LAUSR

A 50-year-old man with a history of type 2 diabetes was referred for acute kidney injury (AKI) with a serum creatinine level of 6.69 mg/dL and an HbA1c value of 12.7%. Computed tomography revealed a markedly dilated bladder (Picture a), far beyond the level of the umbilicus (Picture b, arrow). Bilateral hydronephrosis with no anatomical urinary tract obstruction was observed (Picture c), so postrenal AKI due to severe diabetic cystopathy was diagnosed. The patient complained of neither severe urinary urgency nor abdominal discomfort; however, a urine outflow of over 3.0 L was observed through a urethral catheter in a short time, and a urine output of approximately 5 L was observed over the next 20 hours, suggesting potentially significant urinary retention. The patient had no history of trauma or anticholinergic drug use. Diabetic cystopathy is a serious complication of diabetes that progresses latently (1). An impaired sensation of bladder distention is a late-phase manifestation of diabetic cystopathy (2), with the bladder visible as a bulge below the level of the umbilicus. In the present case, although the serum creatinine level improved to 0.92 mg/dL on day 5, urethral catheter management was required after discharge.