Torsion of Renal Transplant 10 Years After Simultaneous Kidney-Pancreas Transplantation: Imaging as a Diagnostic Tool

Abstract

Renal transplant torsion around its pedicle is a rare technical complication of intraperitoneal renal transplantation. Intraperitoneal placement allows more transplant mobility, which increases the risk of torsion. The length of the vascular pedicle, excess ureteral length, and paucity of adhesion secondary to steroid administration are factors that also contribute to the abnormal mobility of the kidney (1). One of the diagnostic difficulties of renal torsion is its lack of specific clinical features. A high level of suspicion is needed to diagnose renal transplant torsion because it may mimic rejection and venous thrombosis. Therefore, imaging studies play a crucial role in renal torsion diagnosis. We report a case of a 48-year-old woman, with simultaneous kidney-pancreas transplant (SKPT), who developed torsion of the transplanted kidney 10 years after transplantation. She had SKPT in 1997 after developing end-stage renal disease secondary to type 1 diabetes mellitus. She was on prednisone, cyclosporine, and mycophenolic acid. Her baseline serum creatinine level was 1.1 mg/dL. Ten years later, she presented with a 3 days history of nausea, vomiting, loose stool, and anuria. On physical examination, she was markedly hypotensive and severely dehydrated, and she had mild left lower quadrant abdominal tenderness. On admission, her serum creatinine level was 6.2 mg/dL, blood glucose 93 mg/dL, serum amylase 38 mg/dL, and a trough cyclosporine was 81 ng/mL. A renal ultrasound scan showed mild pelvicaliectasis with no apparent change from a study 2 years prior. Doppler sonography showed normal arterial waveforms. Patient was aggressively resuscitated with crystalloids with no improvement in her urine output or serum creatinine level. A renal biopsy was performed, which did not show any significant pathologic changes. There was no evidence of rejection on the biopsy. A computed tomography (CT) scan of the transplanted kidney showed moderate degree of hydronephrosis and swelling around the transplanted kidney (Fig. 1b vs. a). An antegrade nephrostogram demonstrated a corkscrew-like configuration of the proximal ureter with neither opacification of the more distal ureter nor the urinary bladder. A percutaneous nephrostomy tube was placed and a copious amount of urine returned.FIGURE 1.: Pelvic renal transplant (b) shows moderate changes of hydronephrosis and dilatation of the renal collecting system compared with prior computed tomography scan (a).The patient was taken to the operating room. At laparotomy, the kidney was found twisted 180° around its pedicle with no compromise to the vascular structures. However, it was apparent that the “volvulized” transplant kidney had induced a rotational obstruction of the transplant ureter at the insertion of the bladder. The torsion was straightened, and a nephropexy of the kidney to the left colon and the anterior abdominal wall was performed. Postoperatively her serum creatinine level decreased to 0.9 mg/dL, and she was discharged home in stable condition. CT scan is more sensitive than renal ultrasound in detecting torsion of the transplanted kidney. CT imaging may show changes in renal orientation as well as secondary changes such as swelling, hydronephrosis, or abnormal enhancement (2). The most suggestive imaging sign of renal transplant torsion is the change in the axis of the transplanted kidney, which can be facilitated by comparison with baseline scans as demonstrated in our case. To our knowledge, this is the first case report of SKPT recipient who developed torsion of the transplanted kidney 10 years after transplantation. Samir Nangia Department of Internal Medicine Medical College of Wisconsin Milwaukee, WI Ehab R. Saad Division of Nephrology Medical College of Wisconsin Milwaukee, WI