ICU · GI/Nutrition

Acute liver failure (hepatic failure)

Also known as Acute liver failure (ALF) · Fulminant hepatic failure · King's College Criteria · N-acetylcysteine (NAC) · Liver transplant for ALF · Cerebral oedema in ALF · O'Grady classification · Hyperacute / acute / subacute liver failure

Acute liver failure (ALF) is severe acute liver injury with encephalopathy and coagulopathy (INR >1.5) within 26 weeks, in a patient without pre-existing liver disease. Classification by tempo (O'Grady): hyperacute (<7 days), acute (8-28 days), subacute (29 days-12 weeks) — prognosis varies by interval. Causes: paracetamol (1 in UK/Aus), drug-induced (idiosyncratic), viral hepatitis (HBV 1 viral), Wilson disease, pregnancy-related (AFLP, HELLP), mushroom (Amanita phalloides), ischaemic, autoimmune, indeterminate. Pathophysiology of cerebral oedema: ammonia crosses BBB - astrocytic glutamine synthetase - glutamine accumulation - astrocyte swelling (cytotoxic oedema) - raised ICP - tonsillar herniation (1 cause of death). Management: N-acetylcysteine (NAC) for ALL causes (Lee 2009 showed transplant-free survival benefit beyond paracetamol), supportive care for complications, and urgent liver transplant assessment using King's College Criteria. Lactate is a key prognostic marker (early >3.5 mmol/L or persistent elevation predicts poor outcome). Do NOT routinely correct INR with FFP — it is a liver function marker, not a bleeding-risk indicator (rebalanced haemostasis).