Acute presentation of autoimmune hepatitis -from acute hepatitis to ALF and ACLF.

Acute presentation of autoimmune hepatitis (AIH) occurs in 22-43% of all AIH cases, and is not a rare condition. Rather than constituting a single disease entity, it represents a clinical spectrum characterized by considerable variability in severity and the presence of preexisting chronic AIH. This spectrum ranges from acute AIH and acute severe AIH to AIH presenting as acute liver failure (ALF) or as acute-on-chronic liver failure (ACLF), contingent upon factors such as coagulopathy, hepatic encephalopathy, and underlying liver disease. Diagnosing acute presentation of AIH can be particularly challenging due to the frequent absence of classical serologic signatures such as autoantibodies and elevated IgG levels. Histopathological examination remains essential for diagnosis, typically necessitating percutaneous or transjugular liver biopsy. Corticosteroids (CS) are recommended for the management of acute AIH and acute severe AIH with coagulopathy. However, the therapeutic response to CS should be meticulously monitored. If a poor response is anticipated, liver transplantation (LT) should be promptly considered. For AIH presenting as ALF with encephalopathy or ACLF with advanced underlying liver disease, LT is generally advised. Nonetheless, there is potential for a trial of CS therapy in cases of ALF with low MELD scores or ACLF without encephalopathy. This review provides an overview of the latest findings concerning the definition, diagnosis, and management of acute presentation of AIH.