Diseases of the liver: Acute liver disease
The most basic classification of liver disease is as acute and chronic. The definition of acute liver disease (such as acute hepatitis and acute liver failure [ALF]) is based on duration, with the history of the disease does not exceed six months. Diseases of longer duration are classified as chronic (such as chronic viral hepatitis, cirrhosis). An additional term, “acute-on-chronic” is used to describe a sudden clinical complication in a previously stable patient with chronic liver disease, such as bleeding from oesophageal varices in a patient with cirrhosis.
Acute viral hepatitis and drug reactions account for the majority of cases of acute liver disease. Hepatitis A and B are the commonest causes of viral hepatitis in Europe and hepatitis E is common in India. Hepatitis C is not usually recognised as an acute infection because it rarely causes jaundice at this stage.
Idiosyncratic reactions to recreational drugs such as “ecstasy”, or therapeutic drugs may occur. Such reactions (eg, cholestasis, hepatitis, ALF) are relatively common with antituberculous drugs and non-steroidal anti-inflammatory drugs, but also occur less frequently with some other drugs (see Panel 1, p132). Paracetamol toxicity is an example of a semi-quantitative reaction (the risk of a reaction increases with the dose but this is neither universal nor linear) and it is often used intentionally in suicide attempts.
Patients with acute hepatitis usually present with jaundice and this can last for several weeks. Spontaneous recovery is the norm and there is no specific treatment.The severity of the liver damage is most accurately assessed by measuring coagulation activity (international normalised ratio [INR], prothrombin time, Factor V). Once coagulation becomes abnormal, the patient is at risk of developing acute liver failure.
Acute liver failure
Acute liver failure was originally described as the appearance of hepatic encephalopathy associated with severe liver dysfunction, coagulopathy and jaundice, within a time frame of six months following the onset of symptoms.1 Since then, the classification of ALF has been revised to take into account the heterogeneous nature of the syndrome with regards to aetiology, frequency of complications, and outcome.The need to update and re-define the syndrome has been, in part, driven by the requirement to identify patients who would be appropriate candidates for liver transplantation.
A recent classification has defined the syndrome by proposing three classes: hyperacute, acute and subacute liver failure (Table 1, p132).
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Citation: Hospital Pharmacist URI: 10975474
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