Fetal urinoma: A case report and review of the literature

Abstract

Fetal urinomas are a rare but important sonographic finding. Urinomas are peri‐renal collections of urine, formed after the rupture of the kidney secondary to an underlying urinary tract obstruction or trauma. Diagnosis antenatally is important for ongoing monitoring and postnatal follow up as their presence may indicate reduced or absent kidney function in the affected kidney.

Fetal Urinoma Due to Circulatory Disorders in an Umbilical Artery: Case Report

“…It can result from traumatic amniocentesis; 9 however, most reported cases are associated with obstructive uropathy, usually secondary to posterior urethral valves, or ureteropelvic junction obstruction. 2,10 Increased pressure secondary to the obstruction leads to extravasation of urine into the perirenal fat, followed by lipolysis and inflammatory reaction with the consequent formation of a fibrous sac around the collected urine. 11 The extravasated urine can be presented in the form of a localized collection such as urinoma or generalized, e.g., ascites or rarely pleural effusion.…”

“…The proposed etiologies of leakage include different types of urinary tract obstruction, neoplastic or iatrogenic causes. 2 However, there are no published cases of urine leakage resulting from bladder wall ischemic necrosis in fetuses.…”

Urinoma

“…Urinomas are encapsulated collections of urine around the kidney. 2 Some speculate that the kidney rupture that gives rise to a urinoma serves as a protective mechanism for the renal parenchyma in the setting of increased pressure due to obstruction. 1 Others interpret the presence of a urinoma as evidence of an already compromised renal parenchyma.…”

“…Depending on its location in the perinephric space, a large urinoma can displace the kidney anteriorly or posteriorly. 2 In addition to the presence of a fluid collection, an underlying urinary tract obstruction should also be observed, such as bladder outlet obstruction or bilateral hydroureteronephrosis. There may be evidence of a decompressed urinary tract obstruction because of rupture, with findings of a thickened bladder wall or renal dysplasia.…”

“…3 Small urinomas may be mistaken for a dilated calyx in the presence of hydronephrosis; identifying a mass effect on the renal cortex can aid in distinguishing these two diagnoses. 2,3 In addition, intra-abdominal ascites can mimic a urinoma; a thorough evaluation of fluid in other compartments is warranted. There have also been cases of urinoma formation after trauma sustained during amniocentesis.…”