Graves' hyperthyroidism following primary hypothyroidism: sequential changes in various activities of thyrotropin receptor antibodies

Abstract

A 40-year-old male who developed Graves' hyperthyroidism following primary hypothyroidism is reported. He presented with clinical signs of hypothyroidism and concomitant myasthenia gravis. The thyroid was not palpable. He was treated with T4, pyridostigmine and prednisolone. One year later he developed hyperthyroidism and goitre. His initial serum IgG had no intrinsic thyroid stimulating activity, but showed almost complete inhibition of TSH-stimulated cAMP generation (99.4%, normal <38%) and [3H]thymidine incorporation (99.5%, normal<40%) into rat thyroid cells, FRTL-5 cells, with very high activity (80.2%, normal <15%) of TSH binding inhibitor immunoglobulin. When he developed hyperthyroidism and goitre, his IgG showed a strong thyroid stimulation, both cAMP production (27-fold increase) and [3H]thymidine incorporation (5.5-fold increase). No inhibitory activities were noted. These findings suggest that clinical states of autoimmune thyroid diseases can be changed in accordance with changes of functional properties of TSH receptor antibodies.

Occurrence and Spontaneous Remission of Graves' Hyperthyroidism Preceded by Painless Thyroiditis.

“…Noh et al [ Changes in the balance of TSAb and TSBAb activities are known to influence the thyroid state directly [13][14][15], but in this case, TSBAb activity remained undetected throughout the whole clinical course.…”

Thyrotropin-Blocking Autoantibodies and Thyroid-Stimulating Autoantibodies: Potential Mechanisms Involved in the Pendulum Swinging from Hypothyroidism to Hyperthyroidism or Vice Versa

“…TSAb and hyperthyroidism develop unexpectedly in some patients with hypothyroidism that is caused by TBAb (Table 1) (29)(30)(31)(32)(33). This shift in thyroid function occurs only rarely in a disease that is, in itself, rare.…”

“…The relatively sparse available information for this unusual group of patients is related to age, sex, and ethnicity (5,(29)(30)(31)(32)(33)(36)(37)(38)(47)(48)(49)(50)74). The majority of patients with TBAb/TSAb switches (or the reverse) are women, and they have the same age range as other patients with thyroid autoimmune disease (Table 4).…”

Clinical Applications of TSH Receptor Antibodies in Thyroid Diseases

“…TSBAbs may result from a conversion of the bioactivity of TSAb or may coexist with TSAb at the time of hypothyroidism. In addition, several patients with fluctuating thyroid function from hypothyroidism to hyperthyroidism by changing the activity of TSBAb to TSAb have been reported (50). Thus, the measurement of bioactivities of TSHRAbs during the course of Graves' disease is valuable in the case, especially, of fluctuating thyroid function.…”