Thyroid Function Tests in Patients with Acute and Resolved Hepatitis B Virus Infection

Abstract

Serum thyroid hormones and thyroid hormone binding were sequentially measured in 20 patients with acute hepatitis B infection. Criteria to select patients consisted of a positive test for hepatitis B surface antigen, aspartate aminotransferase (AsAT) concentration greater than 400 U/L during the acute illness, and available serum specimens after recovery. The mean serum thyroxine (T4) concentration (±SE) was 12.5 ± 0.6 µ/dL during acute infection and 7.4 ± 0.3 µ/dL after recovery (p < 0.001), whereas mean free T4 index values did not significantly differ. The mean serum thyroxine-binding globulin (TBG) concentration was significantly increased (p < 0.001) during acute illness and accounted for the reversible increase in the thyroid-hormone-binding capacity of serum and the increased serum T4 concentrations. The rise in serum TBG correlated with the rise in AsAT during the acute illness (p < 0.04) suggesting nonspecific release of these proteins from injured hepatocytes. The mean free triiodothyronine (T3) index was decreased during acute hepatitis (p < 0.001) and returned to normal after recovery, indicating that acute hepatitis B infection, like other nonthyroidal illnesses, is associated with decreased T4 to T3 conversion in peripheral tissues.