Differential Diagnosis for a 70-year-old Man with Steadily Increasing AST Levels

Single Most Likely Diagnosis

• Non-alcoholic fatty liver disease (NAFLD): This condition is common in older adults and can cause a gradual increase in AST levels, even with normal other liver functions. The steady increase in AST levels over time suggests a chronic process, which is consistent with NAFLD.

Other Likely Diagnoses

• Alcoholic liver disease: Although not explicitly mentioned, alcohol use is a common cause of elevated AST levels in older adults. The pattern of AST elevation could be consistent with alcoholic liver disease, especially if the patient has a history of alcohol consumption.
• Medication-induced liver injury: Many medications can cause liver enzyme elevations, and older adults often take multiple medications, increasing the risk of drug-induced liver injury. The gradual increase in AST levels could be due to a medication effect.
• Chronic viral hepatitis: Hepatitis B or C can cause chronic liver disease, leading to elevated AST levels. Although other liver functions are normal, chronic viral hepatitis can have a variable presentation.

Do Not Miss Diagnoses

• Hepatocellular carcinoma: Although less likely, hepatocellular carcinoma can cause elevated AST levels, and it is essential to consider this diagnosis, especially in older adults. Missing this diagnosis could have severe consequences.
• Budd-Chiari syndrome: This rare condition, caused by hepatic vein thrombosis, can lead to elevated AST levels and normal other liver functions. It is crucial to consider this diagnosis to avoid missing a potentially life-threatening condition.
• Wilson's disease: Although rare, Wilson's disease can cause liver enzyme elevations, and it is essential to consider this diagnosis to avoid missing a treatable condition.

Rare Diagnoses

• Alpha-1 antitrypsin deficiency: This genetic disorder can cause liver disease, leading to elevated AST levels. Although rare, it is essential to consider this diagnosis, especially if other causes are ruled out.
• Hemochromatosis: This genetic disorder can cause iron overload, leading to liver disease and elevated AST levels. Although rare, it is essential to consider this diagnosis, especially if other causes are ruled out.
• Autoimmune hepatitis: This condition can cause liver enzyme elevations, and although rare, it is essential to consider this diagnosis to avoid missing a treatable condition.