From the Guidelines
Elevated liver enzymes are a significant indicator of potential liver damage or disease, and their clinical significance should be evaluated in the context of the individual patient's overall health and medical history, as suggested by the guidelines on the management of abnormal liver blood tests 1. The presence of elevated liver enzymes can be a sign of various liver conditions, including non-alcoholic fatty liver disease (NAFLD), liver fibrosis, or other necro-inflammatory diseases. According to the guidelines, liver blood tests, such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT), are frequently elevated in these conditions, but the degree of abnormality is not always related to the stage of progression from simple fatty liver to cirrhosis. Key points to consider when evaluating elevated liver enzymes:
- The clinical significance of elevated liver enzymes should be assessed in the context of the individual patient's medical history, symptoms, and other laboratory results.
- The guidelines recommend using a FIB-4 or NAFLD fibrosis score to determine the likelihood of liver fibrosis in patients with NAFLD or liver disease of unknown etiology 1.
- Elevated liver enzymes can be a sign of drug-induced liver injury, and discontinuation of the causal agent is usually the most effective treatment, as recommended by the consensus guidelines for detection, assessment, and management of suspected acute drug-induced liver injury during clinical trials in patients with nonalcoholic steatohepatitis 2.
- The management of elevated liver enzymes should prioritize the prevention of further liver damage and improvement of outcomes, as suggested by the guidelines on the management of abnormal liver blood tests 1. In terms of management, it is essential to discontinue any potentially hepatotoxic medications, monitor liver function tests closely, and provide supportive care to prevent further liver damage and improve outcomes. Additionally, the guidelines recommend considering the use of serum markers, such as ELF, and imaging modalities, such as ARFI elastography/FibroScan, to assess liver fibrosis and guide management decisions 1.
From the Research
Significance of Elevated Liver Enzymes
Elevated liver enzymes are a common finding in both symptomatic and asymptomatic patients, necessitating further evaluation to clarify the underlying disease 3. The significance of elevated liver enzymes can be understood by considering the different patterns of enzyme alteration, which can be classified into hepatocellular, cholestatic, and isolated hyperbilirubinemia 4, 3.
Patterns of Enzyme Alteration
- Hepatocellular pattern: characterized by a predominant increase in transaminase activities, reflecting a disturbance of hepatocellular integrity, which can be found in patients with viral hepatitis, genetic liver diseases, and drug-induced liver diseases 3.
- Cholestatic pattern: characterized by high serum alkaline phosphatase and γ-glutamyltranspeptidase activities, indicating cholestatic liver diseases, which can be further evaluated using ultrasound studies to discern intra- from extrahepatic cholestasis 3.
- Isolated hyperbilirubinemia: can be observed in patients with hemolytic anemias, Gilbert's syndrome, or other conditions affecting bilirubin metabolism 3.
Causes of Elevated Liver Enzymes
The causes of elevated liver enzymes can be diverse, including:
- Viral hepatitis 3, 5
- Genetic liver diseases, such as Wilson's disease or hemochromatosis 3
- Drug-induced liver diseases 3, 5
- Non-alcoholic fatty liver disease (NAFLD) 5
- Alcohol intake 5
- Hepatitis C virus infection 5
- Hepatotoxicity 6, 5
Evaluation and Management
The evaluation and management of elevated liver enzymes require a step-wise approach, considering the patient's clinical presentation, laboratory results, and imaging studies 4, 3, 7. A single-act office visit can be an efficient way to evaluate patients with elevated liver enzymes, allowing for a definitive diagnosis to be reached in most cases 5. In some cases, liver biopsy may be necessary to establish a diagnosis or to assess the extent of liver damage 6.