From the Guidelines
Elevated ALT and AST levels indicate potential liver damage or disease, and it is crucial to consult a healthcare provider for proper evaluation and diagnosis, as the underlying cause can significantly impact treatment and outcome. The most recent and highest quality study, 1, provides guidance on the detection, assessment, and management of suspected drug-induced liver injury, which can be applied to the interpretation of elevated liver enzymes. According to this study, the severity of ALT and AST elevation can be classified as mild, moderate, or severe, with mild elevations being less than 3 times the upper reference limit, moderate elevations being 3-5 times the upper reference limit, and severe elevations being greater than 5 times the upper reference limit.
Some key points to consider when evaluating elevated ALT and AST levels include:
- Common causes of elevated liver enzymes, such as viral hepatitis, alcohol consumption, fatty liver disease, certain medications, and autoimmune conditions, as noted in 1 and 1
- The importance of interpreting the pattern of elevation, including the AST:ALT ratio, to determine the likely cause of liver damage, as discussed in 1
- The need for additional tests, such as a complete liver panel, hepatitis screening, and imaging studies, to determine the underlying cause of elevated liver enzymes, as recommended in 1 and 1
- The importance of avoiding alcohol, reviewing medications with a doctor, maintaining a healthy diet, and staying hydrated while waiting for medical evaluation, as suggested in the example answers
In terms of treatment, the approach will depend entirely on the underlying cause of the elevated liver enzymes. For example:
- Viral hepatitis may require antiviral medications
- Fatty liver disease may respond to lifestyle changes
- Medication-induced elevations may resolve when the medication is stopped
- Other causes, such as autoimmune conditions, may require specific treatments, such as immunosuppressive medications
Overall, it is essential to consult a healthcare provider for proper evaluation and diagnosis of elevated ALT and AST levels, as prompt and appropriate treatment can significantly impact morbidity, mortality, and quality of life.
From the Research
Causes of Elevated ALT and AST
- Elevated serum levels of transaminases (AST and ALT) usually indicate hepatocellular damage 2
- ALT elevations can also be of extrahepatic origin, such as muscle damage 2, 3
- Chronic alcohol consumption, drugs, non-alcoholic steatohepatitis (NASH), and chronic viral hepatitis are common causes associated with raised ALT and AST 4
- Non-hepatic causes of raised ALT and AST include polymyositis, acute muscle injury, acute myocardial infarction, and hypothyroidism 4, 3
Evaluation of Elevated ALT and AST
- The initial evaluation should include an assessment for metabolic syndrome and insulin resistance, a complete blood count with platelets, measurement of serum albumin, iron, total iron-binding capacity, and ferritin, and hepatitis C antibody and hepatitis B surface antigen testing 5, 6
- The nonalcoholic fatty liver disease fibrosis score and the alcoholic liver disease/nonalcoholic fatty liver disease index can be helpful in the evaluation of mildly elevated transaminase levels 5
- If testing for common causes is consistent with nonalcoholic fatty liver disease and is otherwise unremarkable, a trial of lifestyle modification is appropriate 5, 6
- If the elevation persists, hepatic ultrasonography and further testing for uncommon causes should be considered 5, 6
Common Causes of Elevated ALT and AST
- Nonalcoholic fatty liver disease is the most common cause of mildly elevated liver transaminase levels, affecting up to 30 percent of the population 5, 6
- Alcoholic liver disease, medication-associated liver injury, viral hepatitis (hepatitis B and C), and hemochromatosis are other common causes 5, 6
- Less common causes include α(1)-antitrypsin deficiency, autoimmune hepatitis, and Wilson disease 5, 6