Diagnosis of Autoimmune Hepatitis

AIH is a perplexing entity to diagnose due to its relative rarity and heterogenous presentation. It can present at varying ages, with varying chronicity, and is even dividedinto 2 major subtypes. AIH offers no pathognomonic findings, instead relying on clinical presentation, serology, and histology to make the diagnosis. The scoring systems described above are designed as tools to aid in diagnosis as well as to define research cohorts. However, they are not a substitute for clinical judgment. Specifically, in less typical scenarios including concomitant liver disease or the presence of an overlap syndrome, these criteria fail to demonstrate the same diagnostic utility. Detection of autoantibodies is an alternate tool to aid in diagnosis. Typical autoantibodies such as ANA, SMA, and anti-LKM1 have proven utility in diagnosis and even prognosis. Several others provide additional information when typical autoantibodies are absent. A plethora of other markers may rise to clinical importance as standardization of and technologies behind assays improve. Histological analysis remains the cornerstone of diagnosis and to this day biopsy is essential to make the diagnosis. The 3 hallmark features of AIH on biopsy are interface hepatitis, emperipolesis, and rosette formation, which are reflected on diagnostic scoring systems accordingly. Other supportive findings may also have prognostic implications. Overlap syndromes pose additional diagnostic uncertainty because traditional scoring systems demonstrate poor performance characteristics. Recognition is important because clinical courses and response to treatment may vary.