I have an obese adolescent in my practice and the patient has an elevated ALT much higher than the AST. What should I do now?
This is most likely non-alcoholic fatty liver disease (NAFLD). This occurs in upwards of 20-30% of obese individuals. Typically the ALT is much higher than the AST. It is more common in males and more common in individuals who have signs of insulin resistance. The first step would be a physical exam for signs of chronic liver disease (splenomegaly or jaundice) which would be uncommon in non-alcoholic fatty liver disease. In an otherwise well, obese individual, with an otherwise normal physical exam, the first step would be an attempt at weight loss. If weight loss is successful, the elevated ALT will often improve. If the elevated ALT persists despite weight loss, or if weight loss is unsuccessful, screening should be considered to exclude chronic viral hepatitis (HBsAg and anti-HCV antibody), alpha-1 antitrypsin deficiency (alpha-1 antitrypsin level), Wilson’s disease (ceruloplasmin) and autoimmune hepatitis (ANA, anti-smooth muscle antibody, and anti-liver, kidney, microsomal antibody). Non-alcoholic fatty liver disease can progress to significant fibrotic liver disease. However, at this point, the major therapy is weight loss. There are ongoing studies of therapies such as vitamin E and metformin at the present time.