How can I differentiate between alcoholic and non-alcoholic liver disease in patients presenting with elevated liver enzymes?

To differentiate between alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) in patients presenting with elevated liver enzymes, the initial and crucial step is to take a comprehensive alcohol history to rule out alcohol-related liver disease ².

It is important to note that routine liver blood tests should not be used to rule out NAFLD, to assess for advanced liver fibrosis in people with NAFLD, or to rule out cirrhosis ¹,²,³. Liver function tests (LFTs) may also be unreliable in monitoring NAFLD disease progression ¹.

Key differentiating factors and diagnostic approaches include:

• Alcohol History: A detailed alcohol history is essential to distinguish between the two conditions ².
• Risk Factors:
  • NAFLD is more common in people who have type 2 diabetes or metabolic syndrome ². People who are overweight or obese are also at increased risk of progressive NAFLD ¹.
  • There is an increased risk of cirrhosis in people who misuse alcohol ³. Obesity and type 2 diabetes are also risk factors for cirrhosis, which can be a complication of NAFLD ³.
• Diagnostic Assessment:
  • For suspected NAFLD, if there is uncertainty about the diagnosis or signs of advanced liver disease, referral to a hepatology specialist is indicated ¹. Non-invasive tests like the enhanced liver fibrosis (ELF) test can be considered to test for advanced liver fibrosis in people diagnosed with NAFLD ². An ELF score of 10.51 or above, along with NAFLD, indicates advanced liver fibrosis ². Transient elastography or acoustic radiation force impulse imaging can be offered to diagnose cirrhosis in people with NAFLD and advanced liver fibrosis ³.
  • For suspected ALD, transient elastography should be offered to diagnose cirrhosis for men who drink over 50 units of alcohol per week and have done so for several months, or women who drink over 35 units per week for several months, or people diagnosed with alcohol-related liver disease ³.
  • Liver biopsy may be needed to confirm the diagnosis of non-alcoholic steatohepatitis (NASH) or cirrhosis, or to exclude other liver diseases, especially when non-invasive tests are indeterminate or discordant ¹,³.
• Referral: People diagnosed with advanced liver fibrosis or cirrhosis should be referred to a relevant specialist in hepatology ²,³.