Case Report: Severe Hypothyroxinemia in a Young Adult with Carbimazole-Treated T3-Predominant Graves’ Hyperthyroidism, Reversed with L-Thyroxine Loading Immediately Post-Total Thyroidectomy

Keywords: Graves' disease, hypothyroxinemia, T3-thyrotoxicosis, L-thyroxin

Abstract

Patients with triiodothyronine (T3)-predominant Graves’ hyperthyroidism with markedly elevated serum thyroid stimulating immunoglobulin (TSI) levels and massive goitre may display discordant hypothyroxinemia with eutriiodothyroninemia or hypertriiodothyroninemia while on anti-thyroid drug therapy. A 25-year-old female with the above was started on oral carbimazole therapy for 9 months before total thyroidectomy. Preoperatively, her serum free T4 was reduced to below detection limit, and total T4 reduced to 11% of lower limit of normal, while T3 levels remained normal, and TSH remained largely suppressed. Immediately after total-thyroidectomy, a loading dose of L-thyroxine (L-T4) was administered intravenously. She was extubated without any postoperative complications. Serum free and total T4, and TSH normalized within the next 24 hours. The peculiar thyroid axis dynamics and use of L-T4 postoperative loading in such a rare clinical scenario are discussed.

Downloads

Download data is not yet available.

Author Biographies

Brenda Chiang, Sengkang General Hospital

Associate Consultant, Department of General Medicine

Yin Chian Kon, Tan Tock Seng Hospital

Department of Endocrinology

References

Takamatsu J, Sugawara M, Kuma K, et al. Ratio of serum triiodothyronine to thyroxine and the prognosis of triiodothyronine-predominant Graves’ disease. Ann Intern Med 1984;100(3):372-5. https://pubmed.ncbi.nlm.nih.gov/6546484. https://doi.org/10.7326/0003-4819-100-3-372.

Chen JJ, Ladenson PW. Discordant hypothyroxinemia and hypertriiodothyroninemia in treated patients with hyperthyroid Graves’ disease. J Clin Endocrinol Metab. 1986;63(1):102–6. https://pubmed.ncbi.nlm.nih.gov/2423547. https://doi.org/10.1210/jcem-63-1-102.

Takamatsu J, Hosoya T, Naito N, et al. Enhanced thyroid iodine metabolism in patients with triiodothyronine-predominant Graves’ disease. J Clin Endocrinol Metab. 1988;66(1):147–52. https://pubmed.ncbi.nlm.nih.gov/3335601. https://doi.org/10.1210/jcem-66-1-147.

Larsen PR. Thyroidal triiodothyronine and thyroxine in Graves' disease: Correlation with presurgical treatment, thyroid status, and iodine content. J Clin Endocrinol Metab. 1975;41(06):1098-104. https://pubmed.ncbi.nlm.nih.gov/54364. https://doi.org/10.1210/jcem-41-6-1098.

Laurberg P, Vestergaard H, Nielsen S, et al. Sources of circulating 3,5,3’-triiodothyronine in hyperthyroidism estimated after blocking of type 1 and type 2 iodothyronine deiodinases. J Clin Endocrinol Metab. 2007;92(6):2149–56. https://pubmed.ncbi.nlm.nih.gov/17389703. https://doi.org/10.1210/jc.2007-0178.

Dalan R, Kon W, Phenotypic expression and challenges of a distinct form of thyrotoxicosis: Triiodothyronine-predominant Graves’ disease – aggressive, refractory, and anything but banal. Endocrinologist. 2008;18(2):90-4. ScholarBank@NUS Repository. https://doi.org/10.1097/TEN.0b013e3181693d5e.

Gereben B, McAninch EA, Ribeiro MO, Bianco AC. Scope and limitations of iodothyronine deiodinases in hypothyroidism. Nat Rev Endocrinol. 2015;11(11):642-52. https://pubmed.ncbi.nlm.nih.gov/26416219. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5003781. https://doi.org/10.1038/nrendo.2015.155.

Gereben B, Zavacki AM, Ribich S, et al. Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocr Rev. 2008;29(7):898-938. https://pubmed.ncbi.nlm.nih.gov/18815314. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2647704. https://doi.org/10.1210/er.2008-0019.

Christoffolete MA, Ribeiro R, Singru P, et al. Atypical expression of type 2 iodothyronine deiodinase in thyrotrophs explains the thyroxine-mediated pituitary thyrotropin feedback mechanism. Endocrinology. 2006;147(4):1735-43. https://pubmed.ncbi.nlm.nih.gov/16396983. https://doi.org/10.1210/en.2005-1300.

Prummel MF, Brokken LJS, Wiersinga WM. Ultra-short-loop feedback of thyrotropin secretion. Thyroid. 2004;14(10):825-9. https://pubmed.ncbi.nlm.nih.gov/15588378. https://doi.org/10.1089/thy.2004.14.825.

Brokken LJS, Scheenhart JWC, Wiersinga WM, Prummel MF. Suppression of serum TSH by Graves’ Ig: Evidence for a functional pituitary TSH receptor. J Clin Endocrinol Metab. 2001;86(10):4814-7. https://pubmed.ncbi.nlm.nih.gov/11600546. https://doi.org/10.1210/jcem.86.10.7922.

Prummel MF, Brokken LJ, Meduri G, Misrahi M, Bakker O, Wiersinga WM. Expression of the thyroid-stimulating hormone receptor in the folliculo-stellate cells of the human anterior pituitary. J Clin Endocrinol Metab. 2000; 85(11):4347-53. https://pubmed.ncbi.nlm.nih.gov/11095478. https://doi.org/10.1210/jcem.85.11.6991.

Chung YJ, Lee BW, Kim JY, et al. Continued suppression of serum TSH level may be attributed to TSH receptor antibody activity as well as the severity of thyrotoxicosis and the time to recovery of thyroid hormone in treated euthyroid Graves’ patients. Thyroid. 2006;16(12):1251-7. https://pubmed.ncbi.nlm.nih.gov/17199435. https://doi.org/10.1089/thy.2006.16.1251.

Pedraza PE, Obregon MJ, Escobar-Morreale HF, Escobar del Rey F, Morreale de Escobar G. Mechanisms of adaptation to iodine deficiency in rats: Thyroid status is tissue specific. Its relevance for man. Endocrinology. 2006; 147(5):2098-108. https://pubmed.ncbi.nlm.nih.gov/16455775. https://doi.org/10.1210/en.2005-1325.

Fonseca TL, Correa-Media M, Campos MPO, et al. Coordination of hypothalamic and pituitary T3 production regulates TSH expression. J Clin Invest 2013;123(4):1492-500. https://pubmed.ncbi.nlm.nih.gov/23524969. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3613903. https://doi.org/10.1172/JCI61231.

Alexander EK, Pearce EN, Brent GA, et al. 2017 Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and the postpartum. Thyroid 2017;27(3):315-89. https://pubmed.ncbi.nlm.nih.gov/28056690. https://doi.org/10.1089/thy.2016.0457.

Holvey DN, Goodner CJ, Nicoloff JT, Dowling JT. Treatment of myxoedema coma with intravenous thyroxine. Arch Int Med. 1964;113:89-96. https://pubmed.ncbi.nlm.nih.gov/14067598. https://doi.org/10.1001/archinte.1964.00280070091015.

Arlot S, Debussche X, Lalau JD, et al. Myxoedema coma: Response of thyroid hormones with oral and intravenous high-dose L-thyroxine treatment. Intensive Care Med. 1991;17(1):16-8.https://pubmed.ncbi.nlm.nih.gov/2037720. https://doi.org/10.1007/BF01708403.

Ridgway EC, McCammon JA, Benotti J, Maloof F. Acute metabolic responses in myxoedema to large doses if intravenous L-thyroxine. Ann Int Med. 1972:77(4):549-55. https://pubmed.ncbi.nlm.nih.gov/4642735. https://doi.org/10.7326/0003-4819-77-4-549.

Published
2021-04-18
How to Cite
Chiang, B., & Kon, Y. C. (2021). Case Report: Severe Hypothyroxinemia in a Young Adult with Carbimazole-Treated T3-Predominant Graves’ Hyperthyroidism, Reversed with L-Thyroxine Loading Immediately Post-Total Thyroidectomy. Journal of the ASEAN Federation of Endocrine Societies, 36(1). Retrieved from https://asean-endocrinejournal.org/index.php/JAFES/article/view/997
Section
Case Reports