What are the causes of elevated Aspartate Aminotransferase (AST)?

From the Guidelines

Elevated AST levels are primarily caused by liver diseases, such as hepatitis, fatty liver disease, and alcoholic liver disease, as well as non-hepatic causes like heart problems, muscle damage, and certain medications, as indicated by the most recent study 1. The causes of elevated Aspartate Aminotransferase (AST) can be broadly categorized into hepatic and non-hepatic causes. Hepatic causes include liver diseases such as hepatitis, fatty liver disease, and alcoholic liver disease, which can lead to hepatocellular injury and the release of AST into the serum 1. Non-hepatic causes, on the other hand, include heart problems, muscle damage, and certain medications, which can also lead to elevated AST levels 1.

Some key points to consider when evaluating elevated AST levels include:

• The severity of the elevation, with mild, moderate, and severe elevations classified as <5 times, 5-10 times, and >10 times the upper reference limit, respectively 1
• The presence of other liver function test abnormalities, such as elevated ALT and ALP, which can help differentiate between hepatic and non-hepatic causes 1
• The patient's medical history, including any pre-existing liver disease, heart problems, or muscle damage, which can increase the risk of elevated AST levels 1
• The use of certain medications, such as statins, which can cause muscle injury and elevated AST levels 1

It is essential to consult with a healthcare provider for proper evaluation and management of elevated AST levels, as the underlying cause needs to be identified and addressed to prevent further liver damage and improve patient outcomes 1. In terms of management, treatment depends entirely on the identified cause of the elevated AST levels. For example, stopping alcohol consumption may be necessary for alcoholic liver disease, while weight loss may be recommended for fatty liver disease 1. Medication adjustments may also be necessary if the elevation is drug-induced 1.

Overall, elevated AST levels require prompt medical attention to determine the underlying cause and initiate appropriate treatment to prevent further liver damage and improve patient outcomes.

From the FDA Drug Label

Reactivation of HBV replication may be accompanied by hepatitis, i.e., increases in aminotransferase levels The cause of elevated Aspartate Aminotransferase (AST) mentioned in the label is hepatitis due to HBV reactivation 2.

• HBV reactivation can lead to increases in aminotransferase levels, including AST.
• This can occur in patients with HBV infection, including those who are HBsAg positive or have serologic evidence of resolved HBV infection.

From the Research

Causes of Elevated Aspartate Aminotransferase (AST)

• Elevated AST levels can be caused by various factors, including liver damage, cardiac and skeletal muscle damage, and erythrocyte damage 3
• Macro-aspartate aminotransferase (macro-AST) is a rare cause of elevated AST activity in serum, which can lead to diagnostic confusion in clinical conditions associated with chronic liver disease 4
• Non-hepatic causes of raised AST include polymyositis, acute muscle injury, acute myocardial infarction, and hypothyroidism 5
• Chronic alcohol consumption, drugs, non-alcoholic steatohepatitis (NASH), and chronic viral hepatitis are common causes associated with raised AST and ALT levels 5
• Ischemic hepatitis, acute viral hepatitis, and drug-induced liver injury (DILI) are also potential causes of severe acute liver injury, which can result in elevated AST levels 6

Specific Conditions Associated with Elevated AST

• Non-alcoholic fatty liver disease (NAFLD) can be associated with elevated AST levels, as seen in a case report where polyethylene glycol precipitation confirmed the presence of macro-AST 4
• Chronic hepatitis, particularly of viral etiology, can also lead to elevated AST levels, which can be reduced with treatment using ursodeoxycholic acid (UDCA) 7
• Acute myocardial infarction can cause elevated AST levels, as seen in a case report of a 79-year-old woman who developed elevated serum transaminases shortly after having a myocardial infarction 3