Osmotic nephrosis in a renal transplant recipient

Abstract

CASE PRESENTATION A 59-year-old Hispanic male with a history of type II diabetes mellitus, hypertension, and end-stage renal disease (on hemodialysis for 2 years) was called in for a kidney transplant. He was in his usual health, having received dialysis earlier in the day. The kidney donor was from an expanded criteria pool and was a 59-year-old Caucasian male with diabetes mellitus who expired following a cerebrovascular accident. He had a terminal creatinine of 1.3mg/dl (114.92 μmol/l (nl range 0.6-1.2 mg/dl/53.04-106.08 μmol/l)) and no evidence of proteinuria. A donor renal biopsy revealed 10-15% tubular atrophy and interstitial fibrosis. There was a six-antigen mismatch, and cold ischemia time was 31 h. The final complement-dependent cytotoxic and flow cytometry crossmatch were negative. Renal transplantation was performed. At the time of transplantation, the patient received alemtuzumab (Campath; anti-CD52 monoclonal antibody) and solumedrol as induction therapy. The patient had an intra-operative episode of hypotension that resolved with a 500 ml bolus of normal saline and 250 ml of 6% hetastarch lactate electrolyte solution. At the completion of surgery, the patient was stable and was extubated and moved to recovery. On physical exam, he was normotensive with normal sinus rhythm, clear lungs, good dorsalis pedis pulses, and no peripheral edema. He had been anuric before surgery, but had made 10 ml of urine during the first hour. One hour after surgery, the patient's systolic blood pressure dropped to 80 mmHg. In an effort to sustain his blood pressure, he was given multiple boluses of normal saline, lactate Ringers solution, and an additional 11 of 6% hetastarch. He was eventually started on vasopressin and moved to the Intensive Care Unit. His hematocrit remained stable, but his potassium was elevated at 6.0 mM/I. Continuous renal replacement therapy was initiated. Renal ultrasound initially was unable to demonstrate arterial or venous blood flow. After 4 h, his blood pressure improved and he was weaned off vasopressin. A repeat ultrasound 24 h later showed restoration of arterial and venous blood flow. Maintenance immunosuppression was started on post-operative day 1 and included tacrolimus and mycophenolate mofetil. His tacrolimus trough level ranged between 9 and 13 ng/ml. The patient remained oliguric and hemodialysis-dependent during the first week. Due to delayed graft function and a creatinine of 6.2 mg/dl (548.08 μmol/l), renal allograft biopsy was performed on post-operative day 8.