Case Presentation:
A 62‐year‐old female with a history of aortic valve replacement treated with warfarin presented with increased urinary frequency and hematuria; she was diagnosed with a right renal calculus by abdominal CT. She was admitted and underwent a right percutaneous nephrolithotomy and placement of a percutaneous nephrostomy tube. On post‐operative day 8, she complained of worsening dyspnea, non‐radiating substernal chest pain, mild nonproductive cough, orthopnea and mild nausea. Physical examination revealed hypoxia to 82% on room air, tachypnea, decreased breath sounds in the right lower lung field, and bloody output from the nephrostomy tube. The nephrostomy tube was removed and a chest roentogram showed a large right pleural effusion. The patient underwent a right thoracentesis with removal of 1.1 liter of malodorous, bloody fluid with low protein and high LDH; she was diagnosed with a urinothorax.
Discussion:
A urinothorax results from an accumulation of urine in the pleural space and should be considered in patients with a pleural effusion in the setting of obstructive uropathy; trauma from an attempted percutaneous nephrostomy, kidney biopsy, or lithotripsy; urinary tract malignancy; or a renal transplant. Initially, leakage of urine into the retroperitoneal space forms a urinoma; urine then moves directly into the pleural cavity due to either an anatomic diaphragmatic defect or via lymphatic drainage into the mediastinum. The urinothorax commonly occurs ipsilateral to the obstructed kidney, but it should not occur solely due to a unilateral obstruction as long as the contralateral kidney function is normal. Pleural fluid analysis typically reveals both a low pH and a transudative effusion, but a high LDH can occasionally result in the misclassification of it as an exudative effusion. Renal scintigraphy will demonstrate leakage of tracer from the urinary tract into the pleural space. Once the renal obstruction is relieved, the urinothorax typically resolves.
Conclusions:
Although obstructive renal disease is common, urinothorax is less frequently recognized. Severe dyspnea, although present in this case, is very uncommon and has been reported only a few times in the literature.