Endocrine Abstracts

Introduction: The most common cause of hyperthyroidism in Malaysia is autoimmune cause like Grave disease, or toxic multinodular goitre. Thyroid hormone resistant syndrome is a rare genetic disease which usually presented with mild hyperthyroidism clinically and biochemically it had elevated free T4 and non suppressed TSH. Inexperienced doctor will commonly mistreat patient with antithyroid medication. This is because this genetic disease is extremely rare to encountered in practice.

Case Report: A 24 years old gentleman, he was first presented to Hospital Ipoh for left Anterior Cruciate Ligament tear after sport injury in 2019. Pre-operative assessment noted patient tachycardia. Otherwise, he did not have palpitation, tremors, weight loss, heat or cold intolerance, diarrhea, or anxiety. On the other hand, he had strong family history of hyperthyroidism which were his mother, mother’s siblings and his grandmother. On examination, his blood pressure is normotensive, and heart rate was slightly tachycardic. He had no fine tremors, and goiter. Cardiovascular and respiratory system examination was unremarkable His thyroid biochemical profile showed normal thyroid stimulating hormone (TSH), 3.4 mIU/l (0.55 -4.78) with elevated free T4 (FT4), 27.9 pmol/l (11.5-22.7). In view of pendemic covid, his operation was postponed and he request his case transfer to my hospital, Hospital Melaka to continue follow up. Throughout the follow up, serial thyroid function test showed normal TSH, and elevated FT4. He was asymptomatic for hyperthyroidism other than occasionally tachycardic. His magnetic resonance imaging brain demonstrate a pituitary microadenoma. However, thyrotropin releasing hormone (TRH) stimulation test reveal normal TSH response. We presumed that he had thyroid hormone resistance syndrome, with the given history of mild hyperthyroidism features and the investigation mentioned as above. He is otherwise well without any antithyroid treatment. He had undergone left knee Anterior cruciate ligament tear repair in Jan 2022 under general anesthesia. Intraoperative and postoperative were uneventful. We had our limitation to further workup because the genetic test was not available in our country. We had rule out thyrotropin secreting tumor and primary hyperthyroidism before we come to a conclusion of thyroid hormone resistance syndrome. However, we would like to emphasis that not all hyperthyroidism warrant antithyroid treatment. Early recognition and refer to correct team is crucial to avoid unnecessary treatment.