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Posterior Urethral Valve (PUV) is a congenital obstructing membranous fold in the posterior urethra (prostatic urethra) in males.

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• Results from abnormal persistence of embryological urogenital membrane.
• It is the most common cause of lower urinary tract obstruction in male infants and children.

https://youtu.be/pOtBGB9xCfo

https://www.youtube.com/watch?v=wk5c8fc1F14

Embryology

![Anterior and lateral diagramatic representation of the prostate, prostatic urethra and internal bladder sphincter in prune belly syndrome (PBS) and PUV as compared to normal. The presence or absence of the internal sphincter is helpful in distinguishing the two syndromes on gross examination or on cystourethrogram.

Popek EJ, Tyson RW, Miller GJ, Caldwell SA. Prostate development in prune-belly syndrome (PBS) and posterior urethral valves (PUV): Etiology of PBS-lower urinary tract obstruction or primary mesenchymal defect? Pediatr Pathol 1991;11:1-29. Raga F, Osborne NG, Bonilla F, Bonilla-Musoles F, Machado LE, Ruiz F, Castillo JC. Prune-belly Syndrome versus Posterior Urethral Valve. Donald School J Ultrasound Obstet Gynecol 2010; 4 (4):405-417.](attachment:1a4de5af-51ee-4d7a-9c43-752807c9a2e0:image.png)

Anterior and lateral diagramatic representation of the prostate, prostatic urethra and internal bladder sphincter in prune belly syndrome (PBS) and PUV as compared to normal. The presence or absence of the internal sphincter is helpful in distinguishing the two syndromes on gross examination or on cystourethrogram.

Popek EJ, Tyson RW, Miller GJ, Caldwell SA. Prostate development in prune-belly syndrome (PBS) and posterior urethral valves (PUV): Etiology of PBS-lower urinary tract obstruction or primary mesenchymal defect? Pediatr Pathol 1991;11:1-29. Raga F, Osborne NG, Bonilla F, Bonilla-Musoles F, Machado LE, Ruiz F, Castillo JC. Prune-belly Syndrome versus Posterior Urethral Valve. Donald School J Ultrasound Obstet Gynecol 2010; 4 (4):405-417.

Epidemiology

• Occurs exclusively in boys.
• Incidence: ~1 in 5,000–8,000 live male births.
• Often diagnosed antenatally (20–30 weeks) due to hydronephrosis and bladder changes.

Pathogenesis

• Abnormal development of Wolffian duct–derived tissue → obstructing leaflets in the posterior urethra.
• Causes high-pressure urinary obstruction → affects bladder, ureters, kidneys.
• Leads to:
  • Hydroureteronephrosis.
  • Bladder dysfunction (“valve bladder” – thick, trabeculated, poorly compliant).
  • Vesicoureteric reflux (VUR)
  • Renal dysplasia (from in utero obstruction).

Clinical Features