| ORIGINAL REPORTS |
From the Departments of Urology1, Divisionof Pediatric Urology and the Department of Radiology2, Divisionof Pediatric Radiology, Bowman Gray School of Medicine Wake Forest UniversityWinston-Salem, North Carolina
ABSTRACT
We report a case of VURD syndrome in a three day old neonatewho was diagnosed with hydronephrosis on a prenatal ultrasound. Severetortuosity and dilation of the upper urinary tracts in the presence ofprogression of hydronephrosis or a persistently elevated creatinine mayfavor a proximal urinary diversion rather than primary valve ablation orcutaneous vesicostomy. Because of a persistently elevated serum creatinine,a nonfunctioning kidney with grade 4/5 vesicoureteral reflux and worseningcontralateral hydronephrosis despite lower tract drainage, a left cutaneouspyelostomy was performed, contralateral to the kidney involved with VURD.Postoperatively the serum creatinine stabilized at 1.0 mg/dl and decreasedto 0.3 mg/dl at one month of age.
Introduction
Rittenberg et al. described in 119 patients the genitourinaryabnormalities of the posterior urethral valve, unilateral vesicoureteralreflux, and renal dysplasia as the VURD syndrome.1 We reporta case of VURD syndrome in a three day old neonate.
Case Report
A pregnant twenty-four year old white female with no knownmedical disease was found to have a fetus who had oligohydramnios and mildbilateral hydronephrosis at 30 weeks gestation. After subsequent pre-termlabor, the patient was born at 32 weeks by vaginal delivery and weighed2.2 kg with no abdominal masses appreciated on physical exam. A postnatalultrasound demonstrated severe bilateral hydronephrosis. Laboratory evaluationincluded a urinalysis which was normal and serum electrolytes which werenormal except for a creatinine of 1.8 mg/dl. A voiding cystourethrogramdemonstrated grade 4 vesicoureteral reflux on the right, a thickened bladderwall, and posterior urethral valves (Fig.1) and (Fig. 2).A 5 French feeding tube was inserted to drain the bladder.
Twenty four hours after the insertion of the urinary catheter,the patient's repeat creatinine was 1.7 mg/dl. A repeat ultrasound showedstable hydronephrosis on the right, increase hydronephrosis on the left,and a decompressed bladder. A renogram demonstrated no function on theright and good uptake of the radioactive isotope on the left with delayedexcretion even after the administration of Lasix(Fig.3).
Following a left percutaneous nephrostomy for suspectedsupravesical obstruction, the patient's creatinine decreased to 1.4 mg/dl.An antegrade nephrostogram with an open urinary catheter drainage demonstratednon-obstructed flow into the bladder(Fig.4). Due to the persistently elevated creatinine and the increased riskof infections with prolonged intubated urinary drainage, the patient wastaken to the operating suite for a left cutaneous pyelostomy and left renalbiopsy. The biopsy showed immature kidney with no specific diagnostic histopathologicchanges. Postoperatively, the patient's creatinine stabilized at 1.0 mg/dl.At the patient's one month follow-up, serum creatinine was noted to be0.3 mg/dl.
Discussion
Prenatal ultrasonography permits in utero diagnosis ofhydronephrosis prior to clinical evidence of an obstructive uropathy duringthe postnatal period.2,3 Sonography is repeated postnatallyto confirm the presence of hydronephrosis. A voiding cystourethrogram (VCUG)is required to complete the evaluation of hydronephrosis.2 Vesicoureteralreflux as demonstrated by VCUG is present in approximately 50% of the patientswith posterior urethral valves.2 Specifically, unilateral refluxwas present in 23.9% with the left ureter affected twice as often as theright.4 Reflux in association with posterior urethral valvesimplies a worse prognosis for the involved kidney.5 However,the nonrefluxing renal unit is protected from the increase hydrostaticpressure in the collecting system by the "pop-off" effect of the refluxingrenal unit.3-6 Twenty five to thirty percent of VURD patientshave low grade vesicoureteral reflux (grade 1-3) the consequences of highintravesical pressures. This reflux will usually resolve following valveablation.7 However, the high grades of reflux which our patienthad tend to be associated with nonfunctioning, dysplastic kidneys. We didnot obtain a pathologic diagnosis of renal dysplasia of the right kidneywhich had the high grade reflux. However, the radiologic studies are consistentwith a dysplastic right kidney.
The exact cause of the VURD syndrome is unknown. However,Henneberry, Stephens, and Mackie theorized that it was not the reflux thatcaused the renal dysplasia but rather the abnormal position of the uretericbud arising from the Wolffian duct.5-7 The excessive lateralizationof the ureteric bud from the mesonephric duct during embryological developmentleads to the formation of a peripheral portion of the metanephric blastemaresulting in the development of a dysplastic renal unit.4,5,7The lower end of the ureter migrates into a more lateral position in theforming bladder and remains laterally ectopic with an inadequate submucosaltunnel that is too short to prevent reflux.7
Immediate treatment of the VURD syndrome consists of drainingthe urinary bladder through an indwelling urethral catheter (5 or 8 Frenchfeeding tube) and intravenous fluid therapy to correct electrolyte abnormalities,dehydration and metabolic acidosis. Serum creatinine should be closelyobserved. If the creatinine falls significantly below 1.0 mg/dl and thereis only mild or moderate upper tract dilation in a relatively well baby,valve ablation should be considered.5 Duckett found that patientswith a nadir creatinine below 0.8 mg/ dl were unlikely to develop chronicrenal failure and ESRD, end stage renal disease.3 However, ifthe bladder is small and there is significant tortuosity of the uretersand hydronephrosis which was present in our patient, a simple valve resectionmight not be enough. Therefore, in such patients it is preferable to beassured that the bladder remains empty by employing a simple vesicostomy.5Worsening hydronephrosis and persistent elevation of serum creatinine inour patient prompted us to obtain a radionuclide renal scan to delineatethe functional status of the kidneys. In such patients with worsening hydronephrosisand/or persistently elevated creatinine, temporary proximal diversion shouldbe considered such as percutaneous nephrostomy tube, high ureterostomy,or cutaneous pyelostomy to assure adequate drainage from the renal unit.3,5
The decision to perform the upper tract intervention wasbased on the patient's elevated creatinine and worsening hydronephrosisin the left (functioning) renal unit. Some decline in the serum creatinineoccurred after percutaneous nephrostomy whether the creatinine would havedecreased further in this child is uncertain. However such prolonged intubateddrainage carriers a real risk of infection and other complications, thusa non-intubated high urinary diversion was performed.
The other confounding consideration is the prematurityof the patient which can influence the outcome of transitional renal development.We felt that this patient had an excellent chance of obtaining normal renalfunction. However if the developing nephrons were subjected to obstructionas was evident with worsening hydronephrosis of the left (functioning)renal unit, renal injury as well as reduced glomerular filtration rate(GFR) would occur. After correction of this urinary obstruction, the prematureinfant's creatinine is expected to decrease as rapidly as a full term baby.3In our past experience in patients with similar nadir creatinines, we feltintervention, as described above, was most appropriate.
In conclusion our case demonstrated that in patients withVURD syndrome, worsening hydronephrosis and/or a persistently elevatedcreatinine may benefit from a high urinary diversion.
References
