Thyroid Hormone Replacement in Total Thyroidectomized Patients: Symptomatic and Metabolic Effects of Levothyroxine Monotherapy

Abstract

In this study, we planned to investigate the effects of L-thyroxine monotherapy on total thyroidectomized patients. The main goal of our study is to evaluate if FT4 therapy is good enough not only to maintain euthyroidism but also to provide a good quality of life and a balance in their metabolism Methods: In this study, we retrospectively evaluated 30 total thyroidectomized patients without malignancy. We compared their thyroid hormone levels, glucose metabolism, lipid metabolism, their body mass indexes, and their symptoms of thyroid problems before surgery and after one year of treatment of L-thyroxine monotherapy.Results: the pre-op and post-op thyroid hormone levels were both in the normal range but the FT4 levels were significantly higher in the 1st year results than pre-op results (1,42 ± 0,18 vs 1,29 ± 0,49 respectively P=0,005*) The FT3 levels also were in the normal range in pre and 1st year post-op but post-op FT3 levels were significantly lower than pre-op levels (2,25 ± 0,27 vs 2,92 ± 0,49 retrospectively P<0,001*). The pre-op and postop TSH levels were euthyroid and not statistically significant. The patients tended to gain weight and it seems to be because of a tendency of being insulin resistant. (HOMA-IR pre-op and post-op were 2,2 ± 1,1 vs 2,6 ± 1,1 P<0,01 retrospectively; pre-op and post-op weights were 69,8 ± 9,5 vs 71,1 ± 10,3 P=0,006* respectively). Even all of them were euthyroid the patients tended to feel hypothyroidism symptoms. Conclusion:This study demonstrates that even though they are euthyroid with FT4 treatment total thyroidectomized patients may suffer from hypothyroidism signs and symptoms and metabolic deterioration may occur in such patients. We recommend that we should aim not only to normalize s-TSH levels but also to normalize patients' metabolic parameters and improve the quality of daily life when regulating our treatments.