Serial Changes in Liver Function Tests in Patients with Thyrotoxicosis Induced by Graves' Disease and Painless Thyroiditis

摘要

Context: When the liver function tests are aggravated after starting antithyroid drugs (ATDs) in Graves’ hyperthyroidism,ndiscontinuation of ATDs is generally considered. However, a question arises whether such aggravationnconstitutes an adverse effect of the drugs or not.nObjective: The aim of this study was to clarify the influence of thyrotoxicosis on liver function tests, comparingnthe results with those in thyrotoxicosis induced by painless thyroiditis.nDesign: We prospectively studied liver biochemical tests in 30 patients with Graves’ disease and in 27 patientsnwith painless thyroiditis.nMain outcomes: Twenty-three (76.7%) untreated Graves’ disease patients and 14 (51.9%) untreated painlessnthyroiditis patients were found to have at least one liver function test abnormality. One month after startingnATD therapy in patients with Graves’ disease, aspartate aminotransferase (AST) and alanine aminotransferasen(ALT) elevations from initial values were observed in 16 (53.3%). Similar elevations of AST and ALT from initialnvalues at 1month were observed in 10 (37.0%) and 7 (25.9%) patients with painless thyroiditis, respectively.nAlkaline phosphatase (ALP) increased gradually after starting ATD therapy and maintained an elevated valuenfor 3–5 months in Graves’ disease. In painless thyroiditis, ALP also increased gradually, similarly to that innGraves’ disease, but changes were mild. Elevation of ALT after 1month of ATD therapy in Graves’ disease wasnsignificantly higher in patients whose estimated disease duration was 6 months or more compared to those withnduration of less than 6months. Elevated AST and ALT at 1 month after ATD therapy decreased to normalnranges, even though patients were receiving the same ATDs in Graves’ disease.nConclusion: Similar serial changes in liver function tests in both Graves’ disease and painless thyroiditis stronglynsuggest that increases of AST and ALT after starting ATD therapy may not be due to ATD side effects but maynbe induced by changes in thyroid function.nIntroduction