Dd is 12 and had hydronephrosis diagnosed antenatally, and a pyeloplasty as a baby. No problems since (discharged from urology clinic aged 6). She had a us scan last week for other issues and it showed severe hydronephrosis again. She had had a scan in summer 2021 which was normal so this has developed in last 18 months. She is now being urgently referred to paediatric urology but I am obvs v concerned. Has anyone had this - a surprise recurring hydronephrosis. What happened?