Editing Pediatrics: Bladder Anomalies (section)

=== Dilated fetal bladder ===
* '''Due to obstruction or caused by incomplete emptying of the bladder without evidence of a mechanical obstruction; difficult to distinguish in utero if the dilation is due to obstruction'''
* '''Commonly associated with severe anomalies, often the cause for oligohydramnios, and can require fetal or immediate postnatal intervention to prevent fetal demise'''
* Determination of the sex of the child is very important because of the male gender predominance of certain conditions and diseases such as posterior urethral valves or prune belly syndrome.
* '''Dilation Caused by Anatomic Obstruction'''
** '''Mostly due to urethral anomalies or external obstruction'''
*** '''Urethral anomalies include congenital urethral strictures, anterior and posterior urethral valves, and urethral atresia'''
*** '''Compression of the bladder outlet region can be due to obstructing syringoceles, a sacrococcygeal teratoma or pelvic neuroblastoma, an anterior sacral myelomeningocele, or rectum anomalies.'''
* '''Dilation in Non-obstruction'''
** '''Fetuses with nonobstructive dilation appear to pass enough urine to maintain renal function and adequate amniotic fluid levels throughout the pregnancy'''
** '''Prune Belly Syndrome and Neurogenic Bladder Disease'''
*** Affected patients do not demonstrate any sign of obstruction on postnatally performed voiding studies or cystoscopic evaluations, except when urethral atresia is also present
* '''Congenital Megacystis'''
** '''The term megacystis is often used to describe any condition leading to a distended fetal bladder in utero'''
** Bladder dilation is from the continuous recycling of the urine between the upper tract and bladder
** '''Bladder contractility is normal, although a majority of the urine refluxes into the ureters with each void. No neurogenic abnormalities are described.'''
** Most patients are recognized prenatally and should be placed on prophylactic antibiotics after birth.
** '''Correcting the reflux often restores normal voiding dynamics and should be performed after 6 months of age.''' Reduction cystoplasty can be performed but is usually unnecessary
** Congenital megacystis has been recognized in association with microcolon-intestinal hypoperistalsis syndrome. This syndrome is a rare congenital disorder characterized by a dilated, nonobstructive urinary bladder and hypoperistalsis of the gastrointestinal (GI) tract. The syndrome can be identified on antenatal ultrasound by the appearance of a largely dilated bladder. It has been reported mostly in females and is usually considered lethal