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

Abstract

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.

Keywords: Viral hepatitis; Non-hepatotropic virus; Acute liver injury; Acute liver failure; Hemorrhagic fever virus

Core Tip: Liver infection by non-hepatotropic viruses is increasingly being encountered in the setting of emerging and re-emerging viral diseases the world over and the increasing use of immune altering medications in situations like organ transplant, immune mediated diseases and cancers, especially in the aging world population living with many comorbidities. Symptomatology can range from self-limited transaminitis in the immunocompetent to disseminated disease with acute liver failure in the immunocompromised. They are seldom detected as most infections have non-specific presentation and are self-limited. Early diagnosis can prevent complications. This review summarizes their epidemiology, clinical manifestations and management.