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Journal of Pediatric Surgery (2007) 42, E17–E20

An unusual case of bilateral primitive obstructedmegaureters due to ureteral valves presentingwith anuria at the age of 1 monthPaul Dahera,⁎, Edward Riachyb, Chebel Mouranic, Tarek Smayrad, Soha Haddadd

aDepartment of Pediatric Surgery at Hotel Dieu de France University Hospital–Beirut, LebanonbPediatric Surgery at Hotel Dieu de France University HospitalcPediatric Nephrology at the Department of Pediatric at Hotel Dieu de France University Hospital–Beirut, LebanondDepartment of Radiology at Hotel Dieu de France University hospital–Beirut, Lebanon

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Index words:Primitive obstructedmegaureters;

Ureteral valve;Congenital ureteralstricture

Abstract Ureteric valves represent a very rare etiology of ureteral obstruction. We experienced anunusual case of bilateral distal ureteric valves that presented as bilateral primitive obstructedmegaureters with anuria at the age of 40 days. To our knowledge, this is the second case of bilateralinvolvement of distal ureteric valves reported in the literature. Bilateral ureteral valves should beincluded in the differential diagnosis of bladder outlet obstruction, as well as bilateral primitiveobstructed megaureters in children. Excision and ureteral reimplantation is curative.© 2007 Published by Elsevier Inc.

Ureteric valves represent a very rare etiology of ureteralobstruction. We experienced an unusual case of bilateraldistal ureteric valves that presented as bilateral primitiveobstructed megaureters with anuria at the age of 40 days.This is the second case of bilateral involvement of distalureteric valves, the first being reported in 1952 by Wall andWachter [1].

⁎ Corresponding author. Department of Pediatric Surgery, Hôtel Dieue France Hospital, Boulevard Alfred Naccache, Achrafieh, PO Box:6-6830, Beirut, Lebanon. Tel.: +961 3 324577, +961 1 615300x3150;x: +961 1 615300x7323.E-mail addresses: jmpaul@dm.net.lb (P. Daher),

ddy_riachy@msn.com (E. Riachy).

022-3468/$ – see front matter © 2007 Published by Elsevier Inc.oi:10.1016/j.jpedsurg.2007.08.047

1. Case presentation

This is a 40-day-old newborn male that was referred to usfor complete anuria and acute renal failure.

His story began 1 week before, when he presentedunexplained crying, irritability, and vomiting. A blood testrevealed acute renal failure (creatinin = 435 μmol/L, urea =17.8 mmol/L, Na+ = 121 mEq/L, K+ = 6.7 mEq/l, Cl− = 93mEq/L, HCO3

− = 7 mEq/L). A Foley catheter revealed nourine in the bladder. Ultrasound showed hugely dilatedbilateral renal pelvis and ureters, ascites, right pleuraleffusion, and an empty bladder. A review of his historywith his parents revealed no evidence of pathologic antenataldiagnosis on ultrasound, a normal delivery, and a normalurinary flow before this episode. At the emergency room, thepatient was pale, hypotonic, and irritable. Abdomen wasdistended, with no palpable mass.

Fig. 1 Bilateral antegrade percutaneous pyelography demonstrat-ing megaureters and distal ureteral obstruction, followed bynarrower ureters entering the bladder (arrows).

Fig. 2 Cystoscopy demonstrating normal ureteric orifice.Catheterization was possible for a few centimeters before collidingto the obstruction.

Fig. 3 Operative view of the bilateral megaureters and the distallocalization of the ureteral valves. Note the ureters beingcatheterized for a few centimeters, before colliding with the ureteralvalves (at the level of the white arrows).

E18 P. Daher et al.

Our primary diagnosis was that of a posterior urethralvalve (PUV) with bladder rupture, explaining the ascites.However, a voiding cystourethrogram (VCUG) showed anormal micturition pattern of the urethra, ruling out thediagnosis of PUV.

Because of the instability of the patient, we decidedto perform an urgent bilateral percutaneous nephrostomyunder local anesthesia in the neonatal intensive care unit.The patient's renal function dramatically restored within24 hours.

Four days later, a bilateral antegrade pyelography wasperformed from the nephrostomy tubes and showed bilateraldistal ureteric obstruction extending 35 mm beyond thebladder (Fig. 1).

An excision with ureteral reimplantation was planned aweek later. In the meantime, the patient's bladder wasprogressively dilated on a daily basis by filling it withphysiologic serum from the Foley catheter. On theoperative day, cystoscopy revealed 2 normal uretericorifices that were easily catheterizable for a few centi-meters before colliding to the stenosis bilaterally (Fig. 2).A bilateral ureteral reimplantation (Cohen procedure) withureteral remodeling and tapering according to Kalicinskiwas therefore performed. The ureteral dissection showed amegaureter, followed by a short ureteral conduit, andseparated by a ureteral diaphragm with a pinpoint openingbilaterally (Fig. 3).

Histopathology revealed a true annular valve composedof ureteral mucosa and smooth muscle hypertrophy at itsbase (Fig. 4).

2. Discussion

It is agreed that the cause of primary obstructivemegaureter is an adynamic juxtavesical ureteral segment

Fig. 4 Histologic examination reveals a normal ureter (A) preceded by a true annular valve (B) composed of ureteral mucosa (M) andsmooth muscle (SM) hypertrophy at its base. Hematoxylin and eosin, original magnification ×100.

E19An unusual case of bilateral primitive obstructed megaureters

that is unable to propagate urine with resulting functionalobstruction that is never total.

Congenital ureteral valves are a rare cause of ureteralobstruction. We have found only 60 cases of ureteric valvesreported in the peer-reviewed literature [1-8]. They were firstdescribed by Wolfler [2] in 1877 in newborn and fetalautopsies. In 1952, Wall and Wachter [1] proposed thefollowing criteria for the diagnosis of ureteral valves: (1)presence of transverse folds of the ureteral mucosa contain-ing bundles of smooth muscle fiber on histologic examina-tion, (2) signs of obstructive disease above the valve with anormal ureter below it, and (3) no other evidence ofmechanical or functional obstruction.

Rabinowitz [3] suggested that it would be more logical tosimply categorize valves as type I or type II, with type Ihaving smooth muscle present within the leaflet and type IIhaving smooth muscle at the base only.

The types of valves reported have been both cusp-like(leaflet) and diaphragmatic or annular in both the adult andpediatric populations [3]. According to Wall and Wachter [1]and Rabinowitz [3], our case is an annular (diaphragmatic)type I true ureteral valve, as demonstrated by histopathology.

The distribution of valves within the ureter in children isreported as follows: 50% occur in the proximal ureter, 17%in mid ureter, and 33% in the distal ureter. One case ofmultiple valves on the same side has also been described [8].Bilateral involvement is exceedingly rare, and has been onlydescribed once in the literature by Wall and Wachter in 1952[1] in an autopsy of a 5-month-old male that initiallypresented with bilateral obstructed and refluxing megaureterand urinary tract infection at the age of 1 week. Thus, thecase we report is the second case of bilateral primitiveobstructed megaureters. However, it should be noted that the

modes of presentation are slightly different: our case had alater age of presentation (40 days) while being totallyasymptomatic before; he had no reflux on VCUG andinitially presented with complete anuria as demonstrated byabsence of urine on catheterization. Still, both cases weresuspected to be a bladder outlet obstruction (PUV) duringtheir initial evaluation.

Half of the patients with ureteral valves also haveassociated urinary anomalies, including ureteral duplication,reflux, ectopic ureter, and contralateral hypoplastic kidneyor renal agenesis [3]. Fortunately, our patient had noassociated anomalies.

The embryogenesis of ureteral valves remains unclear.Two major theories presently exist: the persistence ofChwalle's membrane and physiologic folds.

The persistence of Chwalle's membrane might explain thepresence of lower ureteral valves [1]. Chwalle's membrane isan epithelial membrane in the lower portion of the ureterallumen and is a normal feature of ureteral development at 6weeks of gestation. During the eighth week of gestation,Chwalle postulated rupture of that membrane and theestablishment of ureteral patency under the pressure ofurine excretion. Partial rather than complete rupture of themembrane may result in a retained membrane that wouldconstitute a ureteral valve. However, this theory does notexplain multiple valves in one ureter or valves proximal tothe ureterovesical junction [4,5].

At the 5th week of embryologic life, the ureteral budoriginating from the mesonephric (Wolfian) duct growstowards the metanephric blastema. On the other hand, themetanephros undergoes an ascent towards its definitivelocation. If the ureteral growth is faster than the renalmigration, then a “ureteral fold” would form. Ureteral valves

E20 P. Daher et al.

are the persistence of exaggerated and obstructive fetalphysiologic ureteral folds. This theory seems more compa-tible with multiple valves in one ureter [4,6,7].

We cannot conclude which theory is to be adoptedbecause both can explain a bilateral involvement in thedistal ureter.

The ureteral valves must be differentiated fromcongenital ureteral strictures, which are rare, usuallyfound in early adulthood, but can be often revealed byhydronephrosis on antenatal ultrasound [9,10]. Theycorrespond to a segmental ureteral fibrosis, usuallyassociated to a smooth muscle hypoplasia. The ureterallumen is usually narrow but sometimes can be of normalcaliber. The stricture can be localized anywhere in theureter [10]. Muscularization of the ureteral tube begins atthe 12th week of gestation and continues throughoutpregnancy. The pathophysiology of these lesions may bedue to a vascular compression that might interfere with themuscularization process, leading to an incompletely formedsegment of ureteral mucosa [10-12]. These vessels,however, are not always demonstrable; it is postulatedthat they disappear as part of the embryological develop-mental process, leaving behind the stricture [12]. As far aswe know, no case of bilateral congenital ureteral strictureshas been described in the literature.

Treatment of ureteral valve depends on its location andthe severity of renal injury and includes pyelolureterostomy,primary ureteroureterostomy, or excision of leaflet andureteral reimplantation in case of distal involvement [3].Endoscopic incision is also thought to be a useful treatmentfor the ureteric valve [8].

3. Conclusion

Congenital ureteric valves represent a very rare etiologyof primary ureteral obstruction, but they do exist. They

should be differentiated from congenital ureteral strictures.Bilateral involvement, although unusual, should be includedin the differential diagnosis of bladder outlet obstruction, aswell as bilateral primitive obstructed megaureters in children.This former entity, even in bilateral involvement, is notusually associated with complete anuria. The diagnosis ismade on retrograde pyelography or antegrade pyelography incase of available percutaneous nephrostomy. The VCUG isuseful to rule out vesicoureteric reflux (VUR), as well as toscreen for other associated urinary abnormalities. Excisionand ureteral tapering reimplantation is curative.

References

[1] Wall B, Wachter E. Congenital ureteral valve: its role as a primaryobstructive lesion: classification of the literature and report of anauthentic case. J Urol 1952;68:684-90.

[2] Wolfler A. Neue Beitrage zur chirurgischen pathologie der Nieren.Arch Klin Chir 1877;21:694-723.

[3] Rabinowitz R, Kingston TE, Wesselhoeft C, et al. Ureteral valves inchildren. Urology 1998;51:7-11.

[4] Schoepen Y, Poli-Merol ML, Belouadah M, et al. Ureteral valves:report of 3 cases. Prog Urol 2003;13:470-6.

[5] Maizels M, Stephens FD. Valves of the ureter as a cause of primaryobstruction of the ureter: anatomic, embryologic and clinical aspects.J Urol 1980;123:742-7.

[6] Mering JH, Steel JF, Gittes RF. Congenital ureteral valves. J Urol1972;107:737-9.

[7] Sant GR, Barbalias GA, Klauber GT. Congenital ureteral valves—anabnormality of ureteral embryogenesis? J Urol 1985;133:427-31.

[8] Nishio S, Hamada H, Yokoyama M. Endoscopic incision for thetreatment of a ureteric valve. BJU Int 1999;83:1081-2.

[9] Gitlin J, Kaefer M. Congenital mid ureteral strictures presenting asprenatal hydronephrosis. J Urol 2002;168:1154-5.

[10] Hwang AH, McAleer IM, Shapiro E, et al. Congenital mid ureteralstrictures. J Urol 2005;174:1999-2002.

[11] Cauchi JA, Chandran H. Congenital ureteric strictures: an uncommoncause of antenatally detected hydronephrosis. Pediatr Surg Int 2005;21:566-8.

[12] Allen T. Congenital ureteral strictures. J Urol 1970;104:196.