Spontaneous Perinephric Urinoma Secondary to Drug Induced Acute Interstitial Nephritis: A Case Report

Abstract Urinoma is defined as the extravasation of urine from any part of the urinary collecting system, which causes lipolysis of the surrounding fat, resulting in an encapsulated collection. The most common cause of urinoma is the direct obstruction of the urinary system. The other etiologies include trauma and postinstrumentation/surgery. Parenchymal cause for spontaneous urinoma is exceedingly rare. We present a case of a 30-year-old gentleman who presented with lower abdominal pain and was treated with a Diclofenac injection. The pain got better temporarily, but he presented again with right loin pain after 3 days. His computed tomography scan images revealed bilateral perinephric urinoma. As there was significant deterioration of renal function, he underwent a renal biopsy. The histopathology was reported as acute interstitial nephritis (AIN). Drug-induced AIN is very rarely presented with acute loin or abdominal pain due to spontaneous perinephric urinoma, as it was seen in our case.