Megaureter: classification, pathophysiology, and management

The term megaureter does not define a specific pathological condition, because it can be due to different underlying abnormalities. The most used classification includes three groups: refluxing megaureter, associated with vesicoureteral reflux (VUR); obstructive megaureter, associated with urine flow impairment at the vesicoureteral junction; non-refluxing non-obstructive megaureter, if neither obstruction nor reflux can be identified. Each group can be divided into two subgroups: primary megaureter; secondary megaureter. With the advent of antenatal ultrasound an increased number of cases are identified prior to the onset of symptoms. The common used investigation are: urinary tract ultrasound, voiding cystourethrography, urography, serial diuretic renography and pressure-perfusion studies (Whitaker test). The advent of prenatal and neonatal echography has modified the natural history of megaureter. Nowadays non operative management is preferred. Operative intervention is indicated only in these cases: significant impairment to urine flow; worsening renal function during the observation time; recurrent UTI in spite of adequate antibiotic prophylaxis.