Case 14.7 Autoimmune hepatitis
A 43-year-old woman presented with a 5-month history of weight loss (6kg), anorexia, irritability and generalized pruritus. On examination, she was icteric with numerous spider naevi, scratch marks, palmar erythema and hepatosplenomegaly. Investigations showed a low haemoglobin (95g/l) with a normal white-cell count but an erythrocyte sedimentation rate of 140mm/h. The prothrombin time was prolonged but urea and electrolytes, calcium and phosphate concentrations were normal. Although the serum albumin was normal (41g/l), the total serum proteins were raised at 93g/l (NR 62-82) with a raised serum bilirubin of 34µmol/l (NR 1-20), alanine transaminase of 152iu/l (NR 5-30), and aspartate transaminase of 164iu/l (NR 5-45). The alkaline phosphatase level was normal (83iu/l). Her serum immunoglobulins showed an increased IgG level of 44g/l (NR 7.2-19.0) with normal IgA and IgM levels. No paraprotein was present on serum electrophoresis.
Antinuclear antibodies (of IgG class) were strongly positive to a titre of 1/10000 and antibodies to dsDNA were positive (60% binding; normal <30%). Her serum was positive for antibodies to smooth muscle to a titre of over 1/1000 (see Chapter 19). Hepatitis B surface antigen and hepatitis C antibody were absent and AFP was not detected. The immunological picture strongly favoured a diagnosis of autoimmune hepatitis. She was therefore started on prednisolone (30mg/day) and vitamin K, with dramatic improvement. Her serum bilirubin, transaminases and prothrombin time returned to normal over the next fortnight. A diagnostic liver biopsy was performed: this showed chronic active hepatitis with cirrhosis (see below). She was continued on prednisolone (15mg/day) and is fully reassessed every 6 months, including a repeat liver biopsy, as appropriate.