138
Bladder Anomalies in Children
Dominic Frimberger; Bradley P. Kropp
Questions
1.At which point in time is fetal urine production sufficient so that at least 50% of bladders can be detected by ultrasound?
a.8 weeks
b.10 weeks
c.12 weeks
d.14 weeks
e.16 weeks
2.How can obstructive and nonobstructive bladder dilatation be distinguished on prenatal ultrasound?
a.Thickness of the bladder
b.Degree of ureteral dilation
c.Presence of oligohydramnios
d.Dilated bladder neck
e.Size of the bladder
3.How is the presence of vesicoureteral reflux in congenital megacystis explained?
a.High-pressure bladder
b.Ectopic insertion of the ureteral orifice into the trigone
c.Bladder dilation from continuous recycling of refluxing urine
d.Obstruction of the bladder outlet
e.High urine output
4.Which of the following is NOT considered a urachal anomaly?
a.Patent urachus
b.Umbilical-urachus sinus
c.Urachal cyst
d.Vesicourachal diverticulum
e.Urethral-urachus fistula
5.Which other embryologic remnant must be differentiated from a patent urachus?
a.Patent omphalomesenteric duct
b.Choledochal cyst
c.Meckel diverticulum
d.Ureteral duplication
e.Congenital bladder diverticulum
6.Which of the following congenital syndromes are NOT associated with bladder diverticula?
a.Ehlers-Danlos
b.Elfin facies
c.Menkes syndrome
d.Sutcliffe-Sandifer syndrome
e.c and d
7.Which theories explain the development of duplicated bladders?
a.Complete duplication of the bladder and hindgut is thought to occur due to partial twinning of the tail portion of the embryo.
b.The development of a sagittal fissure on the cloacal plate occurs when the urorectal septum separates the urogenital from the digestive sinus.
c.Failure of the lateral mesenchymal tissue to migrate
d.Early rupture of the cloacal membrane
e.a and b
Answers
1.b. 10 weeks. The bladder can be visualized in approximately 50% of cases in the fetal pelvis at the tenth week of gestation, concurrent with the onset of urine production (Green and Hobbins, 1998).* The detection rate increases with fetal age to 78% at 11 weeks, 88% at 12 weeks, and almost 100% at 13 weeks.
2.c. Presence of oligohydramnios. It is very difficult to distinguish in utero whether the dilatation is due to obstruction or not. Obstructed cases present with moderate to severe oligohydramnios and a marked increase in renal echogenicity, whereas nonobstructed bladders tend to have normal amniotic fluid levels and regular renal echogenicity (Kaefer et al, 1997).
3.c. Bladder dilation from continuous recycling of refluxing urine. The observed reflux is not an after effect of obstruction, but rather the cause of the bladder dilatation from continuous recycling of the urine between the upper tract and bladder.
4.e. Urethral-urachus fistula. Four different urachal anomalies have been described: patent urachus, umbilical-urachus sinus, urachal cyst, and vesicourachal diverticulum. There is no such thing as a urethral-urachus fistula.
5.a. Patent omphalomesenteric duct.
6.d. Sutcliffe-Sandifer syndrome. Congenital diverticula are often found in children with generalized connective tissue diseases such as EhlersDanlos, elfin facies, or Menkes syndrome (Levard et al, 1989; Rabbitt et al, 1979; Daly and Rabinovitch, 1981). Sutcliffe-Sandifer syndrome is associated with gastroesophageal reflux.
7.e. a and b. Complete duplication of the bladder and hindgut is thought to occur due to partial twinning of the tail portion of the embryo (Ravitch and Scott, 1953). It also is suggested that the development of a sagittal fissure on the cloacal plate occurs when the urorectal septum separates the urogenital from the digestive sinus (Bellagha et al, 1993).
Chapter review
1.The fetal bladder empties every 15 to 20 minutes, so if it is not visualized, repeat ultrasound 15 to 20 minutes later should be performed.
2.When obstruction is the cause of a dilated bladder in the fetus, the mother usually has oligohydramnios.
3.Congenital megacystis is defined as a dilated, thin-walled bladder with a wide and poorly developed trigone. These bladders generally have widegaping ureteral orifices that are displaced laterally, causing massive reflux. Correcting the reflux often restores normal voiding dynamics.
4.Urachal remnants often undergo spontaneous resolution if discovered in patients younger than 6 months. An infected urachal remnant should be initially drained and treated with antibiotics; once the infection has subsided, an excision should be performed.
5.A urachal sinus must be differentiated from a persistent omphalomesenteric duct. The latter presents as a Meckel diverticulum connected to the umbilicus.
6.Urachal cysts do not communicate with either the bladder or umbilicus.
7.Portions of a bladder can be contained within a hernia sac.
8.Dilation of the fetal bladder due to obstruction is usually secondary to a urethral stricture, urethral valves, or urethral atresia. Extrinsic masses may also obstruct the bladder outlet.
9.Nonobstructed bladder dilation may be seen in prune-belly syndrome and neurogenic bladder.
10.Patients with bladder duplication often have associated genital anomalies and may have gastrointestinal anomalies.
11.Four different urachal anomalies have been described: patent urachus, umbilical-urachus sinus, urachal cyst, and vesicourachal diverticulum.
12.Congenital bladder diverticula are often found in children with generalized connective tissue diseases.
* Sources referenced can be found in Campbell-Walsh Urology, 11th Edition, on the Expert Consult website.