Perinatal rupture of the uropoietic system

Ruptures of the uropoietic system resulting in either urinary ascites or urinoma are rare complications in the neonate. Although ruptures without clear predisposing factors are described, in most cases they are associated with obstructive uropathy. The diagnosis is often delayed and the prognosis is related to the degree of renal damage. There is discussion about possible protective mechanisms of the rupture for renal function in patients with obstructive uropathy.

We retrospectively analyzed the clinical presentation, predisposing factors and the renal function before and after treatment of 10 neonates with a rupture of the pyelum or urinary bladder in our hospital.

The group consisted of 9 boys and 1 girl. The average birth weight was 3,880 g. The patients presented with distended abdomen (n = 10), abdominal mass (n = 2), ascites (n = 5), oligohydramnion (n = 2), hypertension (n = 1) and anuria (n = 1). Underlying diagnosis included obstruction of the ureteropelvic junction (UPJ obstruction) in 3 children and posterior urethral valves in 7 children. Five children presented with urinoma, 3 children had a urinoma in combination with ascites and 2 children had isolated ascites. All children had reduced renal function at the time of diagnosis. In all 10 cases, the serum creatinine decreased after treatment. Scintigraphic investigation with mercapto-acetyltriglycerine (MAG III) demonstrated diminished function and perfusion of all 3 kidneys with UPJ obstruction and isolated urinoma even after treatment. Children with posterior urethral valves and urinoma revealed better function of the ruptured kidney and diminished function of the kidney which was not ruptured. One child with a rupture of the urinary bladder and urinary ascites showed good function and perfusion of both kidneys.

Perinatal ruptures of the uropoietic system are rare. The clinical presentation is aspecific. One should consider a rupture of the urinary bladder or pyelum in a neonate with a distended abdomen, hydronephrosis and ascites. The long-term prognosis depends on the underlying diagnosis and the location of the rupture. Probably, a UPJ obstruction with an isolated urinoma is associated with irreversible renal damage of the ruptured kidney. A rupture resulting in urinary ascites apparently provides better decompression with better function of the ruptured kidney. Scintigraphic investigation is necessary for a separate evaluation of the single kidney function.