Problems of ultrasonography in the diagnosis of acute renal failure

Introduction: Ultrasonography is the appropriate method for diagnosis of an acute postrenal insufficiency. Anatomic variations of the collecting system can result in missleading ultrasonography findings. Case report: We report the clinical course of a 71-year-old patient who underwent open suprapubic prostatectomy due to an enlarged benign prostatic hyperplasia. In the immediate postoperative period, acute renal insufficieny occurred. Ultrasonography of both kidneys demonstrated almost normal findings without significant dilatation of the renal collecting system. In the preoperative urography, an intrarenal small renal pelvis was identified. After placement of ureteral catheters, the significantly increased serum creatinine declined immediately to within the normal range. Conclusions: In patients with acute renal insufficiency, a normal ultrasonography finding does not always exclude a postrenal cause.