Acute liver failure

Diagnostics

• Clinical Diagnostic Triad:
  • 1. Severe acute liver injury (AST & ALT typically > 1000 U/L).
  • 2. Signs of hepatic encephalopathy.
  • 3. INR ≥ 1.5 (synthetic dysfunction).
  • Constraint: Must occur in a patient without pre-existing cirrhosis or chronic liver disease, with a disease duration < 26 weeks.
• Initial/Screening Labs:
  • PT/INR (most important prognostic marker).
  • LFTs (AST, ALT, Bilirubin, ALP).
  • Serum acetaminophen level (mandatory in all cases of ALF).
  • Toxicology screen.
  • Viral serologies (HAV IgM, HBsAg, HBcAb IgM, HCV Ab, HEV IgM).
  • Autoimmune markers (ANA, ASMA, IgG).
  • Ceruloplasmin and copper levels (if Wilson disease suspected).
  • Pregnancy test (rule out HELLP syndrome or acute fatty liver of pregnancy).
• Imaging:
  • RUQ Ultrasound with Doppler: Initial modality of choice to rule out biliary obstruction and assess hepatic/portal vein patency (exclude Budd-Chiari).
• Confirmatory/Gold Standard:
  • Diagnosis is primarily clinical based on the triad. Liver biopsy is rarely required and should only be performed via the transjugular route due to severe coagulopathy.