Differential Diagnosis for Elevated ALT, AST, and BUN

Single Most Likely Diagnosis

• Viral Hepatitis: This is a common cause of elevated liver enzymes (ALT and AST) and can also lead to elevated BUN due to dehydration or decreased hepatic function affecting urea synthesis and metabolism. The liver's role in detoxification and metabolism can be compromised, leading to an increase in BUN.

Other Likely Diagnoses

• Alcoholic Liver Disease: Alcohol abuse can lead to liver inflammation and damage, causing elevations in ALT and AST. BUN can be elevated due to poor dietary intake, dehydration, or the direct toxic effect of alcohol on the kidneys.
• Non-Alcoholic Fatty Liver Disease (NAFLD): This condition can cause elevations in liver enzymes due to liver inflammation and damage. Elevated BUN might be seen in more advanced cases where there is significant liver dysfunction or in the presence of comorbid conditions like diabetes or obesity that affect kidney function.
• Medication-Induced Liver Injury: Certain medications can cause liver damage, leading to elevated ALT and AST. BUN elevation might occur if the medication also has nephrotoxic effects or if the liver injury is severe enough to affect overall metabolic function.

Do Not Miss Diagnoses

• Acute Hepatic Failure: Although less common, acute hepatic failure can present with rapidly elevated liver enzymes and BUN due to the liver's critical role in detoxification, metabolism, and production of proteins necessary for blood clotting. Missing this diagnosis can be fatal.
• Budd-Chiari Syndrome: This rare condition involves hepatic vein thrombosis, which can lead to acute liver failure, presenting with elevated liver enzymes and potentially elevated BUN due to decreased liver function and possible renal vein thrombosis.
• Wilson's Disease: An inherited disorder that leads to copper accumulation in the liver, causing liver damage and potentially acute liver failure. It's crucial not to miss this diagnosis due to its treatable nature if caught early.

Rare Diagnoses

• Autoimmune Hepatitis: A chronic disease where the body's immune system attacks the liver, causing inflammation and damage. It can present with elevated liver enzymes and potentially elevated BUN if there's significant liver dysfunction.
• Alpha-1 Antitrypsin Deficiency: A genetic disorder that can cause liver disease and potentially lead to elevated liver enzymes and BUN in severe cases.
• Hemochromatosis: A genetic disorder leading to iron overload, which can cause liver damage and potentially result in elevated liver enzymes and BUN if there's significant liver or kidney involvement.