Development of renal function after neonatal urinary ascites due to obstructive uropathy

Neonatal urinary ascites is a rare complication of obstructive uropathy with possible lethal outcome if not treated adequately. We demonstrate that with adequate therapy the survival rate can be high and long-term survival, kidney function and lower urinary tract function of patients with urinary ascites can be good.

The study included 4 females and 8 males born with urinary ascites. Followup ranged from 3 to 14 years. Blood analysis for renal function, electrolytes and blood gas was performed at hospitalization and during followup. Ultrasound, cystourethrograms or cystoscopy showed the site of obstruction and leakage of urine. All patients were initially treated with drainage of the ascites and decompression of the obstructed urinary tract. All patients underwent surgery to remove the obstruction and reconstruct the urinary tract. Bladder and kidney function was evaluated at long-term followup.

All patients had severe abdominal distention at presentation. Severe metabolic acidosis was present in cases that had not been detected prenatally or immediately after birth. Two patients died of causes related to pulmonary hypoplasia. Surprisingly urinary continence and renal function were good in 9 of 10 survivors.

Long-term outcome of bladder and kidney function is surprisingly good in cases of severe obstructive uropathy with ascites. Intrauterine pressure relief of the bladder through urinary extravasation protects renal function and this decompression of the urinary tract prevents severe secondary changes to bladder function. Although not proven we believe that high intrauterine pressures in the abdominal cavity are prevented by peritoneal absorption of the extravasated urine and consequent dialysis through the placenta.