Endocrine Abstracts

A 60–year-old male and 24–year-old female presented to the endocrinologist with hyperthyroidism of unknown cause. A 60-year-old male was admitted to the Department of Endocrinology with fatigue, dyspnoea, increased sweating, and anxiety. Hyperthyroidism was diagnosed with TSH < 0.0008 mIU/l [reference range: 0.3500 – 4.9400], FT4 – 4.03 ng/dl [reference range: 0.89 – 1.76] and FT3 – 12.96 [reference range: 2.3-4.2]. The patient had a history of congenital heart disease, myocardial infarction, dilated cardiomyopathy, Cardiac Resynchronisation Therapy with Defibrillator device implantation, aortic valve replacement, and because of progression of chronic heart failure (NYHA class IV) the HeartMate 3 Left Ventricular Assist Device (LVAD) implantation two years ago. A 24-year-old female visited the endocrinologist in an Outpatient clinic. She complained about nausea and vomiting almost every day, fatigue, and hand tremor. The blood test showed hyperthyroidism: TSH < 0.008 mIU/l, FT4 – 4.4 ng/dl and FT3 – 12.49 pg/ml . Since the age of 3, the patient has been diagnosed with Wolff–Parkinson–White syndrome and left ventricular hypertrophy, later repeated episodes of ventricular and supraventricular arrhythmia, including radiofrequency ablation performed at the age of 14. Subsequently Danon disease was confirmed by genetic testing. At the age of 22 - a cardioverter-defibrillator was implanted due to ventricular tachycardia and because of progression of chronic heart disease (NYHA class IV) the Heart Mate3 LVAD was implanted. Antithyroid antibodies (TSH receptor antibodies, anti-thyroid peroxidase antibodies) were negative in both patients. They had no personal or family history of thyroid disease. Both patients had no exposure to iodine-containing contrast media, Amiodarone, or iodine supplementation over the past two years. Thyroid ultrasound findings were similar for both - mild diffuse changes in the thyroid gland that could be consistent with chronic autoimmune thyroiditis. Thiamazole 30 mg daily was initiated without improvement. The female patient was evaluated to exclude struma ovarii. Possible iodine sources were reviewed again, and it was determined that Povidone-iodine solution was used for the Heart Mate3 LVAD entry point disinfection daily. Povidone-iodine was discontinued for both patients, and Thiamazole therapy 30 mg daily was continued for one more month and then decreased to 10 mg daily. Following this, both patients felt better, their symptoms of hyperthyroidism settled. A gradual improvement and normalization of thyroid hormone tests was observed within two months and Thiamazole was discontinued. We hypothesize that using Povidone-iodine long-term could cause iodine overdose and hyperthyroidism.