Endocrine Abstracts

Abstract learning objective: Resistance to thyroid hormone is a rare condition caused by tissue refractiveness to the effects of circulating thyroid and may be misdiagnosed as hyperthyroidism. This syndrome is characterized by elevated circulating thyroid hormones, and unsuppressed TSH levels. Although most patients are euthyroid, rarely they may present with clinical hyperthyroidism, if the Pituitary gland is more insensitive than other tissues to thyroid hormones.

In this study we present a case of Graves disease on a background of thyroid resistance.

Case: 54 year old lady who suffered from loss of weight and diarrhoea for two years, with a family history of two of her sisters having been diagnosed with thyroid resistance, had clinical evidence of thyrotoxicosis. TFT’s showed TSH<0.03, FT₃>30.8, TRAB 0.8, Sonography revealed diffuse alteration of echogenicity and increased vascularity suggestive of Graves disease and a small nodule 8mm nodule in right lobe. Patient was treated with Propranolol 40 mg BD and carbimazole 30 mg and subsequently reduced to 20 mg a day. After 6 months of treatment TSH (2.34) normalised with FT₃ 10.1 and FT₄ 29. At this stage a NM scan was performed to see if the thyroid nodule was toxic, it showed a small diffuse goitre, diffuse symmetrical uptake throughout, alpha subunit was normal (1.15). In this case report we emphasized the importance of timely diagnosis, and therefore various inappropriate treatments were avoided.