Acute liver failure: established and putative hepatitis viruses and therapeutic implications

Any virus that can cause an acute hepatitis will, on occasion, give rise to acute liver failure. Such infections can be separated into those due to the primary hepatitis viral infections A to E and those where hepatitis occurs as part of a systemic viral infection, as with infection with, for instance, Epstein-Barr virus, cytomegalovirus, Varicella zoster virus, adenovirus and Herpes simplex virus. In general, the frequency with which the different hepatitis viruses are responsible for acute liver failure is related to their underlying prevalence in particular countries. An apparent exception is the striking geographical variation in the reported prevalence of acute liver failure due to hepatitis C virus infection, with a much higher proportion of cases generally attributed to this agent in Japan and Taiwan than in Western countries. Recent work has focused on the possible importance of mutant hepatitis B viral strains, co- and super-infection with known hepatitis viruses and certain newly described agents that may account for otherwise unexplained cases of acute liver failure. Despite an improved understanding of the pathogenesis of complicating cerebral oedema and advances in general supportive care, it is likely that the most severely affected patients with acute liver failure due to viral causes will survive only with liver transplantation, at least until approaches for promoting adequate liver regeneration are successfully developed and implemented.