Excessively Long Duodenum of the Pancreatic Graft Segment as a Rare Cause of Hyperammonemia After Simultaneous Pancreas-Kidney Transplant.

Simultaneous pancreas-kidney transplant is currently standard therapy to achieve long-term insulin-free euglycemia in patients with type 1 diabetes mellitus and concomitant end-stage kidney failure. A patient with symptoms of encephalopathy caused by hyperammonemia and with new-onset iron deficiency anemia was admitted to our institution 20 months after a simultaneous pancreas-kidney transplant. Detailed screening did not reveal any specific cause for the hyperammonemia, and despite standard treatment, hyperammonemia did not resolve. An abdominal computed tomographic scan was performed, which showed a distended duodenal segment of the pancreas graft. This was confirmed during exploratory laparotomy when the anastomosis between duodenum and ileum was dismantled and found not to be stenotic. The excessively long stumps of the duodenum were then dissected and shortened, and a new anastomosis between graft-duodenum and recipient-ileum was created. The operation was followed by an uncomplicated postoperative course in which the serum ammonia normalized on the first postoperative day and remained normal afterwards. An excessively long segment of the duodenum of the pancreatic graft may lead to encephalopathy with hyperammonemia after a simultaneous pancreas-kidney transplant. This emphasizes the need for meticulous preparation of the graft to avoid this complication.

2,8-Dihydroxyadenine Nephropathy Identified as Cause of End-Stage Renal Disease After Renal Transplant.

Adenine phosphoribosyltransferase deficiency is a rare autosomal recessive disorder of uric acid metabolism that leads to formation and excretion of 2,8-dihydroxyadenine into urine. The low solubility of 2,8-dihydroxyadenine results in precipitation and formation of urinary crystals and renal stones. Patients with this disorder usually have recurrent nephrolithiasis and can develop nephropathy secondary to crystal precipitation in the renal parenchyma. The disease is most often underdiagnosed and can recur in renal transplant, causing graft failure. Lack of specific clinical manifestations, chemical and radiologic features identical to those shown with uric acid stones, and lack of awareness among clinicians are among the causes for the underdiagnoses of this treatable disease. Allopurinol, a xanthine dehydrogenase inhibitor, is the mainstay of treatment, supported by high fluid intake and dietary modifications. The possibility of adenine phosphoribosyl transferase deficiency should be considered in all cases of urolithiasis in children, patients with recurrent urolithiasis, and patients with urolithiasis associated with renal failure of unknown cause, including patients with end-stage renal disease and renal transplant recipients. Here, we report a case of a 41-year-old female patient who had a late diagnosis of 2,8-dihydroxyadenine nephropathy-induced end-stage renal disease, made on the native nephrectomy that accompanied the renal transplant, and who had a timely intervention that prevented recurrence in the graft.