Non hepatotropic virus induced hepatitis - rising importance in a changing world

A knowledge of the epidemiology and clinical aspects of non-hepatotropic viruses is becoming increasingly important in lieu of the rising incidence of acute liver injury caused by them in various circumstances. Broadly, they include the Herpesviridae group, the hemorrhagic fever viruses and certain respiratory viruses that infect the liver. They can affect both the immunocompetent and the immunocompromised individual, more commonly the latter as part of disseminated systemic infection with symptoms ranging from self-limited transaminitis to acute liver failure Various reasons for their rising importance are increased exposure to these viruses by way of: (1) Overcrowding, climatic and environmental changes, increasing tourism and settlement in hitherto unexplored areas where they are endemic and spread either by direct contact or through local fauna which serve as their reservoir host; and (2) Tampering with the normal protective human immunity by using immunomodulator drugs in scenarios of organ transplants, immune and non-immune related inflammatory disorders and various cancers, all of which are rising in incidence due to the aging world population living longer with many comorbidities. As such infections are relatively rare with non-specific presentation, and self-limited clinical course, they are seldom thought of or investigated for in the early disease stages which lead to the development of complications. This review of the most common non-hepatotropic viruses focusses on their epidemiology, etiopathogenesis, clinical manifestations, and management. They should be listed in the differential diagnosis of acute liver injury in appropriate clinical setting like recent travel to endemic areas, immunocompromised state, or exposure to these viruses.