Urinothorax as a Manifestation of Nondilated Obstructive Uropathy Following Renal Transplantation

Urinothorax as a Manifestation of Nondilated Obstructive Uropathy Following Renal Transplantation Joseph Carcilio Jr, MD, and Jose R. Salcedo, MD, FAAP • A 12-year-old patient developed prolonged nondilated urinary obstruction and pleural effusion shortly after undergoing renal transplantation. Renal sonography, angiography, and isotope renography failed to identify· an obstructive process. On the 18th postoperative day, pleural effusion was noted in the right hemithorax, and by day 24, increased perinephric fluid was observed on renal scan. Following a nephrostomy, the pleural effusion resolved and renal function improved remarkably. A ureterovesical junction obstruction and renal pelvis tear that were later discovered were repaired. Whenever a ureteral obstruction is suspected the diagnosis should be pursued vigorously, despite normal radiologic findings, especially in the presence of pleural effusion. Consideration of the possibility of urinothorax in such cases may obviate the need for lung biopsy. © 1985 by The National Kidney Foundation, Inc. INDEX WORDS: Urlnothorax; obstructive uropathy; renal transplant.

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ROLOGIC COMPLICATIONS may pose a serious threat to the renal transplant patient who has a solitary kidney and is receiving immunosuppressive therapy. Such a patient, already predisposed to poor healing and opportunistic infection, can also suffer transplant rejection. This may manifest in a manner similar to that of postrenal obstruction, namely decreased urinary output. Obstruction, complete or partial, may account for 95 % of all urologic complications in transplant allografts. t . 3 In the absence of dilatation, the cause of the obstructive process may be difficult to determine noninvasively. Pleural effusion as a manifestation of urinothorax can be the first radiologic evidence of nondilated obstructive uropathy. Its appearance signals the need for aggressive diagnostic procedures to assess the etiology of obstructive uropathy and to rule out the possibility of infection. MATERIALS AND METHODS Case Report A 12-year-old black female received a renal allograft from a living-related donor. The allograft was placed extraperitoneally over the right iliac fossa. Ureteroneocystotomy was performed following Politano Leadbetter technique . Shortly after surgery the patient developed acute tubular necrosis (ATN) due to reduction in fluid administration following a spuriously high central venous pressure reading . Urine output was minimal for the first 12 days postoperatively (mean 196 mL/dL or 0.02 mL/ kg/h). By the 13th and 14th postoperative days, urine output had improved to 1,280 mLidL (greater than 1.4 mLlkg/h), suggesting that ATN had resolved. On day IS , however, urine output decreased to 70 mLid. Physical examination, with the patient in a supine position, did not show enlargement of the allograft or demonstrate tenderness. The kidney felt firm American Journal of Kidney Diseases, Vol V. No 3, March 1985

without fullness of iliac fossa and there was no edema of the labia or upper thigh. Renal sonogram failed to show any dilatation of the collecting systems although it did reveal a small amount of perirenal fluid . An isotope renal scan showed improvement of blood flow from earlier studies. On the 16th postoperative day, a renal biopsy was performed to rule out rejection. Morphologic studies showed changes compatible with mild ATN with no signs of acute rejection. A repeat sonogram was essentially unchanged except for the presence of a subcapsular fluid collection presumed to be a perirenal hematoma. On the 17th postoperative day, the patient developed a hypertensive encephalopathic crisis. BP rose to 2101120 mm Hg, precipitating the decision for renal arteriogram . This study showed no evidence of decreased blood flow to the allograft or of renal artery stenosis. The following day the patient had a fever of 104 oF. A large right pleural effusion and a right lower lobe pulmonary infiltrate were noted . The allograft was sti ll n'ot felt to be enlarged nor was fullness of the iliac fossa observed. Because the patient was receiving immunosuppressive therapy, an aggressive infectious disease work-up was performed that included bronchoscopy with bronchial brush biopsy followed by a diagnostic and therapeutic thoracentesis. All cultures were negative for bacteria. virus , protozoa, and fungi. Gram stain was normal. Pleural effusion rapidly reaccumulated within 24 hours. Analysis of the pleural fluid revealed the presence of a transudate with a pH of 8, specific gravity of 1.022 , amylase of 12 , WBC 1,413 , RBC 12,444, 47 polys , 13 lymphocytes, and 25 monocytes. Glucose was 130 mg and protein 2 . 1 g/dL. A creatinine determination was not done . On the 25th postoperative day, a third renal sonogram showed an increase in the perinephric fluid. However. this fluid accumulation did not displace the all ograft but rather was a 2From the Department of Nephrology, Children's Hospital Narional Medical Center, Washington. DC, and the George Washington University School of Medicine, Wash ington. DC Address reprilll requests to Jose R. Salcedo, MD, Children's Hospital National Medical Center. I I I Michigan Ave NW, Washington , DC 20010. © 1985 by The NarionaJ Kidney Foundation , Inc. 0272-6386/85/030211-03$03.00/0 211

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em " halo " around it. There was still no ureteral dilatation. Two hundred milliliters of fluid was drained and found to have the characteristics of urine (straw color. pH 5. specific gravity LOIS . I + protein . no bacteria). Surgical exploration reveal ed a urete rovesical junction obstruction and a small' tear in the re nal pelvis. The urete r and renal pel vis tear were repaired and a nephrostomy tube . ureteral stent, and perinephric drainage tubes placed. Urine output rose to 2 mL/kg/h fro m the nephrostomy. Serum creatinine dropped from 12.7 to 2.1 mg/dL within 48 hours. The pulmonary infiltrate and the rapidly reaccumulating pleural effusion resolved within 24 hours . Renal fun ction improved and urine output remained in excess of 2 mL/kg/h.

DISCUSSION

The appearance of a pleural effusion in an immunosuppressed post-renal transplant patient ordinarily leads to aggressive diagnostic work-up and therapy to decrease the potential associated morbidity and mortality.4 When urinary output is insufficient in a posttransplant patient, several clinical facts and laboratory information should be taken into consideration, particularly the time lapsed between the period of oliguria and the surgical procedure itself. If the graft does not function in the early postoperative period, acute tubular necrosis, hyperacute rejection, hypovolemia, obstructive uropathy secondary to occluded Foley catheter, mechanical obstruction of the ureter, or urinary leak should be included in the differential diagnoses. However, late decline in function in a previously satisfactorily functioning graft may be due to rejection , ureteral stenosis, or renal artery stenosis. In general , rejection is characterized clinically by fever, allograft tenderness, swelling , presence of hypertension, and oliguria. Rising serum creatinine and decreased urine sodium concentration may accompany the clinical manifestation. Mechanical obstruction of the transplant ureter and urinary leak at the site of the anastomosis can occur at any time in the postoperative period and is accompanied by abruptly diminished urine output. Generally, ultrasonography is the most effective means of diagnosis since even minimal dilatation of the pelvis can be visualized. When the renal sonogram reveals no dilatation of the collecting systems and the renal scan does not show decreased renal perfusion , one must consider the possibility of an extraperitoneal renal leak, which would allow both a decrease in intracollecting system pressure and a tamponading effect on the ureter and collecting systems . The fact that a renal scan revealed fluid in the extrarenal space in our

patient was probably a preliminary indication of an extraperitoneal leak. The development of pleural effusion was an important second indication; however, it was first necessary to perform a series of diagnostic procedures to rule out an infectious etiology. Once it had been determined that the effusion was a transudate, the necessity for lung biopsy was obviated. Urinothorax has been described in a neonate as a complication of posterior ureteral valves ,5 in patients with hydronephrosis,6 and in a patient with postsurgical ureteral obstruction and bladder laceration. 7 In all three reports, as with our patient, the pleural effusion resolved spontaneously once the urologic obstruction was removed. To our knowledge this case is the first occurrence discovered following renal transplantation. The pathophysiology of urine extending into the pleural cavity offers several hypotheses that imply different pathways . Urine could have escaped from a ruptured collecting system into the peritoneal cavity, as implied in cases of urinary ascites, 12 and reach the pleural cavity through an anatomical defect in the diaphragm , as demonstrated in patients on peritoneal dialysis who develop hydrothorax from dialysate fluid. 13.14 Friedland and co-workers 5 suggested that urine from a ruptured collecting system directly into the retroperitoneal space may reach the pleural space either by direct leakage into the mediastinum and rupture into the pleural space, or drainage via the lymphatics . Corriere et al 6 noted that complete or partial ureteral obstruction in dogs caused increased kjdney lymphatic drainage. They also noted that when a patient 's obstructed kidney is exposed surgically, there is always marked perirenal edema in the retroperitoneal tissues. This sequence of events may lead to urinary ascites as described in Friedland's report. 5 Lemon and HigginsB demonstrated that about 80 % of graphite introduced into the peritoneal cavity of dog s was remov ed via dia phragmatic and retrosternal lymphatics through the normal or paralyzed diaphragm, thereby establishing lymphatic connections between the pleural space, the diaphragm , and the lymph nodes of the kidney. The fact that our patient's transplanted kidney was situated extraperitoneally in the lower right pelvis with its lymphatic connections severed adds another dimension to this observation. While it is possible that the urine communicated directly into

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the retroperitoneal space, it could have dissected its way through it and ruptured into the pleural space. In view of this, the theory of drainage through lymphatics appears less ptausible. The extravasated urine could have been transported via the lymphatic system of the diaphragm. However, since no peritoneal communication existed between the patient's urinoma and the peritoneal cavity, retroperitoneal lymphatic absorption cannot be implied. This patient demonstrated that a pleural effusion may be an early radiologic clue to the presence of nondilated obstructive uropathy, although in most cases urinothorax is diagnosed retrospectively, after the precipitous resolution of the pleural effusion following correction of the obstruction. The diagnosis can be confirmed by measuring the creatinine in the pleural fluid , which will be higher than that of serum. 9 Hydronephrosis as revealed by radiography is the sine qua non in the diagnosis of an obstructed system . Nondilatation can occur in cases of retroperitoneal fibrosis, perirenal and periureteral tumor metastasis,1O and lymphocele. 11 In this case the diagnosis was obscured by the absence of dilatation of the collecting systems. It was not until increasing perinephric fluid prompted an investiga-

tion to rule out the possibility of perirenal abscess in the absence of physical findings suggestive of urinary extravasation , which confirmed the urinary obstruction and renal pelvis tear. We believe, in this case, that this was secondary to increased pressure due to ureterovesical junction obstruction, and not to injury to the renal pelvis during organ harvest. This speculation is supported by the fact that once ATN was resolved on day 13, good urinary output was established for 48 hours. Although retrograde pyelography is difficult to perform in the early transplant period, is invasive and has attended risk, and has been superseded by sonography and renal scan in diagnosing obstruction or urinary extravasation in renal transplant patients. We believe that retrograde pyelography would have established the diagnosis in this case. Thoracic urine extravasation was not considered prior to successful urinary diversion. ACKNOWLEDGMENT We would like to express gratitude to Drs P. Guzzetta, G. Bock, 1. Ruley, E. Kass, S. Karmi, and the medical residents who participated in this patient's care; Linda Harteker, medical writer, who gave valuable advice; and Catherine Evans, who prepared the manuscript.

REFERENCES I . Mundy AR, Podesta ML , Bewick M, et al: The urological complications of 1,000 renal transplants. Br J UroI53:397402 , 1981 2 . Malek GH, Behling DT, Daouk AA , et al: Urological complications of renal transplantation. J Urol 109: 173-176, 1973 3. Sagalowsky AI , RansIer CW, Peters PC , e tal: Urological complications in 505 renal transplants with early catheter removal. I Urol 129:929-932 , 1983 4. Washer GF, Schroler GPJ, Starzl TE, et al: Causes o f death after kidney transplantation. JAMA 250:49- 54, 1983 5. Friedland GW, Axman MM, Lo ve T: Neonatal urinothorax with posterior urethral valves. Br J Urol 44:471474 , 1971 6. Corrierre IN , Miler WT, Murphy JJ : Hydronephrosis as a cause o f pleural effusion. Radiology 90:79-84, 1968 7. Barek LB, Cigtay as: Urinothorax-An unusual pleural effusion . Br J Radiol 48:685- 686, 1975 8. Lemon WS , Higgins GM: Lymphatic absorption of par-

ticulate matter through normal and paralyzed diaphragm: An experimental study. Am J Med Sci 178:536-547 , 1929 9. Stark DD, Shanes JG , Baron RL, et al : Biochemical features of uri nothorax. Arch Intern Med 142:1509-1511, 1982 10. Rascoff JH, Golden RA , Spinowitz BS, et al: Non-dilated obstructive uropathy. Arch Intern Med 143:696-698, 1973 II. Hooke D, Ihle BU, d'Apice A, et al : Ureteric obstruction in the early post-transplant period. Transplant Proc 15:1712-1714, 1983 12. Mondaca R, Wang JJ , Love L, et al: Neonatal ascites associated with urinary obstruction (urine ascites). Radiology 90:1165-1170,1968 13. Scheldewaert R, Bogaerts Y, Pauwles R, et al : Management of a massive hydrothorax in a CAPD patient : A case report and a review of the literature. Peritoneal Dial Bull 2:6972, 1982 14. Leaker BR, Thorn S, Lennox SC, et al: Management of a massive hydrothorax in a CAPD patient. Peritoneal Dial Bull 2: 138 , 1982