ABSTRACT
Obstruction of the upper urinary tract may be due to congenital anomalies of the ureter at the level of the pelviureteric junction (PUJ) or the vesicoureteric junction (VUJ). Nowadays, most of these cases present with antenatal ultrasound. These two diagnoses contribute to the majority of cases of upper urinary tract obstruction; therefore, discussion of them will be the main focus of this chapter. In addition, in children, there are a few acquired conditions that may cause obstruction of the ureter, either by intraluminal blockage (stones, papillary necrosis) or extraluminal compression (retroperitoneal tumour, intra-abdominal mass). Ureteric strictures in children are unheard of without a history of surgical intervention.
