From the Guidelines
Elevated liver enzymes are most commonly caused by non-alcoholic fatty liver disease (NAFLD), alcohol consumption, viral hepatitis, and certain medications, with the specific causes often identifiable through patterns of enzyme elevation, such as AST to ALT ratio, and clinical context 1. The causes of elevated liver enzymes can be broadly categorized into hepatocellular and cholestatic patterns. Hepatocellular injury, which is associated with elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), can result from various factors including:
- Viral hepatitis (such as hepatitis A, B, and C)
- Alcohol consumption, leading to alcohol-induced fatty liver disease
- Non-alcoholic fatty liver disease (NAFLD), which is closely linked to metabolic syndrome and insulin resistance
- Certain medications, such as acetaminophen, statins, antibiotics, and anti-seizure drugs
- Autoimmune hepatitis
- Other less common causes like alpha1-antitrypsin deficiency, Wilson disease, and hemochromatosis
On the other hand, cholestatic patterns, characterized by elevated alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT), can be due to:
- Obstructive conditions, such as gallstones or bile duct obstruction
- Intrahepatic or extrahepatic cholestasis
- Primary biliary cholangitis or primary sclerosing cholangitis
- Drug-induced cholestasis
It's crucial to note that the pattern and degree of liver enzyme elevation can provide significant clues about the underlying cause. For instance, an AST to ALT ratio greater than 2 is often suggestive of alcohol-related liver damage, while a ratio less than 1 may indicate metabolic disease-related fatty liver 1. Similarly, concomitantly elevated GGT can help confirm that an elevated ALP originates from the liver, indicating cholestasis 1.
Given the complexity and the variety of potential causes, consultation with a healthcare provider is essential for proper evaluation and treatment of elevated liver enzymes, as it allows for the identification of the underlying cause and the implementation of targeted interventions to improve liver health and prevent progression to more severe liver disease 1.
From the Research
Causes of Elevated Liver Enzymes
Elevated liver enzymes can be caused by various factors, including:
- Nonalcoholic fatty liver disease (NAFLD) 2, which is the most common cause of elevated liver enzymes in patients of developed countries
- Drug-induced liver injury (DILI) 3, 4, which can be caused by various medications, including antimicrobial and central nervous system agents
- Alcoholic liver disease (ALD) 5, which can cause elevated liver enzymes due to significant alcohol intake
- Psoriasis 6, which can increase the risk of liver abnormalities, including NAFLD and drug-induced hepatitis
- Other factors, such as obesity, diabetes mellitus, alcohol consumption, hepatotoxic medications, dyslipidemia, psoriatic arthritis, and infectious hepatitis 6
Specific Causes
Some specific causes of elevated liver enzymes include:
- Nonalcoholic steatohepatitis (NASH) 2, which can reduce survival and increase the risk of liver-related complications
- Antituberculosis drugs 3, which can cause DILI in some patients
- Herbal therapy 6, which can cause toxic hepatitis and cirrhosis in rare cases
- Amiodarone and methotrexate 4, which can cause chronic DILI and cirrhosis in some patients
Clinical Presentation
The clinical presentation of elevated liver enzymes can vary depending on the underlying cause, but may include: