Endocrine Abstracts

Introduction: Graves’ disease and Hashimoto’s hypothyroidism are common thyroid diseases. However, occurrence of both clinical disorders one after the other in the same patient, is not common.

Case report: In this article, we presented two hypothyroid patients who developed clinical thyrotoxicosis during levothyroxine treatment. Both patients were treated with levothyroxine for a long time. Due to occurrence of clinical hyperthyroidism, levothyroxine treatments of the both patients were terminated. Although unmedicated follow-up for about 6 weeks period, recovery from thyrotoxicosis wasn’t observed. Both of the patients were positive for TSH receptor antibody.

Results: They were diagnosed as Graves’ disease on the basis of clinical signs, laboratory findings and imaging techniques, thus antithyroid treatment was initiated. In both cases, TSH receptor gene sequence analysis was performed, and in both of the patients D727E homozygous polymorphism was obtained.

Conclusions: In hyperthyroid cases with the history of hypothyroidism, switching between hypothyroidism and hyperthyroidism should be kept in mind and due to D727E polymorphism, and the other TSH receptor gene mutations, if it is possible genetic analysis should be performed.