Differential Diagnosis

The patient's presentation is complex, with intractable vomiting, mild transaminitis, azotemia, and conjunctival injection. The following differential diagnoses are considered:

• Single Most Likely Diagnosis
  • Viral Hepatitis: The patient's liver function tests (LFTs) show a pattern of mild transaminitis, which could be indicative of viral hepatitis. The initial improvement in LFTs followed by a rise could suggest a fluctuating course, which is sometimes seen in viral hepatitis. The presence of conjunctival injection could be related to the systemic effects of the hepatitis virus.
• Other Likely Diagnoses
  • Autoimmune Hepatitis: This condition can present with transaminitis and may have a fluctuating course. The absence of a clear infectious cause and the presence of systemic symptoms such as nausea and conjunctival injection could support this diagnosis.
  • Drug-Induced Liver Injury (DILI): Although the patient has been treated with several medications, the temporal relationship between medication use and the rise in LFTs is not clear. However, DILI remains a possibility, especially if the patient has been exposed to other medications or substances not mentioned.
  • Wilson's Disease: This genetic disorder can cause liver dysfunction and may present with a variety of symptoms, including nausea and conjunctival findings (Kayser-Fleischer rings, though not mentioned). However, the age of presentation and the lack of specific neurological symptoms make this less likely.
• Do Not Miss Diagnoses
  • Budd-Chiari Syndrome: Although the 2D echo is normal, this condition can cause liver dysfunction due to hepatic vein thrombosis. It's crucial to consider this diagnosis due to its potential for severe consequences if missed.
  • Acute Intermittent Porphyria: This rare genetic disorder can cause severe abdominal pain, nausea, and neurological symptoms. Although less likely, it's a critical diagnosis not to miss due to its potential for severe complications.
• Rare Diagnoses
  • Weil's Disease (Leptospirosis): Despite the negative leptospira antigen and lack of endemic area, leptospirosis can have a wide range of presentations. If the patient has had any exposure to contaminated water, this diagnosis should still be considered.
  • Rickettsial Diseases: Although the area is not endemic, travel history or exposure to ticks could still place this in the differential, albeit rarely.
  • Hemochromatosis: A genetic disorder leading to iron overload, which can cause liver dysfunction among other symptoms. This would be less likely given the patient's age and sex but remains a consideration in the broad differential for liver disease.

Next Steps

Given the differential diagnoses, the next steps could include:

• Further liver function tests and viral hepatitis serologies to evaluate for viral hepatitis.
• Autoimmune hepatitis panel to assess for autoimmune causes.
• Detailed medication and substance use history to evaluate for DILI.
• Consider imaging studies (e.g., ultrasound, MRI) to evaluate liver morphology and rule out structural causes like Budd-Chiari syndrome.
• If Wilson's disease is considered, 24-hour urinary copper and serum ceruloplasmin levels could be helpful.
• For porphyrias, a spot urine test for porphobilinogen (PBG) could be diagnostic during an acute attack.