Differential Diagnosis for Elevated AST and ALT with Normal Ammonia
Single Most Likely Diagnosis
- Viral Hepatitis: The elevated AST and ALT levels, with ALT being higher than AST, are consistent with viral hepatitis, such as hepatitis A, B, or C. The normal ammonia level does not suggest severe liver dysfunction or encephalopathy at this stage.
Other Likely Diagnoses
- Alcoholic Liver Disease: Although the AST:ALT ratio is not provided, alcoholic liver disease can cause elevations in both enzymes. However, the ratio is typically >2 in alcoholic liver disease, and the patient's history would be crucial in making this diagnosis.
- Non-Alcoholic Fatty Liver Disease (NAFLD): This condition can cause mild to moderate elevations in liver enzymes, especially ALT. The diagnosis would depend on the patient's metabolic profile, imaging studies, and the absence of other liver diseases.
- Drug-Induced Liver Injury: Various medications and drugs can cause elevations in liver enzymes. A thorough medication history is essential to consider this diagnosis.
Do Not Miss Diagnoses
- Acute Liver Ischemia or Infarction: Although less common, acute liver ischemia or infarction can present with rapid elevations in liver enzymes. This condition is critical and requires immediate attention.
- Wilson's Disease: This rare genetic disorder can cause liver enzyme elevations and would be particularly concerning in younger patients. Normal ammonia levels do not rule out Wilson's disease, as it can present with a wide range of liver function abnormalities.
- Budd-Chiari Syndrome: This condition, caused by hepatic vein thrombosis, can lead to liver enzyme elevations and requires prompt diagnosis and treatment to prevent severe complications.
Rare Diagnoses
- Autoimmune Hepatitis: This condition can cause significant elevations in liver enzymes and would be considered if other causes are ruled out, especially in the presence of autoimmune markers.
- Alpha-1 Antitrypsin Deficiency: A genetic disorder that can cause liver disease, presenting with elevated liver enzymes. It is less common and typically considered when other diagnoses are excluded.
- Hemochromatosis: A genetic disorder leading to iron overload, which can cause liver enzyme elevations among other symptoms. It is less likely but should be considered in the differential diagnosis, especially if other signs of iron overload are present.