A case of an acute exacerbation of liver injury in a chronic HBV infected young male is reported. The correlation between the severe symptomatic hepatitis is done with the histopathologic findings of extensive areas of bridging necrosis on the liver biopsy. The serological pattern for markers of HBV (HBsAG +, anti HBs-, HBeAg-, anti HBe+, anti HBc IgG + and IgM-) confirm a chronic infection, and the authors propose that the episode of severe hepatitis relates to the recent spontaneous seroconversion of HBeAg to anti HBe. Other causes of hepatitis were excluded, and the control liver biopsy (6 months later) showed normalization of hepatic architecture and absence of markers of viral replication in tissue and serum. A review of literature is done in an attempt to elucidate the diagnostic possibilities in this case, with emphasis on new immunoassays useful in differentiating between acute hepatitis B and acute exacerbation of a chronic hepatitis by the same virus.