Urinothorax: A path, less travelled: Case report and review of literature.

Urinothorax is a very rare occurrence of urine in the pleural space. Urinothorax can occur as a consequence to percutaneous nephrolithotomy (PCNL), ureterorenoscopic lithotripsy (URSL) or shock wave lithotripsy (SWL). We herewith report a rare case of Urinothorax in a 35 years old male patient and discuss its current knowhow and clinical management.

INTRODUCTION

The urinothorax or collection of urine in the pleural space is a rare and unusual cause of pleural effusion. This entity was first being described as a consequence to ureteral obstruction in dogs.[1] The etiologies of urinothorax could be traumatic or obstructive.[2] It may also occur after iatrogenic intervention such as percutaneous nephrolithotomy (PCNL), ureterorenoscopic lithotripsy or shock wave lithotripsy. For proper management of urinothorax, etiologies need to be understood carefully. Awareness of this condition and the appropriate diagnostic tests, performed early, is the most important for the diagnosis and treatment of urinothorax.[3] We here discuss a rare case of urinothorax arising after left PCNL performed for removal of left renal stone and its management.

CASE REPORT

A 35-year-old male was presented to outpatient department with the complaint of pain in left flank region for 1 month. Ultrasound examination revealed small contracted right kidney with stone and hydronephrotic left kidney with multiple calculi. His intravenous urography suggested poor contrast excretion from the right kidney with normal functioning left kidney with multiple superior calyceal stones [Figure 1]. Diethyl triamine penta acetic (DTPA) renogram further revealed poorly functional right kidney (glomerular filtration rate-18%) and normal functioning left kidney. Preoperative workup including renal function and chest X-ray was normal [Figure 2a]. Patient was taken up for left PCNL under general anesthesia. Superior calyceal supracostal puncture above 11th rib was done under fluoroscopic guidance. Tract dilated until 24 Fr, stones fragmented with lithotripter and near complete clearance was achieved. A 5.5/26 Fr Double J (DJ) stent and 16 Fr nephrostomy drain were placed. Patient tolerated the procedure well without any significant intraoperative bleeding.

Figure 1

Intravenous urogram

Figure 2

Chest X-ray (a) at admission, (b) postoperative day-2 showing left pleural effusion, (c) post intercostal drain insertion, (d) at the time of discharge

Postoperatively, he developed mild pain over left hypochondrium and back with difficulty in breathing. His peripheral oxygen saturation was 85%. Chest X-ray was done, which revealed mild left pleural effusion. However patient stabilized after supportive treatment. On second postoperative day, nephrostomy drain was removed, following which his condition deteriorated. He complained of pain again over the same site with difficulty in breathing and diminished urine output. Fluid challenge along with diuretic was given which resulted in increased respiratory distress without improvement of urinary output. Ultrasonography chest revealed left moderate pleural effusion and 600 ml pleural fluid was aspirated. The patient condition deteriorated again at night, repeat chest X-ray [Figure 2b] showed recurrence of effusion on the left side for which intercostal drain was placed [Figure 2c]. A volume of 2 L of mild hemorrhagic fluid was drained immediately followed by 1.6 L until the next morning. The analysis of pleural fluid was suggestive of transudate fluid with ammonical odor and an increased pleural fluid to serum creatinine ratio (9:1). Abdominal X-ray was performed to confirm DJ stent position, which revealed displaced DJ stent in the urinary bladder [Figure 3]. Patient was taken into the operation theater and left retrograde pyelogram revealed contrast leak from superior calyceal system along with evidence of numerous clots in the left ureter on ureteroscopy. A 5.5/26 Fr DJ stent was placed again. Urinary output increased after stenting and the chest drain decreased gradually with complete resolution on 12th postoperative day. Intercostal drain was removed with chest X-ray showing full expansion [Figure 2d]. Patient was discharged on 15th postoperative day. DJ stent and Foleys catheter were removed 1 week after discharge.

Figure 3

Displaced Double J stent

DISCUSSION

Urinothorax is the presence of urine in the pleural space, which is a very unusual condition.[4] Several possible etiologies are proposed, with obstructive uropathy with hydronephrosis and disruption of the diaphragm by blunt abdominal trauma being the most common cause.[5] The other etiologies reported are percutaneous endoscopic renal procedures, retroperitoneal inflammatory processes, polycystic renal disease, ureteral valves, extracorporeal lithotripsy, and intra-abdominal compression from gravid uterus or lymphomatous masse.[267] Direct collection of the extraperitoneal urine into the pleural space or collections by lymphatic drainage are the proposed pathologic mechanism of development of urinothorax.[8] In the present case, urinothorax resulted as a direct complication of supracostal puncture during PCNL, as preprocedural chest X-rays were reported as normal. Most of cases of urinothorax report symptoms of cough, chest pain, dyspnea or asymptomatic.[2] Nevertheless, one should be suspicious enough to diagnose this condition earliest when the patient develops symptoms. A chest X-ray may show mild to moderate collection on the ipsilateral side, but contralateral involvement has also been reported.[48] Our case presented with massive unilateral effusion on the ipsilateral side. The diagnosis was confirmed by analysis of pleural fluid. Grossly, the fluid was clear to pale yellow in color with distinctive ammonia odor. The nature of fluid is transudative. The raised pleural fluid creatinine to serum creatinine ratio is a diagnostic feature [Table 1].[237] Other inconsistent markers are normal to raised lactate dehydrogenase low protein and glucose content, low pH and presence of pleural fluid carcino embryonic antigen.[2] Renal scans are preferred choice of radiological investigation with mercaptoacetyltriglycine scans preferred over DTPA scans and invasive tests are rarely required.[9] The treatment is directed to correction of underlying pathology and removal of collected effusion.[10] The minor effusion with asymptomatic patients may require only needle drainage, but thoracostomy and tube placement (in case of recurrent or large effusions) and partial nephrectomy has also been reported (preferably in cases of nonfunctioning kidneys).[81011] High index of suspicion for the early diagnosis of urinothorax and proper management targeted at the underlying cause is necessary so that a good outcome can be obtained as in this case.

Table 1

Analysis of studies on urinothorax