Acute Liver Failure

Acute liver failure (ALF) is an uncommon condition characterized by the rapid onset of liver dysfunction within 26 weeks in individuals without preexisting liver disease or cirrhosis, accompanied by altered mental status (encephalopathy) and coagulopathy, resulting in an INR ≥1.5. Some conditions are also among the differential diagnoses that may cause ALF despite not strictly meeting this definition, including autoimmune hepatitis, Budd-Chiari syndrome, and Wilson disease, which may present acutely even in patients with preexisting liver scarring. According to the O'Grady classification system, ALF can be categorized into hyperacute (<7 days), acute (1-4 weeks), and subacute forms (>4 weeks), depending on the rate of encephalopathy development. Hyperacute ALF, also referred to as fulminant hepatic failure, which is most commonly associated with viral hepatitis A, E, acetaminophen toxicity, or ischemic liver injury, carries a higher risk of cerebral edema but has a better prognosis if treated without a liver transplant. Although cerebral edema is less common in the slower-progressing forms, the prognosis is generally poorer without a transplant. The interval between the onset of jaundice and the development of encephalopathy is a critical prognostic indicator.  Accurate diagnosis is crucial for distinguishing between acute and acute-on-chronic liver failure. Laboratory tests, imaging, and a detailed patient history, including medication use, alcohol consumption, and risk factors for viral hepatitis, are critical for this differentiation. Acetaminophen toxicity accounts for most cases of ALF in the West. Acute viral hepatitis (AVH) is the most common cause of ALF in the Asia-Pacific region due to the continued widespread transmission of hepatitis A and E. For instance, 40% of ALF cases in Japan are associated with HBV, while approximately 50% of cases in India are a result of acute hepatitis HEV. Specific diagnostic tests for viral hepatitis, autoimmune diseases, and potential acetaminophen toxicity are essential for identifying the cause of ALF to avoid misdiagnoses or diagnostic delays. Most ALF patients with AVH will present with fatigue, fever, nausea, and vomiting before clinical features of more severe liver damage (eg, jaundice) become evident. Though ALF has high morbidity and mortality, its overall survival has improved through intensive care management and emergency liver transplantation advancements. A high index of suspicion, early referral to a specialist liver transplantation center, and adequate supportive management remain the cornerstone for the management of ALF. A better understanding and knowledge of the pathophysiology of liver injury and the management of ALF will help improve outcomes.