Clinical and prognostic differences in fulminant hepatitis type A, B and non-A non-B.

In 73 patients with fulminant viral hepatitis, non-A non-B hepatitis (NANB) was most common (43.8%), with hepatitis type A (HAV) diagnosed in 31.5% and hepatitis type B (HBV) in 24.7%. The non-A non-B group had a significantly longer duration from the onset of symptoms to the appearance of encephalopathy (median 21 days) compared with the HAV and HBV groups (medians 10 and seven days, p less than 0.01 and p less than 0.005 respectively). In the HAV group the severity of liver damage, judged by the maximum prolongation of the prothrombin time, was significantly less than in the HBV group (58 and 150 seconds prolonged respectively, p less than 0.005), and cerebral oedema was significantly less frequent (39% and 72% respectively, p less than 0.05). Consistent with this, the survival rate was higher in the HAV group (43.4%) compared with the HBV group (16.6%) and NANB group (9.3%) (p less than 0.005). These variations in presentation and clinical course may be a consequence of differences in the pathogenesis of the hepatic necrosis.