Autoimmune acute liver failure: an emerging etiology for intractable acute liver failure.

Diagnosis of acute onset autoimmune hepatitis (AIH) is the most challenging task because of atypical clinicopathological features. We examined the nature of acute onset AIH consisting of nonsevere, severe, and fulminant AIH based on our published data and other published papers, and propose how to diagnose and treat this intractable hepatitis. We analyzed clinical, biochemical, immunological, radiological, and histological features of acute onset AIH. Thirty percent of fulminant hepatitis was due to AIH and autoimmune acute liver failure (ALF) was not rare. The important characteristic of acute onset AIH is its histological, radiological, and clinical heterogeneity. Sometimes acute onset AIH develops into ALF in a sub-acute clinical course without appropriate diagnosis and treatment, and becomes resistant to immunosuppressive therapy and has poor prognosis. Unenhanced computed tomography (CT) often shows heterogeneous hypoattenuation in autoimmune ALF. The revised original scoring system (1999) performed better in patients with acute onset AIH than the simplified scoring system (2008). Liver regeneration from periportal progenitor cells to mature hepatocytes was impaired in ALF, resulting in resistance to immunosuppressive therapy. Precise histological evaluation (the presence of centrilobular necrosis/collapse) along with the revised original scoring system and CT findings of heterogeneous hypoattenuation after systematic exclusion of other causes 36 plays an important role in the diagnosis. The most important strategy for autoimmune ALF is to diagnose and treat acute onset AIH before its development into ALF. Liver transplantation should be considered before the occurrence of infectious complications in the case of fulminant liver failure.