Pelviureteric junction dysfunction in children

Hydronephrosis is often caused by pelviureteric junction dysfunction (PUJD). It is frequently detected during antenatal screening. Common causes of PUJD include intrinsic stenosis and aberrant lower pole vessels. Surgery, usually an Anderson–Hynes type pyeloplasty, is indicated in patients with symptoms such as pain, infection or haematuria. Asymptomatic patients require a baseline MAG3 scan and serial monitoring with ultrasound scanning. Surgery is indicated if there is increasing hydronephrosis with an anterior posterior diameter (APD) >3 cm, function below 40% or a drop in function of >10% on repeat MAG3.