Posterior Urethral Valves

  • Etiology: anterior fusion of plicae collicularis at level of verumontanum
    — Types – Type I is 95%, Type II doesn’t exist, Type III is 5%
  • VCUG: obstruction by veil-shaped valve leading to dilated posterior urethra, trabeculated thick walled bladder, bilateral hydroureteronephrosis from vesicoureteral reflux -> renal damage so kidneys can be small + echogenic on US
  • Complications: at risk post-operatively for recurrent urinary tract infections due to dilated genitourinary system
  • Clinical: in-utero can have oligohydramnios / urinoma / urine ascites, pulmonary hypoplasia due to oligohydramnios

Radiology Cases of Posterior Urethral Valves

VCUG of posterior urethral valves
AP image from a voiding cystourethrogram (above) shows bilateral grade 5 vesicoureteral reflux, right greater than left, and a narrow pinecone-shaped bladder in the inferior midline aspect of the image. Lateral image of the urethra taken during the voiding phase of the voiding urethrogram (below) shows marked dilation of the posterior urethra and a thin lucent membrane at the transition zone where the urethra assumes a more normal caliber.