Differentials
Severe acute hepatitis
SIGNS / SYMPTOMS
Patients may present with jaundice and coagulopathy. However, this would not be considered ALF in the absence of hepatic encephalopathy. Severe acute hepatitis should be followed very closely as this may potentially develop into ALF or subacute liver failure, depending on the time course and development of hepatic encephalopathy.
INVESTIGATIONS
Absence of hepatic encephalopathy. According to the West Haven Criteria, hepatic encephalopathy can be categorised into 4 grades based on severity:[49][69][70]
Grade 1: subtly impaired awareness, sleep alterations, shortened attention span, impaired addition or subtraction, heightened mood or anxiety, oriented in time and space.
Grade 2: lethargy or apathy, disorientation for time, obvious personality change, inappropriate behaviour, dyspraxia, asterixis.
Grade 3: somnolence to semi-stupor, responsive to vocal stimuli, marked confusion, gross disorientation (disoriented in time and space), bizarre behaviour. Physical findings may include hyper-reflexia, nystagmus, clonus, and rigidity.
Grade 4: coma.
Cholestasis
SIGNS / SYMPTOMS
Jaundice may result from intra- or extrahepatic biliary obstruction as well as from intrahepatic cholestasis due to conditions such as drug-induced liver injury or a chronic cholestatic liver disease. In the setting of an acute biliary obstruction, a patient may present with shock associated with cholangitis. Key features that distinguish these presentations from ALF include absence of coagulopathy and of hepatic encephalopathy, both of which are present during ALF.
INVESTIGATIONS
Normal prothrombin time (PT)/INR, absence of hepatic encephalopathy (according to the West Haven Criteria as mentioned above).[49][69][70] In the presence of coagulopathy associated with cholestatic disorders and vitamin K deficiency, administration of subcutaneous vitamin K would improve PT/INR and may also be considered as a differentiating test.
Haemolysis
SIGNS / SYMPTOMS
May present with jaundice characterised by an elevated unconjugated (indirect) serum bilirubin.
Typically occurs in the absence of liver dysfunction; therefore, coagulopathy and hepatic encephalopathy would not be present. Exceptions to this include ALF secondary to Wilson's disease, which may be associated with a Coombs-negative haemolytic anaemia.[43] ALF secondary to autoimmune hepatitis may coincide with an acute autoimmune haemolytic anaemia.[43][79] Sickle cell disease may also present acutely with jaundice, haemolysis, and liver dysfunction as a result of a sickle cell hepatopathy.[80]
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