Abstract
In order to elucidate causes of subclinical thyrotoxicosis, we reviewed records of thyroid function tests obtained in our hospital between 1990 and 1992, showing normal thyroid hormones and subnormal TSH levels, and analyzed underlying clinical conditions of the patients. Of 186 patients with normal T4 and/or free T4 and normal T3 and/or free T3 but subnormal TSH (<0.1 mU/l) levels in serum, 150 were under treatment with antithyroid drugs for hyperthyroid Graves’ disease or with thyroid hormones for hypothyroidism. Twelve were in remission after treatment for Graves’ disease, and 4 had destructive thyroiditis. Of the remaining 20 patients, 4 had autonomously functioning thyroid nodule (AFTN), 9 had euthyroid ophthalmic Graves’ disease (EOG), and 7 had diffuse goiter without apparent ophthalmopathy (DG). When thyroid stimulating antibodies (TSAb) were measured in the last 3 groups of the patients, they were detected in none with AFTN but in all patients with EOG and DG. These 7 DG patients without ophthalmopathy had a clinical feature showing unstable thyroid functions, changeable to euthyroidism, overt hyperthyroidism and even hypothyroidism during follow-up. In conclusion, TSAb measurement is useful for detection of subclinical Graves’ disease in euthyroid subjects with subnormal TSH levels in serum.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Ross D.S., Ardisson L.J., Meskell M.J. Measurement of thyrotropin in clinical and subclinical hyperthyroidism using a new chemiluminescent assay. J. Clin. Endocrinol. Metab. 69: 684, 1989.
Ehrmann D.A., Weinberg M., Same D.H. Limitation to the use of a sensitive assay for serum thyrotropin in the assessment of thyroid status. Arch. Intern. Med. 149: 369, 1989.
Spencer C.A., Nicoloff J.T. Serum TSH measurement: a 1990 status report. Thyroid Today 8: 1, 1990.
Utiger R.D. Subclinical hyperthyroidism — just a low seum thyrotropin concentration, or something more? (Editorial). N. Engl. J. Med. 331: 1302, 1994.
Ross D.S. Subclinical thyrotoxicosis. In: Braverman L.E., Utiger R.D. (Eds.), Werner and Ingbar’s The Thyroid, ed. 7. Lippincott Raven, Philadelphia, 1996, p. 1016.
Werner S.C. Classification of the eye change in Graves’ disease. J. Clin. Endocrinol. Metab. 29: 982, 1969.
Southgate K., Creagh F., Teece M., Kingswood C., Smith B.R. A radioreceptor assay for the measurement of TSH receptor antibodies in unextracted serum. Clin. Endocrinol. (Oxf.) 20: 539, 1984.
Konishi J., Kasagi K., Lida Y., Kousaka T., Misaki T., Arai K., Tokuda Y., Torizuka K. Optimization and clinical assessment of a radioreceptor assay for thyrotropin binding inhibitor immunoglobulins. Endocrinol. Jpn. 34: 13, 1987.
Kasagi K., Konishi J., Lida Y., Tokuda Y., Arai K., Endo K., Torizuka K. A sensitive and practical assay for thyroid stimulating antibodies using FRTL-5 thyroid cells. Acta Endocrinol. (Copenh.) 115: 30, 1987.
Kasagi K., Hatabu H., Tokuda Y., Lida Y., Endo K., Konishi J. Studies on thyrotropin receptor antibodies in patients with euthyroid Graves’ disease. Clin. Endocrinol. (Oxf.) 29: 357, 1988.
Bayer M.F., Kriss J.P., McDougall I.R. Clinical experience with sensitive thyrotropin measurements: diagnostic and therapeutic implications. J. Nucl. Med. 26: 1248, 1985.
Wilson R., Semple C.G., Reld A.M., Glen A.C.A., McKillop J.H., Thomson J.A. Can thyroid stimulating hormone levels by TSH (IRMA) predict relapse of thyrotoxicosis following Carbimazole treatment? Postgrad. J. Med. 63: 755, 1987.
Ross D.S., Daniels G.H., Gouveia D. The use and limitation of a chemiluminescent thyrotropin assay as a single thyroid function test in an out-patient endocrine clinic. J. Clin. Endocrinol. Metab. 71: 764, 1990.
Parma J., Duprez L., Sande J.V., Cochaux P., Gervy C., Mockel J., Dumont J., Vassart G. Somatic mutations in the thyrotropin receptor gene cause hyperfunctioning thyroid adenoma. Nature 365: 649, 1993.
Kreiem Z., Glaser B., Yigla M., Pauker J., Sadeh D., Sheinfeld M. Toxic multinodular goiter: a variant of autoimmune hyperthyroidism. J. Clin. Endocrinol. Metab. 65: 659, 1987.
Franco P.S., Hershman J.M., Haigier E.D., Pittman J.A. Response to thyrotropin-releasing hormones compared with thyrotropin suppression tests in euthyroid Graves’ disease. Metabolism 22: 1357, 1973.
Tamai H., Nakagawa T., Ohsako N., Fukino O., Takahashi H., Matsuzuka F., Kuma K., Nagataki S. Changes in thyroid functions in patients with euthyroid Graves’ disease. J. Clin. Endocrinol. Metab. 50: 108, 1980.
Kasagi K., Hatabu H., Misaki T., Miyamoto S., Takeuchi R., Sakahara H., Sasayama S., Lida Y., Konishi J. Scintigraphic findings of the thyroid in euthyroid ophthalmic Graves’ disease. J. Nucl. Med. 35: 811, 1994.
Bregengaard C., Kirkegaard C., Faber J., Poulsen S., Hasselstorom K., Siersbaek-Nielsen K., Friis T. Relationship between serum thyrotropin, serum free thyroxine (T4), and 3, 5, 3′-triiodothyronine (T3) and the daily T4 and T3 production rates in euthyroid patients with multinodular goiter. J. Clin. Endocrinol. Metab. 65: 258, 1987.
Rieu M., Bekka S., Sambor B., Berrod J-L., Fombeur J-P. Prevalence of subclinical hyperthyroidism and relationship between thyroid hormonal status and thyroid ultrasonographic parameters in patients with non-toxic nodular goiter. Clin. Endocirnol. (Oxf.) 139: 67, 1993.
Scott D.J., McLellan A.R., Finlayson J., Chu P., Alexander W.D. Elderly patients with suppressed serum TSH but normal free thyroid hormone levels usually have mild thyroid overactivity and are at increased risk of developing overt hyperthyroidism. Quart. J. Med. 285: 77, 1991.
Smyth P.P.A., Neylan D., O’Donovan D.K. Association of thyroid-stimulating immunoglobulins and thyrotropin-releasing hormone responsiveness in women with euthyroid goiter. J. Clin. Endocrinol. Metab. 57: 1001, 1983.
Brown R.S., Jackson I.M.D., Pohl S.L., Reichlin S. Do thyroid stimulating immunoglobulins cause nontoxic and toxic multinodular goiter? Lancet 1: 904, 1978.
Studer H., Gebel F. Toxic nodular goiter. Clin. Endocrinol. Metab. 14: 351, 1985.
Lauberg P., Pedersen K.M., Vestergaard H., Sigurdsson G. High incidence of multinodular toxic goiter in the elderly population in a low iodine intake area vs. incidence of Graves’ disease in the young in a high iodine intake area: comparative surveys of thyrotoxicosis epidemiology in East-Jutland Denmark and Iceland. J. Intern. Med. 2298: 415, 1991.
Tamai H., Kasagi K., Morita T., Hidaka A., Kuma K., Konishi J., Kumagai L.F., Nagataki S. Thyroid response, especially to thyrotropin-binding inhibitor immunoglobulins in euthyroid relatives of patients with Graves’ disease: a clinical follow-up. J. Clin. Endocrinol. Metab. 71: 210, 1990.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kasagi, K., Takeuchi, R., Misaki, T. et al. Subclinical Graves’ disease as a cause of subnormal TSH levels in euthyroid subjects. J Endocrinol Invest 20, 183–188 (1997). https://doi.org/10.1007/BF03346900
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF03346900