Spontaneous bilateral renal pelvis rupture during CT in the absence of urinary tract obstruction: case report

Background: Atraumatic renal pelvis rupture without pre-existing renal or ureteric pathology is an uncommon event. It is reported in the setting of acute urinary tract obstruction, most often secondary to ureteric calculi. Typical symptoms include acute flank pain and nausea, mimicking pyelonephritis or other causes of acute abdomen. Spontaneous rupture occurring bilaterally without identifiable urinary tract obstruction is exceedingly rare, and has yet to be reported in current English literature. Possible contributing pathophysiological mechanisms can be postulated from reported cases of rupture with observed obstruction.

Case presentation: A 58-year-old woman undergoing multiphasic computed tomography (CT) for evaluation of asymptomatic microscopic haematuria developed on-table bilateral renal pelvis rupture seen only after contrast administration, on the delayed phase. There was no significant past medical history of note. The patient remained asymptomatic throughout and after the study, and was managed conservatively. Follow-up radiographical imaging over a month showed resolution of urinoma and no further contrast extravasation. No complications or recurrence was subsequently noted.

Conclusions: Spontaneous rupture of the renal pelvis can be a rare complication of intravenous contrast administration even in cases without identifiable urinary tract obstruction, and it can occur bilaterally. Cases can uncommonly be asymptomatic but typical symptoms should prompt evaluation of the kidneys, particularly when they are not included in the initial study or no delayed phase is protocolled. Interval imaging for resolution of urinoma and contrast extravasation is clinically relevant to monitor for and avoid infective sequelae.

Keywords: Case report; Contrast-induced osmotic diuresis; Forniceal rupture; Pyelosinus backflow; Spontaneous renal pelvis rupture.