Further predictors of renal dysplasia in fetal obstructive uropathy: Bladder pressure and biochemistry of ‘fresh’ urine

Abstract

Urine was aspirated on two consecutive days from the dilated bladder of nine fetuses with lower urinary tract obstruction. Gestational age ranged from 17 to 35 weeks. Renal dysplasia was diagnosed histologically in four fetuses, whereas the other five had normal renal histology or only partial dysplasia. Urinary sodium (Na+) and osmolality (Osm) decreased significantly in the second urine sample 1 day after bladder emptying (median decrease: Na+ = -11.3 per cent; Osm = -13.3 per cent). Although there were no significant differences between fetuses with or without renal dysplasia, normalization of an initially raised urine Na+ concentration occurred at the second sample in a fetus with partially normal renal histology, thus correcting a false-positive diagnosis of dysplasia. Bladder pressure was measured at the time of the first urine sampling in seven fetuses and in a further eight with bladder outlet obstruction undergoing a single urine aspiration at 18-28 weeks. Bladder pressure was increased above the reference range in 8 of 15 fetuses with urinary obstruction, but there was no correlation between pressure and the degree of impairment of renal function. Although no conclusive clinical guidelines can be drawn from this study for the evaluation of fetal renal function, these findings suggest that, in lower urinary tract obstruction, tubular reabsorption is impeded by the standing pressure in the urinary tract and that improvement of renal function may occur following relief of obstruction.

Outcomes of fetuses with lower urinary tract obstruction treated with vesicoamniotic shunt: A single-institution experience

“…Ten patients (71%) had at least one VAS. When compared to similar previous studies, where 46%-56% of patients had shunts placed, we had a significantly higher percentage of patients that underwent VAS [9,[19][20][21]. This likely reflects the increasing popularity of the technique over the past decade and specific intervention-based referral patterns for our center.…”

“…In the present study we identified 14 patients prenatally diagnosed with LUTO over an 8-year period, all of whom were male with normal karyotypes and variable ultrasound features classic for the condition [9,[16][17][18][19][20][21]. Ten patients (71%) had at least one VAS.…”

In utero Fetal Urine Analysis and Renal Histology Correlate with the Outcome in Fetal Obstructive Uropathies

“…They attributed the differences in morpholo gy primarily to ectopic origins of the ureteric bud from the wolffian duct. Nicolini et al [ 12] reached a similar conclusion and pointed out that renal dysplasia might be an association rather than a consequence of obstruction.…”

Fetal therapy for obstructive uropathy: past, present.....future?

“…Nicolini et al [34] were the first to suggest that predictive accuracy may be improved by a second vesicocentesis in order to obtain "fresh" urine after the initial bladder drainage. Johnson et al [35] later expanded this to a series of three sequential fetal bladder aspirations, each 48 h apart.…”