Clinical Significance (Posterior Urethral Valves)

mikt_1a_n.jpg and mikt_1b_n.jpg: In this preparation of a 9-month-old boy who died from renal insufficiency, the kidneys, ureters, bladder, and urethra are visible. They are used to illustrate the clinical significance of posterior urethral valves. mikt_1a_n.jpg: Close-up picture: The bladder wall is thick. Two folds are visible which originate from the colliculus. The left-sided fold continues in a swallow's nest-like sail. The only partially depicted posterior urethral valves are an obstruction for voiding the bladder and lead clinically to differently severe voiding disorders and pathoanatomically to secondary changes of the bladder wall, such as hyperthrophy of the bladder wall, pseudo-diverticula of the bladder, and later to disturbances of bladder function. mikt_1b_n.jpg: Overview: The ureters are wide and tortuous. The right kidney is small and consists only of a dilated pelvis except for some residual parenchyma on the upper pole. The normal sized left kidney has a dilated pelvis. In severe types of posterior urethral valves there is also a primary and/or secondary involvement of the kidneys, such as dysplasia and damage by obstruction, and reflux of the upper urinary tract. Due to the secondary changes of the bladder wall, a secondary obstructive megaureter and a secondary vesicoureteral reflux may be present, the latter due to an extravesicalization of the orifices by the pseudo-diverticula.