A blind-ending ureter with infection due to vesicoureteric reflux with associated renal agenesis: A rare cause of pain abdomen.

We report a 12-year-old male child with an unusual cause of abdominal pain, i.e. a blind-ending ureter with vesicoureteral reflux. The pain improved with antibiotic therapy, implying infection as the cause of pain. This entity is difficult to diagnose clinically, thereby affecting management. Usually, a blind-ending ureter is not filled on intravenous urography (IVU) and the diagnosis is confirmed by retrograde pyelography, which is an invasive procedure. We illustrate the contribution of IVU and computerized tomographic cystography, which has not been reported earlier, in the evaluation of such cases.

INTRODUCTION

There are many causes of abdominal pain in children. Vesicoureteric reflux into a blind ending ureter is an uncommon cause. This entity is usually diagnosed by Voiding Cystourethrography or Retrograde Pyelography. We report a case which was diagnosed by non- invasive investigations i.e Intravenous Urography and CT Cystography. The congenital basis, clinical presentation, investigation and management of such children is discussed.

CASE REPORT

A 12-year-old boy presented with severe pain in the left flank off and on since the last 4 months. There was no history of fever, burning micturition, frequency, dysuria or bowel complaints. There was no significant past history of illness. A general physical and systemic examination was normal. The provisional clinical diagnosis was left-sided ureteric colic.

Laboratory investigations included hemogram, urine microscopy and stool examinations, which were within normal limits. Blood urea and serum creatinine were normal.

Sonography showed an empty left renal fossa. The left kidney could not be localized in the abdomen or pelvis. There was compensatory hypertrophy of the right kidney. No calculus or hydroureteronephrosis was seen in the urinary tract. There was no evidence of a dilated left ureter.

Intravenous urography (IVU) was advised to confirm the absence of left kidney. It revealed the right kidney to be enlarged with normal course and caliber of the right ureter. The left kidney was absent but a film taken at 20 minutes showed a distal left ureter of normal caliber, approximately 15 cm in length, terminating blindly at its proximal end [Figure 1]. The left vesicoureteric junction and the urinary bladder appeared normal. A diagnosis of left renal agenesis/involuted multicystic dysplastic kidney (MCDK) and blind-ending distal left ureter with ipsilateral vesicoureteric reflux was made.

Figure 1

Intravenous urography showing absent left kidney and opacification of blind-ending, lower left ureter, with contrast (arrow)

A voiding cystourethrography (VCUG) did not demonstrate any evidence of vesicoureteral reflux. This may be due to the well-known fact that reflux can be intermittent or because the density of refluxed contrast in the blind-ending ureter may not have been sufficient to be detected by conventional VCUG. To confirm the strong suspicion of reflux, the child was immediately subjected to a limited computerized tomography (CT) scan of the vesicouretric junction. The child did not have to be recatheterized for the same. CT cystogram done on a multislice spiral CT scanner confirmed the presence of vesicoureteral reflux in the blind-ending left ureter [Figure 2].

Figure 2

Computed tomography cystogram shows contrast in blindending lower end of left ureter (arrows), confirming the presence of vesicoureteric reflux

As vesicoureteric reflux is commonly associated with urinary tract infection (UTI), he was treated empirically with cefixime 10 mg/kg and became asymptomatic within 48 hours. The parents have been counseled about the need for elective surgery, i.e. excision of the blind-ending refluxing ureter.

DISCUSSION

A blind-ending ureter is a rare congenital anomaly. It may be associated with renal agenesis or MCDK.

In the normal fetus, the ureter develops as a bud from the mesonephric duct and eventually migrates toward and fuses with the metanephros or renal plate. In rare cases, the ureteral bud fails to fuse with the renal plate and results in a blind-ending ureter.[1] Renal agenesis is generally thought to result from lack of induction of the metanephric blastema by the ureteral bud,[2] which may be secondary to ureteral bud maldevelopment.

Unilateral renal agenesis is usually asymptomatic when it occurs as an isolated anomaly.[2] Patient with a blind-ending ureter may present with a vague abdominal pain of several months duration, but not associated with colic; also, no history of urinary complaints may be elicited.[2] A blind-ending ureteric bud has a higher than normal incidence of vesicoureteric reflux and therefore may get acutely inflamed in an infection. It may result in hematuria, calculus formation or UTI.[1] Systemic examination and routine urine examination may be normal.

Routine sonography shows an empty renal fossa with ipsilateral kidney not localized in the abdomen or pelvis. There will be a compensatory hypertrophy of the contralateral kidney. A dilated distal third of ureter may be demonstrated with a normal vesicoureteric junction.[2]

Excretory urography alone is usually insufficient to show a blind-ending ureter.[1] Only four cases of blind-ending ureteral duplication have been demonstrated by excretory urography alone, usually employing a high-dose technique.[3] These duplicated blind-ending ureters were identified due to the presence of uretero-ureteral reflux. Most cases require retrograde pyelography for demonstration.[4] However, in our case, a non-duplicated, i.e. single blind-ending ureter was detected on IVU and, that too, without employing a high-dose technique. This was probably possible due to reflux of contrast from the urinary bladder into the blind-ending left ureter.

Radionuclide imaging may demonstrate this entity as a persistent focus of radioactivity in the region of ureter.[1] However, the differential diagnosis would include a ureteral diverticulum and localized ureteral rupture, both of which can be differentiated by history, clinical findings and/or excretory urography.

A blind-ending ureter possesses the same histological layers as a normal ureter and, by definition, it is at least twice as long as it is wide, to differentiate it from a ureteral diverticulum.[1]

CT urography may show absence of ureter or absent filling of a dilated residual ureter.[2] In our case, conventional VCUG failed to demonstrate the blind-ending ureter, while CT cystography revealed contrast in the blind left ureter, secondary to vesicoureteric reflux. This is because multislice CT has a higher contrast resolution.

Management of these cases requires resection of the blind ureter.[56] Traditionally, open surgical resection of a blind-ending segment is performed, but laparoscopic retroperitoneal resection is a viable and less invasive alternative.[7]

CONCLUSION

In a child with an absent kidney, vesicoureteric reflux into an ipsilateral blind-ending ureter, causing UTI, should be considered amongst the unusual causes of pain abdomen. The role of noninvasive investigations like IVU and CT cystography in making this diagnosis is highlighted.