Calcifications in a Continent Urinary Diversion
A 37-year-old man with a history of spina bifida presented with an audible knocking sound coming from his abdomen during ambulation. Fifteen years earlier he had undergone a cystectomy with a continent cutaneous urinary diversion (Indiana pouch) for a neurogenic bladder. He had been poorly compliant with the catheterization and irrigation regimen involving the pouch.
Physical examination revealed a well-healed, functional stoma and a palpable mass in the right side of the abdomen. Urinalysis revealed a urinary pH of 9.0, with numerous white and red cells, and urine culture grew Proteus mirabilis.
Plain abdominal radiography revealed two large multilaminar calcifications in the right side of the abdomen (Panel A). Computed tomography of the abdomen and pelvis confirmed the presence of two large calculi within the Indiana pouch (Panel B). The patient underwent cystolithotomy without incident. At a follow-up visit 1 year after the procedure, he was found to have been compliant with his catheterization and irrigation regimen and remained free of stones.
Continent urinary diversions may be associated with hypercalciuria, hyperphosphaturia, hyperoxaluria, and hypocitraturia, all of which may predispose patients to pouch urolithiasis. Infections with organisms that break down urea can result in an alkaline environment, which can in turn give rise to struvite (magnesium ammonium phosphate) stones. Establishment of a formal catheterization and irrigation protocol for continent urinary diversions may reduce the risk of urolithiasis.