Primary non-refluxing megaureter: Natural history, follow-up and treatment

Abstract

Primary non-refluxing megaureter (PMU) is a congenital dilation of the ureter which is not related to vesicoureteral reflux, duplicated collecting systems, ureterocele, ectopic ureter, or posterior urethral valves and accounts for 5 to 10% of all prenatal hydronephrosis (HN) cases. The etiology is a dysfunction or stenosis of the distal ureter. Most often PMU remains asymptomatic with spontaneous resolution allowing for non-operative management. Nevertheless, in selective cases such as the development of febrile urinary tract infections, worsening of the ureteral dilatation, or reduction in relative renal function, surgery should be considered.

Conclusion: Ureteral replantation with excision of the dysfunctional ureteral segment and often ureteral tapering is the gold-standard procedure for PMU, although endoscopic treatment has been shown to have a fair success rate in many studies. In this review, we discuss the natural history, follow-up, and treatment of PMU.

What is known: • PMU is the result of an atonic or stenotic segment of the distal ureter, resulting in congenital dilation of the ureter, and is frequently diagnosed on routine antenatal ultrasound.

What is new: • Most often, PMU remains asymptomatic and clinically stable, allowing for non-operative management. • Nevertheless, since symptoms can appear even after years of observation, long-term ultrasound follow-up is recommended, even up to young adulthood, if hydroureteronephrosis persists. • Ureteral replantation is the gold standard in case surgery is needed. In selected cases, however, HPBD could be a reasonable alternative.

Keywords: Continuous antibiotic prophylaxis; High-pressure balloon dilation; Primary non-refluxing megaureter; Ureteral replantation; Urinary tract infections.

Fig. 1

Follow-up flowchart for PMU. US, ultrasound; VCUG, voiding cystourethrogram; Tc99m Mag3, mercaptuacetyltriglycine