Giant Hydronephrotic Kidney Masquerading as Urinoma: A Rare Presentation with Review of Literature.

Giant hydronephrosis (GH) is a condition in which pelvicalyceal system contains more than 1000 ml of urine. Common causes of GH are uretero-pelvic junction obstruction, renal calculus, abdominal trauma. We are reporting a case of 45 years' male, who presented with abdominal trauma and haematuria and was suspected a urinoma secondary to renal trauma. Examination revealed soft, cystic abdominal lump. Computed tomography of the abdomen revealed grossly hydronephrotic right kidney. The patient was managed by pyeloplasty after renal scan (estimated plasma renal flow- 91.92 ml/minute). Giant hydronephrotic kidney presenting with history of trauma may be confused with post traumatic urinoma.

Introduction

Giant hydronephrosis (GH) is defined in the literature as a renal pelvicalyceal system containing more than 1000 ml of urine. GH is also defined as occupying hemi-abdomen which crosses midline or radiologically, which approaching 5 vertebrae in length. GH is frequently caused by uretero-pelvic junction obstruction. Other common etiologies are calculus disease, abdominal trauma, renal ectopia and malformations.2, 3 GH is more common in male neonates. Clinically, most patients present with abdominal distention and flank pain. Symptoms are usually secondary to compression of nearby structures, including early satiety, intestinal obstruction with vomiting and constipation, respiratory distress, hypertension, renal failure and renal collecting system rupture. We report our case with the uniqueness of GH presenting with abdominal trauma and haematuria which was confused with urinoma secondary to renal trauma.

Case presentation

A 45 years' male presented with history of fall on the ground while walking. He continued his routine activities afterward. He developed right flank pain and hematuria approximately 2 hours after the fall. He presented in a Urology Out-patient Department with history of right flank pain, right flank fullness and gross, total hematuria with the passage of slender clots. On general physical examination, temperature-98.6 F, pulse rate-86/min at the radial artery in supine, respiratory rate-18/min and blood pressure-122/76 mmHg, were recorded. A local examination revealed abdominal distention with soft, cystic lump palpable in the right flank region reaching up to the umbilicus. Hernia sites and external genitalia were normal. Laboratory investigations displayed hemoglobin 9.6 g/dl, total leukocyte count 9500/mm3, blood urea 26 mg/dl, serum creatinine 0.91 mg/dl, serum sodium and potassium 130 and 4.5 mmol/l respectively. Coagulation profile was normal. Urine analysis revealed plenty of red blood cells/high power field and urine culture was sterile. Plain X-ray abdomen had round ground glass shadow over right side of abdomen with leftward displaced bowel shadow. Ultrasonography abdomen revealed a large cystic mass in right renal fossa with internal echogenicity and normal left kidney (Fig. 1a). Contrast enhanced computed tomography of the abdomen revealed grossly hydronephrotic right kidney with blood clots in the pelvi-caliceal system and contrast uptake in rim of the renal parenchyma and normal functioning left kidney (Fig. 1b). On further study, Technetium-99m Ethylene Cysteine (EC) renal scan revealed an enlarged, hydronephrotic, obstructed right kidney with impaired function (split function-22% and estimated plasma renal flow-91.92 ml/min) with normal functioning left kidney (Fig. 2a). Differential diagnosis of GH may be enlisted as-massive ascites, intraperitoneal cystic lesions, retroperitoneal hematoma or cyst, renal or adrenal or pancreatic cyst or pseudocyst and ovarian cyst. Patient planned for open right reduction pyeloplasty after proper counseling. Intraoperative findings were enlarged right kidney with dilated pelvi-caliceal system and stenosed segment approximately 1.5 cm at the pelvi-ureteric junction. No crossing vessels were found. On decompressing pelvi-caliceal system, we drained 7.5 l of urine (Fig. 3a and b). Postoperative period was uneventful. Abdominal drain was removed on post-operative day-3, when 24 hours' output was less than 50 ml. Patient discharged in satisfactory general condition. On follow up visit at 3 months, ultrasonography abdomen revealed hydronephrotic right kidney and Technetium-99m EC renal scan revealed enlarged hydronephrotic right kidney with sluggish drainage (split function-24% and estimated plasma renal flow-109.16 ml/min) with normal functioning left kidney (Fig. 2b).

Figure 1

(a) Ultrasonography abdomen showing large cystic mass in right renal fossa with internal echogenicity and normal left kidney. (b) CECT abdomen revealed grossly hydronephrotic right kidney with blood clots in pelvi-caliceal system and contrast uptake in rim of renal parenchyma and normal functioning left kidney.

Figure 2

(a) Technetium-99m Ethylene Cysteine renal scan revealed an enlarged, hydronephrotic, obstructed right kidney with impaired function with normal functioning left kidney. (b) Post-Operative Technetium-99m Ethylene Cysteine renal scan showing enlarged hydronephrotic right kidney with sluggish drainage with normal functioning left kidney.

Figure 3

Intraoperative image showing dilated pelvis (black arrow) and narrow ureter (a and b).

Discussion

Ureteropelvic junction obstruction leads to impaired flow of urine from the renal pelvis into the ureter resulting in gradual dilatation of pelvicalyceal system and loss of renal parenchyma and function. GH is more common in males usually diagnosed in the early neonatal period. Presentation in adults is uncommon. Our case is unique in presentation, in which GH was detected at the age of 45 years secondary to trauma and haematuria. Widespread use of abdominal ultrasonography made GH as a common entity of neonatal period. GH is a progressive disease and may present with a wide spectrum of symptoms. Diagnosis may be confounded by other cystic or solid mass lesions of the abdomen, leading to abdominal distension like ovarian tumor or cyst, mesenteric cyst, hepatobiliary cyst, retroperitoneal mass or cyst or hematoma, cystic renal tumor, pseudomyxoma, ascites and splenomegaly. In our case GH was diagnosed as urinoma secondary to abdominal trauma, at initial clinical evaluation and abdominal ultrasonography. A definitive diagnosis can be made by cross sectional imaging as computed tomography or magnetic resonance imaging. Management will be determined by residual renal function estimated by either contrast enhancement or tracer uptake on renal scan. In our case reduction pyeloplasty was done based on residual renal function determined by renal scan.

Conclusion

Giant hydronephrosis is usually a neonatal diagnosis, but it should be listed in the differential diagnosis of abdominal distention in adults. Trivial trauma may unveil pre-existing hydronephrosis. Giant hydronephrotic kidney presenting with history of trauma may be confused with post traumatic urinoma. Giant hydronephrotic kidney apparently appearing non-functioning, should be managed by pyeloplasty rather than nephrectomy.

Conflict of interest

The Authors have no conflict of interest.