Hepatotoxins

Acute Liver Failure

ALF is defined as the onset of coagulopathy and any degree of hepatic encephalopathy within 26 weeks of the appearance of symptoms in the absence of underlying liver disease. It can be stratified into an acute (<4 weeks) or subacute (4 weeks to 6 months) presentation. Exceptions include Wilson's disease, chronic hepatitis B virus (HBV) infection, or autoimmune hepatitis (AIH), which may present with ALF despite the presence of chronic liver disease or cirrhosis.

Acute liver failure (ALF) is an uncommon condition in which the rapid deterioration of liver function results in coagulopathy and alteration in the mental status of a previously healthy individual. Acute liver failure often affects young people and carries a very high mortality. The term acute liver failure is used to describe the development of coagulopathy, usually an international normalized ratio (INR) of greater than 1.5, and any degree of mental alteration (encephalopathy) in a patient without preexisting cirrhosis  and with an illness of less than 26 weeks' duration.

Acute liver failure is a broad term and encompasses both fulminant hepatic failure (FHF) and subfulminant hepatic failure (or late-onset hepatic failure). Fulminant hepatic failure is generally used to describe the development of encephalopathy within 8 weeks of the onset of symptoms in a patient with a previously healthy liver. Subfulminant hepatic failure is reserved for patients with liver disease for up to 26 weeks before the development of hepatic encephalopathy.

When damage to the hepatic parenchyma is so severe that the liver is no longer able to meet the metabolic requirements of the body, the syndrome of ALF develops. The outcome is characterized by coagulopathy, hepatic encephalopathy, often associated with cerebral edema, hemodynamic changes, electrolyte disturbance, and renal failure.