A posterior urethral valve (PUV) is a membranous fold within the lumen of the posterior urethra that causes functional obstruction of the urine outflow. It is a common cause of obstructive uropathy in boys during the neonatal period. Pathophysiology | Bladder pressure | Wall hyperophy + Collagen deposition | | Compliance Small amounts of urine may cause large increase in bladder pressure | Bilateral Hydronephrosis Reference: GHAI Essential pediatrics, 8th edition