In a course of epidemic of hepatitis, fulminant hepatitis is seen in

Fulminant hepatic failure (FHF) is usually defined as the severe impairment of hepatic functions or severe necrosis of hepatocytes in the absence of preexisting liver disease. However, unlike in adults, encephalopathy may be absent, late, or apparent in children only at the terminal stages. Thus, the emphasis in children is placed on the presence of significant coagulopathy in the absence of sepsis or disseminated intravascular coagulation that is not correctable by the administration of parenteral vitamin K within 8 hours. Ref Davidson edition23rd pg883