1. CONGENITAL DISORDERS OF THE LOWER URINARY TRACT Pediatric GU Review UCSD Pediatric Urology George Chiang MD Sara Marietti MD Outlined from The Kelalis-King-Belman Textbook of Clinical Pediatric Urology 2007 (not for reproduction, distribution, or sale without consent)
First diagnosed in 1970 with prenatal u/s of polycystic kidney by William Garrett in a 31 week GA fetus Mean age at diagnosis of uropathy is 24 weeks Urine Formation begins at 8 weeks and continues through gestation; by 22 weeks volume of amniotic fluid is maintained by fetal urine production
-Urethral Atresia: complete obstruction caused by a membrane that is located at the distal end of the prostatic urethra -Incompatible with life unless alternative ccommunication develops: patent urachus, vesico-amniotic fistula, fistula to the rectum -Phenotypically similar to prune belly -Sagittal level III ultrasound at 15 weeks of gestation shows classic “keyhole” sign -Combined antegrade via vesicostomy/retrograde urethrogram reveals 2 cm. atretic urethral segment @ 14 months; Subsequently serial dilations and BVUR with later renal transplantation
-2 nd trimester=13 th -27 th weeks -Enlarged Fetal bladder with thickening, Echogenic renal parenchyma, Bilateral hydro and decreased amniotic fluid volume, extrarenal fluid collections such abdominal ascites or perirenal urinoma -Perinephric urinoma associated with echogenic kidneys and posterior urethral valves
-Dr. Hampton Young was creditted for the first clear description and classification of PUV in 1919 -Type I is an obstructing membrane that arises from the posterior and inferior edge of the veru and radiates distally towards the membranous urethra, inserting anteriorly near the proximal margin of the membranous urethra -Type II urethral valves were initially described as folds radiating in a cranial direction from the veru to the posterolateral aspect of the bladder neck; these are not obstructive -Type III valves are incomplete dissolution of the urogenital membrane. The obstructing membranes are situated distally to the veru at the level of the membranous urethra
-Type I valves make up more than 95% of the lesions whereas Type III make up the remainder -During voiding the fused anterior portion of the membrane bulges into the membranous urethra leaving only a narrow opening that is compressed along the posterior wall of the urethra
-Abnormal migration of the terminal ends of the wolffian duct orifices -Normally remains lateral and posterior but abnormal migration places it anteriorly -Disputed theories on development; some suggest they are the remnant of the urogenital membrane
93% are boys, mostly with a history of PUV Leading cause of mortality in obstructive uropathy-Lung development begins at 3-4 weeks and ends near week 24; Reduced external pressure leads to lung fluid being draw freely into amniotic space and therefore reducing the stenting pressure in the lung and impairing normal growth High mortality rate is generally not relfected in postnatal series and represents the “hidden mortality” since these infants do not survive postnatally before transfer to a pediatric specialty center for treatment Late-Onset Oligo >30 weeks not associated with pulmonary insufficiency Fetuses with lower urinary tract obstruction and oligo represent the most severe end of the obstructive uropathy spectrum and are the fetuses one would expect to idenify earliest in gestation and to be the highest risk of pulmonary hypoplasia and renal dysplasis - -
-Bladder dysfunction includes 1)myogenic failure with overflow incontinence 2) Detrusor hyper-reflexia 3) Bladder hypotonia in 31% -Renal Dysfunction: GOS 10 year follow-up: 10% died of RF, 15% ESRD, 6% CRI with progression independent of type of primary surgical treatment Late onset RF metabolic demands of puberty, hyperfiltration injury with decreased functional renal mass , polyuria with impaired urinary concentrating capacity (RF increases with age 6.5% at 5; 25% at 10, 50% at 5. -Decreased libido/potency could be due to CRF and HD; - EJ 48% c/o slow/dry ejaculation and 10/21 patients studied had oligospermia which could be due to failure of dilated posterior urethra to generate enough pressure -Infertility could be associated with cryptorhidism which is in 12% of these patients
Mention speaker at BWH with different incidence Mention speaker at BWH with different incidence m/f almost equal; wilms tumor rate may be higher, no known risk factors ?maternal progestin use
Usually advocate c section because of prolapse issue. LOTS of variation
