4 types classified by presence of vesicoureteral reflux (VUR) &/or obstruction
Nonrefluxing obstructed (NR, O)
Refluxing obstructed (R, O)
Refluxing nonobstructed (R, NO)
Nonrefluxing nonobstructed (NR, NO)
Primary obstructive megaureter: Congenital functional obstruction at juxtavesical segment of ureter
Presumably due to absent peristalsis in normal-caliber distal segment, though exact etiology is unclear
IMAGING
General Features
Radiographic Findings
Ultrasonographic Findings
Fluoroscopic Findings
Nuclear Medicine Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Microscopic Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
Selected References
Torino G et al: High-pressure balloon dilatation for the treatment of primary obstructive megaureter: is it the first line of treatment in children and infants? Swiss Med Wkly. 151:w20513, 2021
Dekirmendjian A et al: Primary non-refluxing megaureter: analysis of risk factors for spontaneous resolution and surgical intervention. Front Pediatr. 7:126, 2019
Teklali Y et al: Endoscopic management of primary obstructive megaureter in pediatrics. J Pediatr Urol. 14(5):382-7, 2018
Babu R: 'Mini reimplantation' for the management of primary obstructed megaureter. J Pediatr Urol. 12(2):103.e1-4, 2016
Emad-Eldin S et al: Diagnostic value of combined static-excretory MR Urography in children with hydronephrosis. J Adv Res. 6(2):145-53, 2015
Kart Y et al: Altered expression of interstitial cells of Cajal in primary obstructive megaureter. J Pediatr Urol. 9(6 Pt B):1028-31, 2013
Wildbrett P et al: Impact of magnetic resonance urography and ultrasonography on diagnosis and management of hydronephrosis and megaureter in paediatric patients. Afr J Paediatr Surg. 9(2):122-7, 2012
Gimpel C et al: Complications and long-term outcome of primary obstructive megaureter in childhood. Pediatr Nephrol. 25(9):1679-86, 2010
Hodges SJ et al: Megaureter. ScientificWorldJournal. 10:603-12, 2010
Khrichenko D et al: Functional analysis in MR urography - made simple. Pediatr Radiol. 40(2):182-99, 2010
Neulander EZ et al: Upper pole multicystic dysplasia and ureteropelvic junction obstruction associated with obstructive-refluxing megaureter in a neonate with a single kidney. Can J Urol. 17(6):5472-4, 2010
Vlad M et al: Morphological study of congenital megaureter. Rom J Morphol Embryol. 48(4):381-90, 2007
Kocaoglu M et al: Intravenous contrast-enhanced dynamic MR urography: diagnosis of vesicoureteral reflux during bladder filling with time-signal intensity curves. J Magn Reson Imaging. 24(2):349-55, 2006
Merlini E et al: Primary non-refluxing megaureters. J Pediatr Urol. 1(6):409-17, 2005
Shukla AR et al: Prenatally detected primary megaureter: a role for extended followup. J Urol. 173(4):1353-6, 2005
McLellan DL et al: Rate and predictors of spontaneous resolution of prenatally diagnosed primary nonrefluxing megaureter. J Urol. 168(5):2177-80; discussion 2180, 2002
Shokeir AA et al: Primary megaureter: current trends in diagnosis and treatment. BJU Int. 86(7):861-8, 2000
Simoni F et al: Megaureter: classification, pathophysiology, and management. Pediatr Med Chir. 22(1):15-24, 2000
Meyer JS et al: Primary megaureter in infants and children: a review. Urol Radiol. 14(4):296-305, 1992
Blickman JG et al: The coexistence of primary megaureter and reflux. AJR Am J Roentgenol. 143(5):1053-7, 1984
UpToDate: Primary megaureter in infants and children. Published July 2, 2019. Reviewed July 2021. Accessed July 26, 2021. http://www.uptodate.com/contents/primary-megaureter-in-infants-and-children
Orphanet: Congenital primary megaureter . Published May 2010. Accessed July 26, 2021. http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=617
RSNA RadioGraphics: Pediatric MR Urography: Indications, Techniques, and Approach to Review. Published July 14, 2015. Accessed July 26, 2021. http://dx.doi.org/10.1148/rg.2015140223
Related Anatomy
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Related Differential Diagnoses
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References
Tables
Tables
KEY FACTS
Terminology
Imaging
Clinical Issues
TERMINOLOGY
Synonyms
Congenital megaureter, ureteral achalasia
Definitions
Megaureter: Ureteral diameter ≥ 7 mm
4 types classified by presence of vesicoureteral reflux (VUR) &/or obstruction
Nonrefluxing obstructed (NR, O)
Refluxing obstructed (R, O)
Refluxing nonobstructed (R, NO)
Nonrefluxing nonobstructed (NR, NO)
Primary obstructive megaureter: Congenital functional obstruction at juxtavesical segment of ureter
Presumably due to absent peristalsis in normal-caliber distal segment, though exact etiology is unclear
IMAGING
General Features
Radiographic Findings
Ultrasonographic Findings
Fluoroscopic Findings
Nuclear Medicine Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Microscopic Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
Selected References
Torino G et al: High-pressure balloon dilatation for the treatment of primary obstructive megaureter: is it the first line of treatment in children and infants? Swiss Med Wkly. 151:w20513, 2021
Dekirmendjian A et al: Primary non-refluxing megaureter: analysis of risk factors for spontaneous resolution and surgical intervention. Front Pediatr. 7:126, 2019
Teklali Y et al: Endoscopic management of primary obstructive megaureter in pediatrics. J Pediatr Urol. 14(5):382-7, 2018
Babu R: 'Mini reimplantation' for the management of primary obstructed megaureter. J Pediatr Urol. 12(2):103.e1-4, 2016
Emad-Eldin S et al: Diagnostic value of combined static-excretory MR Urography in children with hydronephrosis. J Adv Res. 6(2):145-53, 2015
Kart Y et al: Altered expression of interstitial cells of Cajal in primary obstructive megaureter. J Pediatr Urol. 9(6 Pt B):1028-31, 2013
Wildbrett P et al: Impact of magnetic resonance urography and ultrasonography on diagnosis and management of hydronephrosis and megaureter in paediatric patients. Afr J Paediatr Surg. 9(2):122-7, 2012
Gimpel C et al: Complications and long-term outcome of primary obstructive megaureter in childhood. Pediatr Nephrol. 25(9):1679-86, 2010
Hodges SJ et al: Megaureter. ScientificWorldJournal. 10:603-12, 2010
Khrichenko D et al: Functional analysis in MR urography - made simple. Pediatr Radiol. 40(2):182-99, 2010
Neulander EZ et al: Upper pole multicystic dysplasia and ureteropelvic junction obstruction associated with obstructive-refluxing megaureter in a neonate with a single kidney. Can J Urol. 17(6):5472-4, 2010
Vlad M et al: Morphological study of congenital megaureter. Rom J Morphol Embryol. 48(4):381-90, 2007
Kocaoglu M et al: Intravenous contrast-enhanced dynamic MR urography: diagnosis of vesicoureteral reflux during bladder filling with time-signal intensity curves. J Magn Reson Imaging. 24(2):349-55, 2006
Merlini E et al: Primary non-refluxing megaureters. J Pediatr Urol. 1(6):409-17, 2005
Shukla AR et al: Prenatally detected primary megaureter: a role for extended followup. J Urol. 173(4):1353-6, 2005
McLellan DL et al: Rate and predictors of spontaneous resolution of prenatally diagnosed primary nonrefluxing megaureter. J Urol. 168(5):2177-80; discussion 2180, 2002
Shokeir AA et al: Primary megaureter: current trends in diagnosis and treatment. BJU Int. 86(7):861-8, 2000
Simoni F et al: Megaureter: classification, pathophysiology, and management. Pediatr Med Chir. 22(1):15-24, 2000
Meyer JS et al: Primary megaureter in infants and children: a review. Urol Radiol. 14(4):296-305, 1992
Blickman JG et al: The coexistence of primary megaureter and reflux. AJR Am J Roentgenol. 143(5):1053-7, 1984
UpToDate: Primary megaureter in infants and children. Published July 2, 2019. Reviewed July 2021. Accessed July 26, 2021. http://www.uptodate.com/contents/primary-megaureter-in-infants-and-children
Orphanet: Congenital primary megaureter . Published May 2010. Accessed July 26, 2021. http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=617
RSNA RadioGraphics: Pediatric MR Urography: Indications, Techniques, and Approach to Review. Published July 14, 2015. Accessed July 26, 2021. http://dx.doi.org/10.1148/rg.2015140223
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