Bilateral Hydronephrosis



Bilateral Hydronephrosis


Sara M. O’Hara, MD, FAAP



DIFFERENTIAL DIAGNOSIS


Common



  • Vesicoureteral Reflux (VUR)


  • Posterior Urethral Valves


  • Neurogenic Bladder


Less Common



  • Megaureter


  • Crossed Fused Ectopia


  • Horseshoe Kidney


  • Megacystis Megaureter


  • Bladder Outlet Obstruction



    • Cecoureterocele


    • Bladder Rhabdomyosarcoma


    • Pelvic Mass with Compression


    • Cloacal and Anorectal Malformations


Rare but Important



  • Prune Belly


  • Urethral Duplication


  • Anterior Urethral Valves


  • Megacalycosis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Some potential diagnoses may occur unilaterally or bilaterally


  • Severe cases typically noted on prenatal imaging and further evaluated in newborn


  • Clinical history and associated anomalies narrow differential


Helpful Clues for Common Diagnoses



  • Vesicoureteral Reflux (VUR)



    • Retrograde flow of urine from bladder toward kidneys


    • Graded from 1 (mild) to 5 (severe)


    • 80% of children outgrow reflux by puberty


    • Associated infection and renal scarring


    • Imaging: Voiding cystourethrography (VCUG), nuclear cystogram, sonocystogram (if US contrast available)


  • Posterior Urethral Valves



    • Congenital condition found only in boys


    • Persistent or prominent plicae colliculi in urethra causes variable degree of obstruction


    • Unilateral VUR or urinoma decompresses system, protective of contralateral kidney



      • Better long-term prognosis


    • Degree of obstruction varies



      • Severe: Usually diagnosed in fetus/newborn with oligohydramnios, respiratory, and renal insufficiency


      • Mild: May go undetected for years; late symptoms include renal failure and bladder dysfunction


    • Imaging: VCUG



      • Shows valve tissue &/or urethral caliber change


    • Treatment: Endoscopic valve ablation


  • Neurogenic Bladder



    • Malfunctioning bladder from any neurologic disorder


    • Upper tract compromised by



      • Poor bladder emptying and VUR


      • Urinary tract infections


      • Elevated bladder pressures


    • Highly compliant bladder in infancy common



      • Huge bladder capacity, poor emptying


    • Gradually develops muscular hypertrophy, which decreases compliance and capacity


    • End stage: Low capacity, noncompliant, noncontractile bladder


    • Imaging: VCUG, US, CT, MR



      • Shows bladder wall trabeculation, VUR, diverticula, capacity, emptying


    • Urodynamics very important to monitor


    • Treatment



      • Medications to improve bladder compliance


      • Catheterization to simulate normal bladder distention and emptying


Helpful Clues for Less Common Diagnoses



  • Megaureter



    • a.k.a. primary megaureter


    • Focal concentric narrowing of extravesical distal ureter 1-3 cm in length


    • Unknown etiology but theorized to be



      • Paucity of ganglion cells or


      • Hypoplasia/atrophy of muscle fibers in distal ureteral segment


    • Refluxing and nonrefluxing varieties


    • Imaging: Diuretic renogram, US, VCUG, MR urography


    • Treatment



      • Resection of narrowed segment and re-implantation


    • Crossed Fused Ectopia



      • Results from abnormal migration of kidney in utero



      • Upper kidney is orthotopic; other kidney is on wrong side and in low position


      • Lower pole of orthotopic kidney fused to upper pole of ectopic kidney


      • Ureter from lower kidney crosses to contralateral trigone


      • Associated aberrant and accessory vessels


      • Hydroureteronephrosis may be segmental or involve whole kidney


      • Imaging: Diuretic renogram, US, VCUG, MR urography


    • Horseshoe Kidney



      • Results from abnormal migration of kidney in utero


      • Lower poles of kidney fused in midline


      • Upper poles are lower than usual


      • Aberrant and accessory vessels and ureters common


      • Hydroureteronephrosis may be segmental or involve whole kidney


      • Imaging: Diuretic renogram, US, VCUG, MR urography


    • Megacystis Megaureter



      • Large, thin-walled, smooth bladder from constant recycling of refluxed urine


      • Bladder contracts normally but never empties completely due to reflux


      • Bladder capacity and function normalize when VUR is corrected


      • Imaging: VCUG


    • Bladder Outlet Obstruction



      • Any cause of bladder outlet obstruction can lead to bilateral hydroureteronephrosis


      • Cecoureterocele



        • Prolapsed ureterocele


      • Bladder Rhabdomyosarcoma



        • Typically large with significant mass effect


      • Pelvic Mass with Compression



        • Sacrococcygeal teratoma, Burkitt, etc.


      • Cloacal and Anorectal Malformations


      • Look for associated genital anomalies, hematometrocolpos


Helpful Clues for Rare Diagnoses

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Aug 10, 2016 | Posted by in PEDIATRICS | Comments Off on Bilateral Hydronephrosis

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