Primary Hyperoxaluria Type 2: Is Combined Liver Kidney Transplant the Answer?

Résumé fourni par la source

Introduction: Primary Hyperoxaluria (PH) is a group of rare inborn errors of glyoxylate metabolism characterized by overproduction of oxalate. Oxalate is poorly soluble and is deposited as calcium oxalate in various organs, with the kidneys being the prime target leading to ESRD. Case Description: 60-year-old female with a history of diabetes, hypertension and ESRD 2/2 obstructive uropathy from staghorn calculi in 2017. Patient underwent bilateral native nephrectomies in 2018 for staghorn calculi and was started on hemodialysis. Pathology showed extensive intratubular calcium oxalate crystals. Patient underwent a living donor kidney transplant in 2019 in India with allograft dysfunction by 2 months. Transplant biopsy showed oxalate deposition and severe ATN. 24-hr urine oxalate level was 182 mg. Genetic testing showed homozygosity for pathogenic variant in GRPHR gene, consistent with PH type-2. Repeat biopsy in 2020 confirmed oxalate nephropathy. Patient was started on daily dialysis for oxalate clearance. Pre-transplant plasma oxalate level on dialysis was 38mg. She underwent simultaneous liver-kidney transplant in 2021. Post-operatively, patient was maintained on CRRT for 4 days and transitioned to daily dialysis thereafter for delayed graft function and anuria. Renal allograft biopsy showed ATN and oxalate crystals. Patient was discharged on daily dialysis with serum oxalate level of 15. Patient finally recovered her kidney function almost 4 months later with current 24-hour creatinine clearance 25ml/min and 24-hour oxalate level of 55mg. Discussion: PH type-2 was thought to have a more favorable prognosis than PH type-1 however, recent studies have found this disease has significant morbidity. While it was thought that a renal transplant may be the treatment for this ‘milder’ disease as oxalate deposition may take longer than the life of the allograft, reports have shown that recurrent PH type-2 has led to early post-transplant renal function loss. Dhondup and Del Bello each reported a case of successful treatment of PH type-2 with simultaneous liver-kidney transplantation. Similarly, while our patient remained dialysis dependent for almost 4 months post combined liver-kidney transplant, she is now successfully off dialysis. These 3 cases support the idea of a combined liver-kidney transplant as a better option for PH type-2.

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