Research Day


Document Type





INTRODUCTION: Urinothorax refers to urine in the pleural space, and is a rare cause of pleural effusion. Urinothoraces can occur secondary to urinary obstruction (e.g. renal calculi), trauma, retroperitoneal inflammation or malignancy, and surgical procedures that produce pleuroretroperitoneal fistulas. As a cause of pleural effusion, they can lead to dyspnea, severe pulmonary complications, and death. Here we present a case of urinothorax secondary to percutaneous nephrolithotomy that resulted in unilateral lung collapse and death. The purpose of this case is to highlight urinothorax as a cause of death, its distinguishing biochemical profile, and its diagnostic features found on autopsy.

MATERIALS: This case was selected from the files of one of the authors, Joseph A. Prahlow, M.D.

CASE REPORT: A 39-year-old female presented to the emergency department with right-sided low back pain and dysuria. Her past medical history was significant for hypertension and recurrent urinary tract infections over the past 2 years. An abdominal and pelvic CT showed a large staghorn calculus occupying most of the upper and middle pole caliceal system of the right kidney. After a urine culture revealed a Proteus mirabilis infection, the patient was treated with levofloxacin as an outpatient.

The patient was then offered percutaneous nephrolithotomy. After upper and lower pole accesses were successfully placed, the patient returned to her hospital room in stable condition. However, she became febrile overnight, and so ampicillin and gentamicin therapy were provided throughout her stay.

On post-operative day (POD) 1, the patient remained febrile and complained of pain in her right lower back and with deep inspiration. CXR was performed and revealed increased right pleural fluid. On POD 2 the patient continued to be febrile and her breath sounds were decreased bilaterally. On POD 3, the patient’s pain decreased and her nephrostomy tube was removed. However, she continued to have difficulty breathing and was found apneic later that evening. Resuscitation was attempted but unsuccessful.

Autopsy revealed marked compression and collapse of the right lung as well as a right-sided 1,200 mL pleural effusion consisting of cloudy yellow fluid which smelled like urine. Examination of the chest wall and right hemidiaphragm revealed a surgical track that originated from the skin of the back at the 10th intercostal space, crossed the right pleural cavity, went through the right hemidiaphragm, and ended in the upper pole of the right kidney. The primary cause of death was listed as complications of right percutaneous nephrolitotomy, with right urinothorax and collapse of right lung.

DISCUSSION: Urinothoraces as a cause of pleural effusion can be missed due to their perceived rarity and a lack of awareness. They can also be incorrectly classified due to their unusual biochemical pattern including transudative characteristics that deviate from Light’s criteria. Furthermore, presenting cases may differ from the established diagnostic criteria resulting in decreased clinical suspicion. Nevertheless, they can cause respiratory failure and death. Thus, when analyzing a case involving urinary tract infections, pleural fluid, and respiratory complications, it is important to keep this diagnosis within the realm of possibility.


  1. Austin A, Jogani SN, Brasher PB, Argula RG, Huggins JT, Chopra A. The Urinothorax: A Comprehensive Review With Case Series. The American Journal of the Medical Sciences. 2017;354(1):44-53. doi:10.1016/j.amjms.2017.03.034.
  2. Garcia-Pachon E, Padilla-Navas I. Urinothorax: Case Report and Review of the Literature with Emphasis on Biochemical Diagnosis. Respiration. 2004;71(5):533-536. doi:10.1159/000080642.
  3. Stark DD, Shanes JG, Baron RL, Koch DD. Biochemical Features of Urinothorax. Arch Intern Med.1982;142(8):1509–1511. doi:10.1001/archinte.1982.00340210107020
  4. Ranjan V, Agrawal S, Chipde SS, Dosi R. Urinothorax: A path, less travelled: Case report and review of literature. Journal of Natural Science, Biology, and Medicine. 2015;6(1):213-216. doi:10.4103/0976-9668.149182.
  1. Salcedo JR. Urinothorax: Report of 4 cases and review of the literature. J Urol 1986; 135: 805-808.

This document is currently not available here.