient was successfully treated with thoracentesis and chest tube placement, with prompt resolution of effusion and pseudo-azotemia. Conclusions: We aim to provide insights into the underlying pathophysiology as well as diagnostic and therapeutic modalities of urinothorax. Prompt recognition and intervention can improve outcomes by decreasing respiratory complications and shorten or avoid intensive care unit stays. Physicians should consider PEEVO within their differential when intrathoracic causes of pleural effusion have been excluded and be equipped to manage it appropriately.