Upper urinary tract obstruction

Abstract Upper urinary tract obstruction, secondary to pelvi-ureteric (PUJ) or vesico-ureteric junction (VUJ) obstruction, is common, with a significant number of cases being detected antenatally. The degree of hydronephrosis is described by recording the anteroposterior renal pelvis diameter (RPD). Postnatal investigations are recommended if the RPD is >7 mm. In PUJ obstruction, pyeloplasty is indicated for symptoms or for asymptomatic children with an RPD of >35 mm. Close follow-up of children with an RPD of 20–35 mm is required, as a proportion will progress and need pyeloplasty. In VUJ obstruction, surgery is indicated in children with symptoms or with a distal ureteric diameter of >15 mm.