What is the differential diagnosis for elevated Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) with normal Alkaline Phosphatase (Alk Phos)?

Differential Diagnosis for Elevated AST and ALT with Normal Alk Phos

Single Most Likely Diagnosis

• Viral Hepatitis: This is the most common cause of elevated liver enzymes (AST and ALT) with normal alkaline phosphatase (Alk Phos). Viral hepatitis, such as hepatitis A, B, or C, typically presents with elevated transaminases and can be confirmed with serological tests.

Other Likely Diagnoses

• Alcoholic Liver Disease: Alcoholic liver disease can cause elevated AST and ALT, often with a ratio of AST:ALT > 2:1. Normal Alk Phos levels do not rule out this diagnosis.
• Non-Alcoholic Fatty Liver Disease (NAFLD): NAFLD is a common cause of elevated liver enzymes, especially in patients with obesity, diabetes, or metabolic syndrome. Alk Phos levels are often normal in NAFLD.
• Drug-Induced Liver Injury: Many medications can cause elevated liver enzymes, including over-the-counter medications like acetaminophen. A thorough medication history is essential to diagnose drug-induced liver injury.

Do Not Miss Diagnoses

• Acute Budd-Chiari Syndrome: This rare condition, caused by hepatic vein thrombosis, can present with rapidly progressive liver failure and elevated liver enzymes. Normal Alk Phos levels do not rule out this diagnosis, and it requires prompt recognition and treatment.
• Wilson's Disease: This genetic disorder can cause liver damage and elevated liver enzymes. Although rare, it is essential to consider Wilson's disease in young patients with unexplained liver enzyme elevations.

Rare Diagnoses

• Autoimmune Hepatitis: This chronic inflammatory liver disease can cause elevated liver enzymes, but it is less common than other diagnoses on this list.
• Alpha-1 Antitrypsin Deficiency: This genetic disorder can cause liver disease and elevated liver enzymes, but it is relatively rare and often presents in childhood.
• Hemochromatosis: This genetic disorder causes iron overload and can lead to liver damage and elevated liver enzymes. However, it is less common than other diagnoses on this list and often presents with other systemic symptoms.