1437 Overlap Syndrome of Primary Sclerosing Cholangitis and Primary Biliary Cholangitis: A Case Report

Abstract

INTRODUCTION: Primary sclerosing cholangitis (PSC) is characterized by inflammatory changes within the extra-and intrahepatic bile ducts and subsequent development of strictures. Primary biliary cholangitis (PBC) is characterized by progressive destruction of intrahepatic bile ducts, typically associated with a positive anti-mitochondrial antibody. Both of these disease processes are rare, chronic cholestatic liver diseases, with possible outcomes of progression to cirrhosis and need for liver transplant. CASE DESCRIPTION/METHODS: A 55-year-old gentleman from West Africa with no significant past medical history presented with intractable pruritus, weight loss, polyuria and polydipsia, found to have new onset diabetes. His other laboratory data revealed cholestasis, with alkaline phosphatase 401 U/L, aspartate aminotransferase 100 U/L, alanine aminotransferase 160 U/L, direct bilirubin 0.37 mg/dL on laboratory examination. Magnetic resonance imaging of his abdomen was unremarkable for any biliary dilatation or etiology of his cholestatic liver injury. Liver biopsy was remarkable for non-specific lymphocytic portal inflammation. Other diagnostic work up was remarkable for negative autoimmune diabetes work up. He was subsequently lost to follow up and re-presented five years later with intractable pruritus. Repeat MRI of his abdomen revealed a beaded and irregular appearance of the extra and intrahepatic bile ducts, concerning for PSC (Figure 1). He was started on cholestyramine with minimal improvement in pruritus. Repeat liver biopsy revealed focal bile duct injury. Laboratory examination revealed an elevation of anti-mitochondrial antibody (AMA). These findings were consistent with a diagnosis of overlap syndrome of PBC and PSC. Treatment with ursodeoxycholic acid (UDCA) was started; however, given lack of improvement in biochemical profile, fenofibrate was added. The patient was subsequently hospitalized for rhabdomyolysis with acute kidney injury in setting of fenofibrate use. The patient developed cirrhosis and subsequent decompensation of hepatic encephalopathy and ascites approximately twenty months after his initial diagnosis of overlap syndrome. He is currently undergoing transplant evaluation. DISCUSSION: This is a rare case of overlap syndrome of PBC and PSC. At present, there are no consensus guidelines on the diagnosis and management of this syndrome. Given the rarity of this condition, there is currently no available data on long term outcomes in patients with overlap of PBC and PSC.