Subacute hepatic failure: diagnosis of exclusion?

Subacute hepatic failure has been a controversial diagnosis ever since it was first identified more than 15 years ago. The Working Committee on Subacute Hepatic Failure has attempted to redefine this entity in which exclusion of preexisting cirrhosis on liver biopsy has been emphasized. Acute viral hepatitis in a patient with asymptomatic chronic liver disease (e.g., hepatitis B or C, Wilson's disease) can be misdiagnosed as subacute hepatic failure in the absence of a liver biopsy. This situation is common in developing countries where the prevalence of feco-orally transmitted (hepatitis A [<20 years] and hepatitis E [>20 years]) and parenterally transmitted (hepatitis B) viruses is high. To obtain and interpret liver biopsy specimens in such a situation is difficult and hazardous, and hence rarely performed. Acute viral hepatitis in a patient with asymptomatic chronic liver disease should be carefully looked for and excluded, especially in developing countries, before a diagnosis of subacute hepatic failure is confirmed.