From the Guidelines
In alcoholic liver disease, the typical pattern of transaminase elevation is characterized by an AST to ALT ratio greater than 1.5, with AST levels usually ranging from 50-200 IU/mL and ALT levels typically lower, rarely exceeding 400 IU/mL, as noted in the most recent and highest quality study 1.
Key Findings
- The AST/ALT ratio is a key marker in differentiating alcoholic liver disease from other causes of liver injury, with a ratio greater than 1.5 being suggestive of alcoholic hepatitis 1.
- AST levels are typically elevated, but rarely exceed 400 IU/mL, while ALT levels are usually lower, as observed in a large series of patients with histologically proven alcoholic hepatitis 1.
- The pattern of transaminase elevation is influenced by the amount and duration of alcohol consumption, with heavy drinking leading to increased AST activity and depletion of hepatic ALT 1.
Clinical Implications
- The diagnosis of alcoholic liver disease should be suspected in patients with a history of heavy alcohol consumption and elevated liver enzymes, particularly with an AST/ALT ratio greater than 1.5 1.
- Liver biopsy can be useful in confirming the diagnosis and assessing the extent of liver damage, but is not always necessary for diagnosis 1.
- Gamma-glutamyl transferase (GGT) is also frequently elevated in alcohol users, making it a useful marker for alcohol consumption, although its specificity decreases in advanced liver disease 1.
Management
- Management of alcoholic liver disease involves cessation of alcohol consumption, nutritional support, and treatment of complications such as ascites and encephalopathy 1.
- Early detection and intervention are critical in preventing progression to advanced liver disease and improving patient outcomes 1.
From the Research
Pattern of Transaminase Elevation in Alcoholic Liver Disease
- The ratio of aspartate transaminase (AST) to alanine transaminase (ALT) is frequently higher in alcoholic than in non-alcoholic liver diseases 2.
- Elevated serum levels of transaminases (AST and ALT) usually indicate hepatocellular damage, but ALT elevations can also be of extrahepatic origin (muscle) 2, 3.
- Aminotransferase levels are often unremarkable in patients with alcohol-related cirrhosis and bear no relationship to clinical events or outcomes 4.
Correlation of AST/ALT Ratio with Underlying Severity
- The AST/ALT ratio is a useful and reliable biochemical marker of liver injury due to alcohol, and its value correlates with the clinical severity of alcoholic liver disease 5.
- A higher value of AST/ALT ratio is indicative of more severe liver damage due to alcohol, with mean AST/ALT ratios of 3.03,2.28, and 1.68 in patients with Child's grade C, B, and A, respectively 5.
Role of Gut Microbiota in Alcoholic Liver Injury
- The gut microbiome plays a role in individual susceptibility to alcoholic liver injury, with certain species (e.g., Faecalibacterium prausnitzii and Roseburia hominis) having a protective effect against inflammatory liver damage 6.
- Ruminococcus gnavus is positively associated with ALT and AST levels and contributes to liver inflammation 6.