A Retrospective Analysis of Ten Patients with Normal Alkaline Phosphatase and Primary Biliary Cholangitis

Abstract

Introduction: Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease which can be diagnosed when a patient tests positive for positive antimitochondrial antibody (AMA) and has a high alkaline phosphatase (AP) without the need for undergoing a liver biopsy. However, medical literature has documented that PBC can occur among patients with normal AP. As a result in patients worked up for common liver conditions like hepatitis and fatty liver, an incidental diagnosis of concomitant PBC can be missed if AMA is not ordered. We routinely perform AMA on patients who are evaluated for liver disease based on either imaging studies or abnormal liver tests and over last ten years came across patients with positive AMA and normal or near normal liver tests. We want to present this case series to highlight the importance of working up patients thoroughly with a battery of liver tests and if AMA is positive doing a liver biopsy to confirm the diagnosis of PBC.2732 Figure 1. Results of the study showing patient demographics, AMA range, ALP levels, presence of other autoimmune diseases and Liver biopsy resultsMethods: The charts of 10 patients with normal cholestatic liver enzymes and AMA positivity who underwent liver biopsy between 2012-2017 were retrospectively analyzed. Records were reviewed, cause of death verified when applicable, and all available clinical and biochemical data were collected, including detailed reports of liver histology. Only patients naïve to ursodeoxycholic acid were included in this case series. Results: Among the patient population, eight were females; median age was 56 years; median AMA titer was 50.3(lab reference 0-20); extrahepatic autoimmune disorders were present in five of ten patients including systemic lupus erythmatosis, Rheumatoid arthritis, Sjogren's syndrome, scleroderma and undifferentiated connective tissue disorder(Table 1). Two patients had cirrhosis on liver biopsy. The liver histology findings revealed PBC in all ten patients: 4 patients had early PBC changes, 2 patients had PBC with cirrhosis; 2 patients had PBC stage 2/4; and one patient each had changes of PBC associated with HCV and nonalcoholic steatohepatitis. Conclusion: AMA positive patients with normal cholestatic liver enzymes should be considered for a liver biopsy to establish a diagnosis of PBC. Based on this case series and data recently published in the literature, AMA should be ordered in patients worked up for common liver diseases. In the future, cost analysis of ordering AMA and the downstream benefit of deferring decompensated liver disease among PBC patients should be done.