What are the potential causes for urinoma?
High grade urinary tract obstruction - potentially from any cause, such as tumour, ureteric stone or a congenital PUJ obstruction may be responsible. Trauma is another major cause - this may be do novo trauma or iatrogenic, such as following a nephrostomy, PCNL or renal biopsy which traumatizes the collecting system.
How is a urinoma best illustrated with imaging?
Although a fluid collect adjacent to the kidney is suspicious in the correct clinical circumstances, an excretory phase CT (CT IVU) will best demonstrate extravastation from the collecting system, confirming a urinoma.
What is the management of a urinoma?
Small urinomas may be managed conservatively - at most follow up imaging to ensure resolution. Large or persistent urinomas may be drained percutaneously under image guidance.
Delayed phase CT scan obtained 1 hour later shows increased attenuation of the urinoma. Note the contrast material in the right perinephric space. There is also evidence of hydronephrosis on the right side.