Endocrine Abstracts

Pituitary resistance to thyroid hormone (PRTH) is a rare, genetic cause of hyperthyroidism. It is characterized by a high concentration of free thyroid hormones, coexisting with elevated or normal concentration of thyroid stimulating hormone. The most prevalent features of this syndrome are typical symptoms of hyperthyroidism and goitre. Diagnosis of this condition does not exclude other comorbidities of the thyroid gland, including these of autoimmune origin. We present the case of a 55-year old woman with symptoms of hyperthyroidism, in the clinical picture seen as tachycardia and thyroid laboratory tests suggesting secondary thyroid disorder. During the diagnostic process focal lesions in the thyroid were ruled out, and TRH stimulation test revealed more than 10-fold rise in TSH concentration. What is interesting, an autoimmune thyroiditis was diagnosed. Thyroid ultrasound showed an unenlarged thyroid gland (total volume 12.3 ml) with a diffusely decreased echogenicity. The patient received thiamazole at first, however due to malaise and poor tolerance the antithyroid treatment was discontinued. Due to the elevated fT3 and fT4 levels and minimal symptoms of hyperthyroidism, the patient was given bromocriptine at a dose of 2.5 mg per day. After 5 months of treatment the patient was euthyroid and has remained in this state to this day.