The reasoning: definition creates urgency
Acute liver failure is acute liver injury with INR at least 1.5 and any hepatic encephalopathy in a patient without pre-existing cirrhosis, usually within 26 weeks. Acute-on-chronic liver failure is different. Causes include acetaminophen, viral hepatitis, drug-induced liver injury, autoimmune hepatitis, Wilson disease, pregnancy-related disease and ischaemic injury.