From the Guidelines
Acute liver failure is diagnosed when a patient without pre-existing liver disease develops severe liver dysfunction characterized by coagulopathy and any degree of hepatic encephalopathy within 26 weeks of the first symptoms, as defined by the recent guidelines published in 2023 1. The diagnosis of acute liver failure (ALF) is crucial in determining the prognosis and guiding treatment decisions. According to the guidelines, ALF is defined by the occurrence of encephalopathy and hepatic synthetic dysfunction within 26 weeks of the first symptoms of liver disease in a patient without evidence of chronic liver disease 1. Some key points to consider in the diagnosis of ALF include:
- The presence of coagulopathy, typically indicated by an INR ≥1.5
- The presence of any degree of hepatic encephalopathy
- The absence of pre-existing liver disease
- The time frame of 26 weeks from the first symptoms of liver disease The King's College Criteria are widely accepted and used to determine the prognosis of ALF, with different criteria for acetaminophen and non-acetaminophen causes 1. It is essential to recognize ALF early, as mortality without transplantation can be exceedingly high, often exceeding 80% in severe cases, and liver transplantation remains the definitive treatment for many patients with ALF who do not show signs of spontaneous recovery 1.
From the Research
Definition and Diagnostic Criteria
- Acute liver failure (ALF) is defined as a clinical syndrome of rapid hepatocyte injury leading to liver failure manifested by coagulopathy and encephalopathy in the absence of pre-existing cirrhosis 2.
- The hallmark diagnostic features are a prolonged prothrombin time (ie, an international normalized ratio of prothrombin time of ≥1.5) and any degree of mental status alteration (HE) 2.
- ALF is characterized by the development of hepatic encephalopathy and coagulopathy within 26 weeks of the onset of acute liver disease 3, 4.
Prognostic Criteria
- Prognosis can be poor and patients should be referred to a liver transplantation center as soon as possible 5.
- Coagulopathy in ALF is a useful prognostic tool and a dynamic indicator of the hepatic function 4.
- Global assessments of coagulopathy via viscoelastic tests or thrombin generation assay can provide more nuanced insights into the hemostatic system in ALF 6.
Clinical Considerations
- The elevated international normalized ratio value in ALF is often misinterpreted as an increased hemorrhagic tendency, which can lead to inappropriate, prophylactic transfusions of blood products 6.
- Measures to improve the bleeding diathesis (fresh frozen plasma, cryoprecipitate, platelet transfusion) are recommended only in patients with clinically significant bleeding or before placement of invasive devices 3.
- Antifibrinolytic drugs are used in some cases, but often empirically, and the role of rFVIIa is still under debate 3.