Primary megaureter in infants and children
- Laurence S Baskin, MD, FAAP
Laurence S Baskin, MD, FAAP
- Section Editor — Pediatric Urology
- Frank Hinman, Jr., MD, Distinguished Professorship in Pediatric Urology
- Chief Pediatric Urology
- Professor of Urology and Pediatrics
- UCSF Benioff Children's Hospital
Megaureter is defined as a ureter that exceeds the upper limits of normal size. In children, any ureter greater than 7 mm in diameter is considered a megaureter based on measurements in fetuses greater than 30 weeks gestation and children <12 years .
Primary megaureter is a result of a functional or anatomical abnormality involving the ureterovesical junction (figure 1), whereas secondary megaureter results from abnormalities that involve the bladder or urethra (eg, myelomeningocele/neurogenic bladder, and posterior urethral valves).
Primary megaureter in infants and children will be reviewed here.
Primary megaureter is classified according to the presence or absence of reflux and obstruction. Management of primary megaureter depends upon the type of megaureter. (See 'Postnatal management' below.)
The types of megaureter are as follows:
- Cussen LJ. Dimensions of the normal ureter in infancy and childhood. Invest Urol 1967; 5:164.
- Stoll C, Alembik Y, Roth MP, et al. Risk factors in internal urinary system malformations. Pediatr Nephrol 1990; 4:319.
- McLellan DL, Retik AB, Bauer SB, et al. Rate and predictors of spontaneous resolution of prenatally diagnosed primary nonrefluxing megaureter. J Urol 2002; 168:2177.
- Gimpel C, Masioniene L, Djakovic N, et al. Complications and long-term outcome of primary obstructive megaureter in childhood. Pediatr Nephrol 2010; 25:1679.
- Calisti A, Oriolo L, Perrotta ML, et al. The fate of prenatally diagnosed primary nonrefluxing megaureter: do we have reliable predictors for spontaneous resolution? Urology 2008; 72:309.
- Shukla AR, Cooper J, Patel RP, et al. Prenatally detected primary megaureter: a role for extended followup. J Urol 2005; 173:1353.
- Nicotina PA, Romeo C, Arena F, Romeo G. Segmental up-regulation of transforming growth factor-beta in the pathogenesis of primary megaureter. An immunocytochemical study. Br J Urol 1997; 80:946.
- Farrugia MK, Hitchcock R, Radford A, et al. British Association of Paediatric Urologists consensus statement on the management of the primary obstructive megaureter. J Pediatr Urol 2014; 10:26.
- Keating MA, Escala J, Snyder HM 3rd, et al. Changing concepts in management of primary obstructive megaureter. J Urol 1989; 142:636.
- Baskin LS, Zderic SA, Snyder HM, Duckett JW. Primary dilated megaureter: long-term followup. J Urol 1994; 152:618.
- Peters CA, Mandell J, Lebowitz RL, et al. Congenital obstructed megaureters in early infancy: diagnosis and treatment. J Urol 1989; 142:641.
- Link BA, Slobodov G, Campbell JB, Kropp BP. Radiographic changes following excisional tapering and reimplantation of megaureters in childhood: long-term outcome in 46 renal units. J Urol 2007; 178:1474.
- García-Aparicio L, Rodo J, Krauel L, et al. High pressure balloon dilation of the ureterovesical junction--first line approach to treat primary obstructive megaureter? J Urol 2012; 187:1834.
- Liu HY, Dhillon HK, Yeung CK, et al. Clinical outcome and management of prenatally diagnosed primary megaureters. J Urol 1994; 152:614.
- Di Renzo D, Aguiar L, Cascini V, et al. Long-term followup of primary nonrefluxing megaureter. J Urol 2013; 190:1021.
- CLINICAL PRESENTATION
- FURTHER EVALUATION
- DIFFERENTIAL DIAGNOSIS
- PRENATAL MANAGEMENT
- POSTNATAL MANAGEMENT
- Management options
- - Surgery
- - Medical management
- Antibiotic prophylaxis
- Clinical scenario
- - Nonrefluxing megaureter
- Asymptomatic patients
- Symptomatic patients
- - Refluxing megaureter
- Our approach
- - Prenatal presentation
- - Postnatal presentation
- SUMMARY AND RECOMMENDATIONS