Renal transplantation in secondary oxalosis

Short Bowel Syndrome and Kidney Transplantation: Challenges, Outcomes, and the Use of Teduglutide

Among patients with short bowel syndrome who commonly have kidney disease, kidney transplantation remains challenging. We describe the clinicopathologic course of a 59-year old man with short bowel syndrome secondary to Crohn's disease who underwent a deceased donor kidney transplant that was complicated by recurrent acute kidney allograft injury due to volume depletion from diarrhea, ultimately requiring the placement of permanent intravenous access for daily volume expansion at home resulting in the recovery of allograft function. Teduglutide treatment at 1.8 years post-transplant led to a dramatic decrease in diarrhea. A literature review of similar cases yielded 18 patients who underwent 19 kidney transplants. Despite high rates of complications, at the time of last follow-up (median 2.1 years [0.04-7]), 94% of the patients were still alive and 89% had functioning allografts, with a median eGFR of 37.5 [14-122] ml/min/1.73m². In conclusion, despite high rates of complications, kidney transplantation in patients with short bowel syndrome is associated with acceptable short- and midterm outcomes. Further, we report for the first time the effects of the glucagon-like peptide-2 analogue teduglutide for short bowel syndrome in a kidney transplant recipient.

Renal Allograft With Calcium Oxalate Deposition: Association with Urinary Tract Infection and Development of Interstitial Fibrosis

OBJECTIVES

The interaction between calcium oxalate deposition and urinary tract infection is not well established. We aimed to identify the association between these and to determine the role of calcium oxalate deposition on interstitial fibrosis development.

MATERIALS AND METHODS

Renal allograft biopsies of 967 patients were reviewed to identify those with calcium oxalate deposition in the renal allograft, with 27 (2.8%) identified. Follow-up biopsies were conducted to reevaluate for calcium oxalate presence and interstitial fibrosis development. At time of biopsy, presence of urinary tract infection and oxaluria was also examined from medical records.

RESULTS

Mean time for development of calcium oxalate deposition in renal allografts was 1.7 ± 0.4 and 32.7 ± 21.6 months in patients with primary and secondary oxalosis, respectively (P < .001). Of 27 patients with calcium oxalate deposition, 7 (25.9%) showed tubulointerstitial nephritis, with 2 also having urinary tract infection. Four patients (14.8%) had only urinary tract infection. Causes of tubulointerstitial nephritis were secondary to bacterial infection in 2 and secondary to viral infection in 5 patients (2 polyomaviruses, 2 cytomegaloviruses, 1 adenovirus). Time until development of interstitial fibrosis after calcium oxalate deposition was 3.5 ± 2.1 and 10.3 ± 4.1 months in patients with primary and secondary oxalosis, respectively (P = .01). Time until graft loss after calcium oxalate deposition was 9.3 ± 7.8 and 21.8 ± 12 months in those with primary and secondary oxalosis (P < .001), with 1-, 3-, and 5-year kidney graft survival of 43%, 28%, and 0% and 100%, 100%, and 67% in those with primary and secondary oxalosis, respectively.

CONCLUSIONS

Calcium oxalate deposits increased the risk of urinary tract infection and tubulointerstitial nephritis, with bacteria inducing increased presence of calcium oxalate deposition in a renal allograft. Calcium oxalate deposition had a significant influence on interstitial fibrosis development, therefore negatively affecting graft survival.

A Successful Approach to Kidney Transplantation in Patients With Enteric (Secondary) Hyperoxaluria

Background

Enteric hyperoxaluria due to malabsorption may cause chronic oxalate nephropathy and lead to end-stage renal disease. Kidney transplantation is challenging given the risk of recurrent calcium-oxalate deposition and nephrolithiasis.

Methods

We established a protocol to reduce plasma oxalic acid levels peritransplantation based on reduced intake and increased removal of oxalate. The outcomes of 10 kidney transplantation patients using this protocol are reported.

Results

Five patients received a living donor kidney and had immediate graft function. Five received a deceased donor kidney and had immediate (n = 1) or delayed graft function (n = 4). In patients with delayed graft function, the protocol was prolonged after transplantation. In 3 patients, our protocol was reinstituted because of late complications affecting graft function. One patient with high-output stoma and relatively low oxalate levels had lost her first kidney transplant because of recurrent oxalate depositions but now receives intravenous fluid at home on a routine basis 3 times per week to prevent dehydration. Patients are currently between 3 and 32 months after transplantation and all have a stable estimated glomerular filtration rate (mean, 51 ± 21 mL/min per 1.73 m²). In 4 of 8 patients who underwent for cause biopsies after transplantation oxalate depositions were found.

Conclusions

This is the first systematic description of kidney transplantation in a cohort of patients with enteric hyperoxaluria. Common complications after kidney transplantation impact long-term transplant function in these patients. With our protocol, kidney transplantation outcomes were favorable in this population with unfavorable transplantation prospects and even previous unsuccessful transplants.

Enteric oxalate nephropathy in the renal allograft: an underrecognized complication of bariatric surgery

Enteric hyperoxalosis is a recognized complication of bariatric surgery, with consequent oxalate nephropathy leading to chronic kidney disease and occasionally end-stage renal failure. In patients with prior gastrointestinal bypass surgery, renal allografts are also at risk of oxalate nephropathy. Further, transplant recipients may be exposed to additional causes of hyperoxalosis. We report two cases of renal allograft oxalate nephropathy in patients with remote histories of bariatric surgery. Conservative management led to improvement of graft function in one patient, while the other patient returned to dialysis. Interpretation of serologic, urine and biopsy studies is complicated by oxalate accumulation in chronic renal failure, and heightened excretion in the early posttransplant period. A high index of suspicion and careful clinicopathologic correlation on the part of transplant nephrologists and renal pathologists are required to recognize and treat allograft oxalate nephropathy. As the incidence of obesity and pretransplant bariatric surgery increases in the transplant population, allograft oxalate nephropathy is likely to be an increasing cause of allograft dysfunction.

Transplantation for renal failure secondary to enteric hyperoxaluria: a case report

Enteric hyperoxaluria can lead to renal failure. There have only been a few reports of renal transplantation as treatment of endstage renal disease secondary to enteric hyperoxaluria and results have been mixed. This report describes a patient with Crohn's disease who developed chronic renal failure from enteric hyperoxaluria. He subsequently had a successful renal transplant without any post-operative oxalate related complications and has satisfactory renal function almost three years later. Aggressive pre-transplant hemodialysis was not done. The literature associated with renal transplantation for enteric hyperoxaluria is reviewed.

Enteric hyperoxaluria: a hidden cause of early renal graft failure in two successive transplants: spontaneous late graft recovery

A 37-year-old patient underwent two successive renal transplantations 7 months apart. He remained dialysis dependent. Early biopsy of both grafts revealed widespread calcium oxalate deposition suggestive of acute oxalate nephropathy. Several causes of oxalate nephropathy, including primary oxalosis and an increased intake of oxalic acid precursors, were excluded. Two years later, the identification of steatorrhea with radiologic signs of chronic pancreatitis led to the hypothesis of enteric hyperoxaluria. Surprisingly, 11 months after the second transplantation, graft function improved progressively allowing interruption of dialysis. Three years later, renal function is stable. The causes and prevention of acute oxalate-induced graft failure are highlighted. Subclinical evidence of enteric hyperoxaluria should be looked for and appropriate therapy instituted as early as possible. The possibility of a late recovery of renal function warrants attentive patience from attending physicians.

Oxalate nephrosis and renal sclerosis after renal transplantation in a cat

A 10-year-old castrated domestic shorthair cat received two renal allografts, 14 days apart, for the treatment of chronic renal failure. Oxalate nephrosis developed in both allografts, and they became nonfunctional. During the transplantation period, the cat was not exposed to exogenous sources of oxalate, and there was no evidence of primary type 2 hyperoxaluria before surgery. Urologic surgery, in particular renal transplantation, has been identified as a factor that can precipitate renal failure in human patients with decompensated renal function and hyperoxaluria. If hyperoxaluria was present before surgery in this cat, it was most likely caused by increased absorption or decreased metabolism of dietary oxalate.