Differential Diagnosis

The patient presents with increasing fatigue and difficulty sleeping, along with laboratory abnormalities, most notably an elevated γ-Glutamyltransferase (GGT) level. The differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis

  • Alcohol (C): The elevated GGT level is a strong indicator of alcohol use, as GGT is a sensitive marker for alcohol-induced liver injury. The patient's symptoms of fatigue and difficulty sleeping could also be related to alcohol consumption. The lack of other significant laboratory abnormalities also points towards alcohol as the most likely cause.

• Other Likely Diagnoses

  • Acetaminophen (A): While acetaminophen can cause liver enzyme elevations, the pattern of elevation (particularly the isolated elevation of GGT without significant elevations in AST or ALT) is less typical for acetaminophen toxicity. However, it remains a consideration, especially if the patient is using acetaminophen regularly.
  • Estrogen effect (D): Estrogen can affect liver function and potentially lead to mild elevations in liver enzymes. Given the patient's gender and the fact that she is likely in a perimenopausal age range, hormonal influences could be contributing to her symptoms and laboratory findings.

• Do Not Miss Diagnoses

  • Ibuprofen (E): Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen can cause liver enzyme elevations and should be considered, especially if the patient is taking these medications regularly. Missing NSAID-induced liver injury could lead to significant morbidity if not addressed.
  • Diphenhydramine (C): Although less common, certain medications like diphenhydramine can cause liver enzyme abnormalities. While it is less likely, it is crucial not to miss drug-induced liver injury, which could be caused by a variety of medications, including antihistamines like diphenhydramine.

• Rare Diagnoses

  • Other liver diseases: Such as autoimmune hepatitis, primary biliary cirrhosis, or other rare liver conditions that could cause an isolated elevation in GGT. These conditions are less likely given the patient's presentation and the absence of other significant laboratory abnormalities but should be considered if other explanations are ruled out.
  • Genetic disorders: Certain genetic disorders can affect liver enzyme levels, but these would be rare and typically present with more significant and earlier onset abnormalities.