[Neonatal ascites caused by urine leakage].

Two neonates, born with an extremely distended abdomen due to ascites, are described. A leakage of urine, secondary to urinary tract obstruction by urethral valves, was the cause of peritoneal fluid accumulation. Analysis of the peritoneal fluid is an important step in differential diagnosis, because only in ascites of urinary origin the creatinine- and ureaconcentrations exceed those of plasma. Treatment consists of temporary urinary diversion followed by operative relief of the obstruction.