Conversion from cyclosporin to tacrolimus in a patient with prolonged acute tubular necrosis

Abstract

Acute tubular necrosis (ATN) is a common condition following cadaveric renal transplantation with an incidence in many series of nearly SO %. The aetiology is uncertain; however, it would appear to be related to damage to the transplant kidney either prior to retrieval, during cold preservation or during re-warming of the kidney at the time of anastamotic construction. There is no specific therapy for ATN and treatment is comprised of an expectant policy with supportive dialysis and fluid restriction. Renal function improves in the majority of cases, though there may be delayed function for several weeks. We report a case of dialysis-dependent ATN that had persisted for S months following transplantation. Following conversion to tacrolimus there was immediate improvement in renal function, and after a month of tacrolimus therapy the patient was dialysis-independent.Key words Acute tubular necrosis, tacrolimus, cyclosporin . Tacrolimus, ATN, cyclosporin . Cyclosporin, ATN, tacrolimus . Conversion, cyclosporin, tacrolimus In trod udionTacrolimus (Prograf) has been shown in clinical trials to be effective both as primary immunosuppression therapy and in the treatment of refractory rejection [5,9]. We have recently had success with tacrolimus in the treatment of a patient with primary non-function secondary to acute tubular necrosis (ATN) that had persisted for S months following transplantation. Case reportA 41-year-old gentleman underwent cadaveric renal transplantation in October 1995 for hypertensive nephropathy. The donor was a young male who had died from a cerebral haemorrhage. The human leucocyte antigen (HLA) mismatch was 1:2:0. Whilst on the intensive care unit the donor experienced a single hypotensive episode lasting 30 min; however, he maintained a good urine output throughout. The kidney was preserved in University of Wisconsin preservation solution and the cold ischaemia time was 16 h and 55 min.A small lower pole artery that had been damaged at the time of retrieval was anastamosed end-to-side to the main renal artery, and the anastamosis time for the renal-iliac anastamosis was 40 min. At the time of the recipient operation, the lower pole of the kidney was noted to be poorly perfused.The patient was commenced on triple therapy immunosuppression consisting of cyclosporin 8 mg/kg per day, azathioprine 1.5 mg/ kg per day and prednisolone 0.3 mg/kg per day. Dosing of cyclosporin (Neoral) was based on 12-h trough levels that aimed to maintain blood concentrations of 80-200 ng/ml (Emit assay). The dose of azathioprine and steroids remained constant. The patient also received the standard supplementary therapy that included nifedipine 10 mg twice daily, ranitidine 150 mg once daily, co-trimoxazole 480 mg twice daily and amphotericin lozenges 4 per day.The transplant kidney exhibited primary non-function and the patient remained anuric. A duplex ultrasound scan demonstrated thrombosis of the lower pole renal artery with approximately 10