Renal Failure
ISSN: 0886-022X (Print) 1525-6049 (Online) Journal homepage: http://www.tandfonline.com/loi/irnf20
Yo-Yo Reflux in an Incomplete Duplex System Causing Severe Hydronephrosis in a Patient with Contralateral Renal Agenesis Peter Rehder, Johannes Petersen, Karin J. Hofmann, Claudia Schenk, Thomas Trieb & Bernhard Glodny To cite this article: Peter Rehder, Johannes Petersen, Karin J. Hofmann, Claudia Schenk, Thomas Trieb & Bernhard Glodny (2008) Yo-Yo Reflux in an Incomplete Duplex System Causing Severe Hydronephrosis in a Patient with Contralateral Renal Agenesis, Renal Failure, 30:8, 818-821, DOI: 10.1080/08860220802272605 To link to this article: http://dx.doi.org/10.1080/08860220802272605
Published online: 07 Jul 2009.
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Date: 22 March 2017, At: 15:03
Renal Failure, 30:818–821, 2008 Copyright © Informa Healthcare USA, Inc. ISSN: 0886-022X print / 1525-6049 online DOI: 10.1080/08860220802272605
CASE REPORT LRNF
Yo-Yo Reflux in an Incomplete Duplex System Causing Severe Hydronephrosis in a Patient with Contralateral Renal Agenesis Peter Rehder Yo-Yo Reflux Causing Severe Hydronephrosis
Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
Johannes Petersen, Karin J. Hofmann, Claudia Schenk, Thomas Trieb, and Bernhard Glodny Department of Radiology, Innsbruck Medical University, Innsbruck, Austria
This is a report of a case of a 26-year-old patient suffering from progressive renal insufficiency with a neurogenic bladder disorder due to a lipomyelomeningocele. She had renal agenesis on the left side and grade III hydronephrosis of both segments of a right duplex kidney with a bifid ureter joining further distal to the kidney. Both ureters were dilated. The cause was found to be a yo-yo reflux between the two halves of the kidney. Following bladder augmentation and pyelopyelostomy, renal insufficiency improved to stage III and has now been stable for four years. Due to the contralateral renal agenesis, the case is a unique illustration of the functional effect of the yo-yo reflux and pyelopyelostomy. Keywords yo-yo reflux, incomplete duplex kidney, kidney agenesis, myelomeningocele, renal insufficiency, hydronephrosis
INTRODUCTION Both unilateral renal agenesis (URA), with a frequency of some 1:1100,[1] and ureteral duplication (UD), with a frequency of 1:125 (which is incomplete [IUD] in about half the cases[2,3]), can be associated with various accompanying anomalies. For URA, in addition to cardiovascular, gastrointestinal,[4] and genital malformations,[5] these can include urinary flow disorders in the form of ureterovesical (UVJO) and ureteropelvic junction obstructions (UPJO)[6] or vesicoureteral reflux (VUR).[7] For UD, the anomalies also include VUR[8] and UPJO.[9] This is the
Address correspondence to Dr. Bernhard Glodny, Innsbruck Medical University, Department of Radiology, Anichstrasse 35, 6020 Innsbruck, Austria; Tel.: ++43 512 504 22761; Fax: ++43 512 504 22758; E-mail:
[email protected]
report of a case of a 26-year-old patient with URA on the left side and IUD on the right, whose renal function had deteriorated due to a neurogenic bladder disorder combined with a pronounced yo-yo reflux.
CASE REPORT As a child, the patient had undergone surgical treatment for a lumbosacral lipomyelomeningocele (LMMC). In addition to a widened canalis sacralis apertus, she also had pronounced left convex lumbosacral scoliosis. At the age of six years, she had been successfully treated for urinary incontinence caused by the paralysis of the pelvic floor through the implantation of a hydraulic AMS 800™ Scott urinary sphincter (American Medical Systems, Minnetonka, Minnesota, USA). The atretic left horn of an American Society of Reproductive Medicine class IV bicornuate uterus (BCU), where endometriosis was localized, had to be removed following repeated occurrences of salpingitis and oophoritis. To avoid urinary tract deterioration from excessive intravesical pressure, as well as verified grade IV vesicoureteral reflux and grade III hydronephrosis (see Figure 1), bladder augmentation was later carried out in the form of enterocystoplasty and ureteral re-implantation. However, the patient still suffered from recurring pain on the right flank and progressive renal impairment up to stage IV with creatine clearance of 30 mL/min. Figure 3a shows the pyelopyelostomy in an oblique coronal 15 mm thick-slice maximum intensity projection from a T2-weighted 3D spectral phase coding (T2SPC) MRI sequence (1.5T Siemens Avanto, Erlangen, Germany). Figure 3b shows the insertion of the now only 4 mm-wide ureter into the bladder in an oblique sagittal, fat-saturated thick-slice T2-weighted half-Fourier acquisition singleshot turbo spin-echo sequence (T2-HASTE).
DISCUSSION The URA, combined with an ipsilateral atresia of the Fallopian tube (FT) seen in this patient, is a combination
Figure 2. Retrograde urethrogram, showing (a) the dilated lateral branch of the bifid ureter, draining the upper moiety; (b) a peristaltic wave, transporting the urine into the medial branch; (c) another peristaltic wave transporting the urine back into the lateral branch; and (d) coinciding peristaltic waves in both ureteral branches and vacation of the urine into the bladder.
of malformations from the syndromes of the mesonephric duct induced müllerian deformities.[10] At the beginning of the fourth embryonal week, malformations of the ureteral bud and the mesonephric duct (MND) of one side arise that prevent the müllerian duct (MD) from transversing the MND. This leads to the atresia of the MD and absence of fusion of the müllerian ducts. A didelphys uterus is formed with an atretic FT on the side with renal agenesis.[10] The failure of only the upper segments of the müllerian ducts to fuse and the formation of a BCU, as in this case, is actually a milder form of the same malformation. In this case, the constellation of malformations with a single right duplex kidney allowed the direct observation of the effect of the yoyo reflux on renal function based on serum creatinine levels and its improvement following pyelopyelostomy. The IUD appears to have only little clinical significance for most patients.[11,12] However, in some 25% of patients, nuclear renography shows pathological urodynamic findings,
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P. Rehder et al. (b)
peristalsis to be assessed. The yo-yo reflux and urinary obstruction can also be verified by isotope nephrography or isotope urography,[13] the disadvantage being that morphological information is not precise. By contrast, MR imaging now makes it possible to depict the collecting system precisely, as shown here, as well as to determine the split glomerular filtration rate (GFR).[16] Once the diagnosis is established, therapy may ensue either as ureteropyelostomy[17] or pyelopyelostomy.[18] As demonstrated in this case, this measure may be decisive in preserving remaining renal function.
DECLARATION OF INTEREST Figure 3. (a) The pyelopyelostomy in an oblique coronal 15 mm thick-slice maximum intensity projection from a T2weighted 3D spectral phase coding (T2SPC) MRI sequence, and (b) the insertion of the now slender distal portion of the ureter into the bladder in an oblique sagittal, fat-saturated thick-slice T2-weighted half-Fourier acquisition single-shot turbo spin-echo sequence (T2-HASTE).
consisting of the detection of opposing activity fluctuating between the two kidney moieties. This can be explained by the so-called yo-yo reflux,[13] which is the only known anomaly specific to the IUD.[14] A peristaltic wave moving down one branch of the ureter transports the urine bolus to the fusion site of the ureter, continuing toward the bladder, while at the same time also continuing up the other branch of the ureter. The urine bolus is thus transported into the other moiety of the kidney, which explains the urinary obstruction.[15] The relatively late discovery of the yo-yo reflux phenomenon in this case can be attributed to the fact that for this patient there were two other causes leading to urinary obstruction, namely, the incompetent ureterovesical junction resulting in VUR, and the neurogenic bladder disorder caused by the LMMC, which resulted in chronic elevation of intravesical pressure. Only after the bladder augmentation and ureteral re-implantation ruled out these two mechanisms as an explanation for the urinary obstruction was the yo-yo reflux recognized and treated as the mechanism responsible for the deteriorating renal function. Sonography is well suited for detecting a dilatation of the collecting system, but not for verifying a yo-yo reflux, as the relevant segment of the ureter (i.e., the fusion site) usually cannot be scanned. The absence of dilatation of the collecting system does not necessarily rule out a yo-yo reflux.[15] If there is clinical suspicion of a yo-yo reflux, cinefluorography after intravenous administration of contrast medium[15] is the imaging method of choice, as it displays the morphological situation and enables ureteric
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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