Differential Diagnosis for ANA Positive, Elevated LFT, and Total Bilirubin

Single Most Likely Diagnosis

• Autoimmune Hepatitis (AIH): This condition is characterized by elevated liver function tests (LFTs), positive antinuclear antibodies (ANA), and often elevated total bilirubin. The presence of ANA is a hallmark, although not exclusive to AIH, making it a strong candidate given the combination of findings.

Other Likely Diagnoses

• Primary Biliary Cholangitis (PBC): Previously known as primary biliary cirrhosis, PBC can present with elevated LFTs, particularly alkaline phosphatase, and is often associated with positive ANA. Although total bilirubin elevation is less common in early stages, it can occur as the disease progresses.
• Systemic Lupus Erythematosus (SLE): SLE is a multisystem autoimmune disease that can affect the liver, leading to elevated LFTs and, in some cases, elevated bilirubin. The presence of ANA is a diagnostic criterion for SLE, making it a plausible diagnosis.
• Drug-Induced Liver Injury (DILI): Certain medications can cause liver injury, leading to elevated LFTs and bilirubin. While ANA positivity is not a direct result of DILI, some drugs can induce autoantibody production, making this a consideration, especially with a relevant medication history.

Do Not Miss Diagnoses

• Wilson's Disease: Although less common, Wilson's disease is a genetic disorder leading to copper accumulation in the liver, which can cause liver dysfunction, elevated LFTs, and sometimes elevated bilirubin. ANA can be positive in some cases. Missing this diagnosis can lead to severe liver damage and other systemic complications.
• Acute Viral Hepatitis: Certain viral hepatitis infections (e.g., hepatitis A, B, or C) can present with elevated LFTs and bilirubin. While ANA is not typically associated with viral hepatitis, it's crucial to rule out these infections due to their potential for severe outcomes and the need for specific antiviral treatments.

Rare Diagnoses

• Overlap Syndrome: This refers to conditions where features of AIH coexist with those of other liver diseases, such as PBC or primary sclerosing cholangitis. The presentation can be complex, with elevated LFTs, bilirubin, and positive ANA, among other findings.
• Budd-Chiari Syndrome: A rare condition caused by hepatic vein thrombosis, leading to liver dysfunction, which can include elevated LFTs and bilirubin. ANA positivity might be seen in some cases, particularly if there's an underlying autoimmune disorder contributing to thrombosis.