Acute-on-chronic liver failure (ACLF) is a syndrome characterized by acute and severe decompensation of chronic liver disease (CLD) correlated with multiple organ failure, poor prognosis, and increased mortality. In 40–50% of ACLF cases, the trigger is not recognized; for many of these patients, bacterial translocation associated with systemic inflammation is thought to be the determining factor; in the other 50% of patients, sepsis, alcohol consumption, and reactivation of chronic viral hepatitis are the most frequently described trigger factors. Other conditions considered precipitating factors are less common, including acute alcoholic hepatitis, major surgery, TIPS insertion, or inadequate paracentesis without albumin substitution. Host response is likely the primary factor predicting ACLF severity and prognosis, the host immune response having a particular significance in this syndrome, together with the inflammatory cascade. The management of ACLF includes both the prevention of the precipitating factors that lead to acute liver decompensation and the support of vital functions, the prevention and management of complications, the estimation of prognosis, and the opportunity for liver transplantation.
