Refractory ascites induced by mycophenolate in a pediatric kidney transplant patient

Common side effects of mycophenolate mofetil (MMF) are diarrhea, leukopenia, and infectious complication. The polymorphisms of enzymes affecting MMF clearance could be related to MMF toxicity, and in vitro study revealed that high MMF levels might cause endothelial dysfunction. A 7-year-old Korean male with end-stage renal disease on peritoneal dialysis due to mesangial proliferative glomerulonephritis received a kidney transplantation (KT) from a deceased donor, and immunosuppressive medications including MMF, tacrolimus, and methylprednisolone were started after KT. The patient developed oliguria immediately after surgery, and therapeutic plasmapheresis was initiated with continuous renal replacement therapy for the possibility of graft dysfunction and nephrotic syndrome relapse. Renal function recovered 4 days later, but the patient developed ascites. Diagnostic paracentesis revealed findings that were interpreted as uncomplicated ascites in cirrhosis, not of renal origin. Abdominal ultrasonography showed increased parenchymal echogenicity without cirrhotic change in the liver. Based on a case report and differential diagnosis, we replaced MMF with azathioprine, and 4 weeks later a sudden increment in urine output was detected. Eleven months after KT, the patient is free from ascites. The UGT2B7 802 polymorphism was tested, and wild-type UGT2B7 802 was detected, which is related to low MMF clearance. The low clearance of MMF by UGT2B7 802 wild-type polymorphism might have led to MMF toxicity affecting endothelial dysfunction. This case suggests that refractory ascites could be induced by MMF, and endothelial damage is a possible mechanism.