Serial changes in liver function tests in patients with thyrotoxicosis induced by Graves' disease and painless thyroiditis.
BACKGROUND
When the liver function tests are aggravated after starting antithyroid drugs (ATDs) in Graves' hyperthyroidism, discontinuation of ATDs is generally considered. However, a question arises whether such aggravation constitutes an adverse effect of the drugs or not.


OBJECTIVE
The aim of this study was to clarify the influence of thyrotoxicosis on liver function tests, comparing the results with those in thyrotoxicosis induced by painless thyroiditis.


METHODS
We prospectively studied liver biochemical tests in 30 patients with Graves' disease and in 27 patients with painless thyroiditis.


RESULTS
Twenty-three (76.7%) untreated Graves' disease patients and 14 (51.9%) untreated painless thyroiditis patients were found to have at least one liver function test abnormality. One month after starting ATD therapy in patients with Graves' disease, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) elevations from initial values were observed in 16 (53.3%). Similar elevations of AST and ALT from initial values at 1 month were observed in 10 (37.0%) and 7 (25.9%) patients with painless thyroiditis, respectively. Alkaline phosphatase (ALP) increased gradually after starting ATD therapy and maintained an elevated value for 3-5 months in Graves' disease. In painless thyroiditis, ALP also increased gradually, similarly to that in Graves' disease, but changes were mild. Elevation of ALT after 1 month of ATD therapy in Graves' disease was significantly higher in patients whose estimated disease duration was 6 months or more compared to those with duration of less than 6 months. Elevated AST and ALT at 1 month after ATD therapy decreased to normal ranges, even though patients were receiving the same ATDs in Graves' disease.


CONCLUSIONS
Similar serial changes in liver function tests in both Graves' disease and painless thyroiditis strongly suggest that increases of AST and ALT after starting ATD therapy may not be due to ATD side effects but may be induced by changes in thyroid function.
Kubota
Sumihisa
S
Kuma Hospital, 8-2-35, Shimoyamate-dori, Chuo-ku, Kobe 650-0011, Japan. kubota@kuma-h.or.jp
Amino
Nobuyuki
N
Matsumoto
Yuka
Y
Ikeda
Naoko
N
Morita
Shinji
S
Kudo
Takumi
T
Ohye
Hidemi
H
Nishihara
Eijun
E
Ito
Mitsuru
M
Fukata
Shuji
S
Miyauchi
Akira
A
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D013956:Antithyroid Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001219:Aspartate Aminotransferases / Q000097:blood; D018450:Disease Progression; D016903:Drug Monitoring; D005260:Female; D005500:Follow-Up Studies; D006111:Graves Disease / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D006801:Humans; D008107:Liver Diseases / Q000175:diagnosis / Q000209:etiology*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D010146:Pain; D011446:Prospective Studies; D013966:Thyroiditis / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D013971:Thyrotoxicosis / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D005723:gamma-Glutamyltransferase / Q000097:blood
D013956:Antithyroid Agents; D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase