What are the diagnostic criteria for acute liver failure?

From the Guidelines

Acute liver failure is diagnosed when a patient without pre-existing liver disease develops severe liver dysfunction characterized by a prothrombin time (PT) ratio less than 50% and any degree of hepatic encephalopathy within 26 weeks of the first symptoms, as defined by the most recent criteria 1. The diagnosis of acute liver failure requires a comprehensive approach, including laboratory testing and clinical evaluation. Key diagnostic criteria include:

• A PT ratio less than 50%, which defines severe acute liver failure 1
• Any degree of hepatic encephalopathy, which is a key prognostic indicator for liver transplantation 1
• Laboratory testing, such as liver function tests showing markedly elevated aminotransferases (AST, ALT), elevated bilirubin levels, and prolonged prothrombin time or INR
• Clinical features, including jaundice, confusion, asterixis, and in severe cases, cerebral edema
• Additional diagnostic criteria, such as hypoglycemia, metabolic acidosis, elevated lactate, and renal dysfunction Imaging studies, like ultrasound or CT scan, can help exclude chronic liver disease and assess liver size. The etiology of acute liver failure must be determined through viral hepatitis serologies, toxicology screens, autoimmune markers, and medication history, with acetaminophen overdose being the most common cause in developed countries 1. The King’s College criteria and Clichy–Villejuif criteria are used to select candidates for liver transplantation, with factors such as pH, prothrombin time, creatinine level, and hepatic encephalopathy grade being considered 1. Early diagnosis and intensive monitoring are crucial, as mortality rates exceed 80% in severe cases without transplantation.

From the Research

Diagnostic Criteria for Acute Liver Failure

The diagnostic criteria for acute liver failure (ALF) include:

• Coagulopathy, defined as an International Normalized Ratio (INR) ≥ 1.5 2, 3, 4
• Hepatic encephalopathy 2, 3, 4, 5
• Severe liver damage in patients without pre-existing liver disease 2, 3, 4
• Marked transaminases elevation and detoxification disorder (jaundice) 4
• Exclusion of underlying chronic liver disease and secondary causes like sepsis or cardiogenic shock 4

Key Characteristics of Acute Liver Failure

Some key characteristics of ALF include:

• A rare, potentially fatal complication of severe hepatic illness resulting from various causes 5
• A high mortality rate unless liver transplantation is performed 2, 6
• The central and most important clinical event in ALF is the occurrence of hepatic encephalopathy (HE) and cerebral edema, which is responsible for most of the fatalities in this serious clinical syndrome 5
• The pathogenesis of encephalopathy and cerebral edema in ALF is unique and multifactorial, with ammonia playing a central role 5

Causes and Treatment of Acute Liver Failure

The causes of ALF include:

• Paracetamol and warfarin toxicity 4
• Autoimmune and viral (mainly hepatitis B and E) hepatitis 4
• Herbal and dietary supplements 4
• Viral hepatitis (especially hepatitis E), tropical infections (eg, dengue), traditional medicines, and drugs (especially anti-tuberculosis drugs) in low-income and middle-income countries 6 Treatment options for ALF include:
• Liver transplant, which is the only effective therapy that has been identified to be of promise in those with poor prognostic factors 5
• Aggressive intensive medical management, which has been documented to salvage a substantial proportion of patients 5