What is the significance of elevated Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) in a 21-year-old female with normal bilirubin, normal Alkaline Phosphatase (alk phos), and normal Complete Blood Count (CBC)?

Differential Diagnosis for Elevated AST and ALT in a 21-Year-Old Female

Single Most Likely Diagnosis

• Non-alcoholic fatty liver disease (NAFLD): This is a common cause of mild elevations in AST and ALT in young adults, especially with the rising prevalence of obesity and metabolic syndrome. The normal bilirubin and alkaline phosphatase levels support this diagnosis.

Other Likely Diagnoses

• Viral hepatitis: Although the patient's liver function tests are not markedly elevated, viral hepatitis (such as hepatitis A, B, or C) can cause mild elevations in AST and ALT. The normal bilirubin level does not rule out this diagnosis.
• Alcoholic liver disease: Although less likely in a 21-year-old female, alcoholic liver disease can cause elevations in AST and ALT. A thorough history of alcohol use is necessary to assess this possibility.
• Medication-induced liver injury: Various medications, including over-the-counter drugs and herbal supplements, can cause elevations in liver enzymes. A detailed medication history is essential to evaluate this possibility.

Do Not Miss Diagnoses

• Wilson's disease: This is a rare genetic disorder that can cause liver damage and elevations in AST and ALT. Although unlikely, it is essential to consider this diagnosis, as early treatment can prevent long-term liver damage and other complications.
• Autoimmune hepatitis: This condition can cause elevations in liver enzymes and may not always present with typical symptoms. A high index of suspicion is necessary to diagnose this condition, as prompt treatment can improve outcomes.
• Alpha-1 antitrypsin deficiency: This genetic disorder can cause liver disease and elevations in AST and ALT. Although rare, it is crucial to consider this diagnosis, as it may have significant implications for the patient's health and family screening.

Rare Diagnoses

• Hemochromatosis: This genetic disorder can cause iron overload and liver damage, leading to elevations in AST and ALT. Although rare, it is essential to consider this diagnosis, as early treatment can prevent long-term complications.
• Glycogen storage diseases: These rare genetic disorders can cause liver damage and elevations in AST and ALT. A thorough evaluation, including a detailed family history and genetic testing, may be necessary to diagnose these conditions.