Acute liver failure is the appearance of severe complications rapidly after the first signs (such as jaundice) of liver disease, and indicates that the liver has sustained severe damage (loss of function of 80¨C90% of liver cells). The complications are hepatic encephalopathy and impaired protein synthesis (as measured by the levels of serum albumin and the prothrombin time in the blood). The 1993 classification defines hyperacute as within 1 week, acute as 8¨C28 days, and subacute as 4¨C12 weeks;[1] both the speed with which the disease develops and the underlying cause strongly affect outcomes.[2]

Reference
Wiki: Acute liver injury