Initial observational management of hydronephrosis in infants with reduced differential renal function and non-obstructive drainage parameters

• Published in: Journal of pediatric urology 2022-10, Vol.18 (5), p.661.e1-661.e6
• Main Authors: Hester, Austin G., Krill, Aaron, Shalaby-Rana, Eglal, Rushton, H. Gil
• Format: Article
• Language: English
• Subjects: Differential renal function; Female; Humans; Hydronephrosis; Hydronephrosis - complications; Hydronephrosis - diagnosis; Infant; Infant, Newborn; Kidney - physiology; Kidney Function Tests; Kidney Pelvis - surgery; MAG3 diuretic renal scan; MAG3 lasix scan; Male; Radioisotope Renography - methods; Retrospective Studies; UPJ obstruction; Ureteral Obstruction - complications; Ureteral Obstruction - diagnosis; Ureteral Obstruction - surgery; Ureteropelvic junction obstruction
• ISSN: 1477-5131; 1873-4898
• DOI: 10.1016/j.jpurol.2022.07.023

Hydronephrosis secondary to ureteropelvic junction (UPJ) obstruction is a common finding in infants with prenatally-diagnosed hydronephrosis and often results in pyeloplasty due to obstructive drainage parameters and/or renal function compromise. However, little is known regarding the natural history of hydronephrosis with reduced differential renal function (DRF) but non-obstructive drainage. We sought to explore our experience with initial observational management of these patients. A retrospective review of our institutional database of all diuretic MAG-3 renal scans obtained between 2000 and 2016 was performed. We included patients with antenatally-detected unilateral hydronephrosis ≥ SFU grade 2, first MAG-3 scan prior to 18months of age, DRF 1 MAG3 scan. Of the 7 remaining, 5 were lost to follow-up and 2 demonstrated improvement in hydronephrosis. Worsening drainage occurred in 10/22(45%), median final T1/2 was 45.5 min 8 of these underwent pyeloplasty and 2 were lost to follow up. 4/22 patients (18%) had progressive decline in DRF (mean 8.3%, range 6–10%). 3/4 maintained non-obstructive drainage patterns and stable/improved hydronephrosis, and 1 underwent pyeloplasty. 13/18 remaining patients had stable DRF and 5 had improvement in DRF. 7(39%) of these underwent surgery for worsening drainage (Summary Figure). Overall, 7/29(24%) patients had sufficient resolution of hydronephrosis to be discharged from our care, 8(28%) are under continued observation, 9(31%) underwent pyeloplasty, and 5(17%) were lost to follow-up. In the observational group [median follow-up 4.5 years (3.7-6.6 years)], all 8 demonstrated improved non-obstructive drainage (T1/2