S5911 Bile Cast Nephropathy in a Post-Liver Transplant Patient: A Diagnostic and Management Challenge

Introduction: Cholemic nephrosis, also known as bile cast nephropathy, is a kidney condition caused by elevated bilirubin. It is commonly associated with severe liver dysfunction. We present a case of cholemic nephrosis in a diseased liver transplant recipient. Case Description/Methods: A 46-year-old man with history of alcoholic cirrhosis status post diseased liver transplant (LT) was admitted due to a week of worsening jaundice and pruritus. On admission, his vitals were normal, but labs disclosed elevated liver enzymes and total bilirubin concerning for cholestatic injury. He reported the use of herbal supplements including milk thistle and many “liver detox” medications. Liver ultrasound revealed patent hepatic vasculature with normal velocities. MRCP showed no evidence of intrahepatic or extrahepatic biliary ductal dilation with CBD measuring 6 mm. Due to his markedly elevated creatine, a renal ultrasound was completed showing no obstruction or hydronephrosis. He underwent ERCP with empiric biliary sphincterotomy and stent placement; however, this did not alleviate his hyperbilirubinemia. Liver biopsy was pursued which showed no evidence of acute cellular rejection, interface hepatitis, steatosis, or fibrosis. Despite intravenous hydration, he had progressive kidney injury prompting renal biopsy. Results were consistent with acute bile nephropathy (cholemic nephrosis) with associated acute tubular injury. Given the severity of his kidney injury, the patient became dependent on hemodialysis. Discussion: Acute and chronic kidney disease is common in the post-LT population. Cholemic nephrosis is a type of acute kidney injury in the setting of liver dysfunction. The toxic effects of bilirubin and its casts can impair renal tubular function leading to kidney failure. In this case, after ruling out infectious and obstructive etiologies, the likely cause of hyperbilirubinemia was drug induced liver injury (DILI). Silymarin is the primary active compound in milk thistle, and its use for protective effects on the liver is controversial, especially in the transplant population. Most patients with DILI recover without long-term sequela. However, high total bilirubin, elevated international normalized ratio, low albumin, and pre-existing liver disease are risk factors for adverse outcomes. The mainstay treatment is supportive care including the use of antiemetics, analgesics, antipruritic, and parenteral hydration as needed. In severe cases, cholemic nephrosis can lead to dependency on hemodialysis.