Aetiology and prognosis of fulminant viral hepatitis in Japan: a multicentre study. The Study Group of Fulminant Hepatitis.

In 236 patients with fulminant viral hepatitis (FVH), type B (FBH) was most common (47.5%), followed by non-A non-B hepatitis (FNANB, 44.9%) and hepatitis type A (FAH, 7.6%). The survival rate was significantly higher in the FAH group than in the FBH and FNANB groups (61.1, 36.6 and 18.9% respectively), and was significantly higher in the FBH group than in the FNANB group. In spite of screening for hepatitis B virus (HBV), FBH was prevalent (27 of 41) in post-transfusion cases; this phenomenon is discussed in relation to a recently revealed mutation of HBV. Within a month after the onset of hepatitis symptoms all cases in the FAH, 93% in the FBH and 79% in the FNANB group, developed encephalopathy. When the duration of illness before the onset of encephalopathy was more than 10 days (a subacute form), the survival rate was significantly lower than when encephalopathy developed in less than 11 days (an acute form). This difference could be accounted for by the difference in the relative frequency of aetiological viruses in the two forms and the higher survival rate in the acute, than the subacute, form in the FNANB group.