Elevated AST (Aspartate Aminotransferase) and ALT (Alanine Aminotransferase) levels?

From the Guidelines

Elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels indicate liver injury, and management involves identifying and addressing the underlying cause [ 1 ].

Causes of Elevated AST and ALT

• Viral hepatitis: Patients with elevated AST/ALT levels should be evaluated for viral hepatitis, such as hepatitis B and C [ 1 ].
• Autoimmune hepatitis: Autoimmune hepatitis is another potential cause of elevated AST/ALT levels [ 1 ].
• Drug-induced liver injury: Discontinuation of potentially hepatotoxic medications such as acetaminophen, statins, and certain antibiotics is recommended [ 1 ].

Evaluation and Management

• Initial evaluation: The initial evaluation of abnormal liver tests includes a detailed history, inventory of medications, and a physical examination [ 1 ].
• Noninvasive serologic tests: Common hepatic diseases should be excluded with noninvasive serologic tests [ 1 ].
• Treatment: Treatment with ursodeoxycholic acid (UDCA) at a dose of 13-15 mg/kg/day for 6-12 months may be considered for patients with chronic liver disease [ 1 ], while patients with acute liver injury may require hospitalization and supportive care, including administration of N-acetylcysteine (NAC) at a dose of 150 mg/kg/day for 5-7 days.

Key Points

• Elevated AST and ALT levels indicate liver injury and require further evaluation to determine the underlying cause.
• Discontinuation of potentially hepatotoxic medications and treatment with UDCA or NAC may be necessary.
• A detailed history, physical examination, and noninvasive serologic tests are essential in the initial evaluation of abnormal liver tests.

From the FDA Drug Label

Ursodiol therapy has not been associated with liver damage. ... Abnormalities in liver enzymes have not been associated with Ursodiol therapy and, in fact, Ursodiol has been shown to decrease liver enzyme levels in liver disease. However, patients given Ursodiol should have SGOT (AST) and SGPT (ALT) measured at the initiation of therapy and thereafter as indicated by the particular clinical circumstances

Elevated AST and ALT levels are not typically associated with ursodeoxycholic acid (Ursodiol) therapy. In fact, Ursodiol has been shown to decrease liver enzyme levels in liver disease. However, it is recommended to monitor AST and ALT levels in patients taking Ursodiol as a precautionary measure 2.

From the Research

Causes of Elevated AST and ALT Levels

• Elevated serum amino-transferase levels may be associated with liver injury, and testing for aspartate aminotransferase (AST) or alanine aminotransferase (ALT) is part of many routine screening approaches 3
• The most common causes of elevated transaminase levels are nonalcoholic fatty liver disease and alcoholic liver disease 4
• Other causes of elevated AST and ALT levels include:
  • Chronic viral hepatitis, such as hepatitis B and C 5, 4
  • Drug-induced liver injury, such as acetaminophen toxicity 6
  • Hereditary hemochromatosis, alpha1-antitrypsin deficiency, autoimmune hepatitis, and Wilson disease 4
  • Extrahepatic sources, such as thyroid disorders, celiac sprue, hemolysis, and muscle disorders 4
  • Ischemic hepatitis, acute viral hepatitis, and polymyositis 6, 5

Evaluation and Diagnosis

• 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 4
• 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 4
• If testing for common causes is consistent with nonalcoholic fatty liver disease and is otherwise unremarkable, a trial of lifestyle modification is appropriate 4
• If the elevation persists, hepatic ultrasonography and further testing for uncommon causes should be considered 4

Prognosis and Disease Severity

• The aspartate aminotransferase-alanine aminotransferase ratio (AST/ALT ratio) has been used to noninvasively assess the severity of disease in patients with chronic liver disease (CLD) 7
• The AST/ALT ratio is correlated with both histologic stage and clinical evaluation, and progressive liver functional impairment is reflected by an increase in the AST/ALT ratio 7
• The AST/ALT ratio provides medium-term prognostic information that is no different from that provided by established prognostic scores 7