Our patient is a twenty-four-year-old female with a sixteen-year history of HT-related hypothyroidism on oral levothyroxine 100 mcg once daily. She complained of occasional palpitations, nervousness, weight loss, and irregular menses. Thyrotoxicosis was confirmed with a thyroid function test, and levothyroxine dose was reduced. However, the patient continued to exhibit thyrotoxic symptoms even after completely stopping levothyroxine. On examination, the patient was calm but tachycardic and afebrile, and her blood pressure was 116/90 mmHg, weight was 58 kg, and BMI was 21.8. She was noted to have peripheral tremors. Her thyroid exam revealed the presence of diffuse nontender goiter, with no palpable nodules. Eye examination was only remarkable for mild exophthalmos, and there was no evidence of dermopathy.\nThyroid function revealed depressed TSH <0.01 mIU/L (0.3–4.2) and high T4 26.4 pmol/L (11.6–21.9) (). Based on the persistence of symptoms despite stopping thyroid hormone supplementations and the presence of ophthalmopathy elements, the rare shift to GD was suspected. Autoimmune workup revealed a strong positive Anti-TSH Receptor (Anti-TSHR) titer, in addition to persistent positivity of previously positive thyroid peroxidase antibody (TPO Ab) and an increasing titer of Antithyroglobulin Ab (). Thyroid ultrasound revealed slight enlargement of the right lobe and increased vascularity in both lobes. Radioactive iodine uptake scan (RAIU) showed diffuse radiotracer uptake more prominent in the right thyroid lobe (). Those findings kept with the shift to GD.\nThe patient received suppressive therapy with oral carbimazole 20 mg once daily and propranolol. A subsequent follow-up three months later showed normalization of thyroid function and improvement in clinical status.
A 60-year-old lady, presented with tremulousness of hands for 1 month and palpitation with excessive sweating for 3 months. She had a history of weight loss for 6 months, and gradually enlarging neck swelling for 3 years. She was nervous, irritable, and emotionally labile. Her weight was 46 kg, BMI 17, afebrile, pulse rate: 110/min/regular, blood pressure: 140/56 mm of Hg. Her thyroid gland was symmetrically enlarged, firm in consistency, nodular/lobular surface and mildly tender without any bruit. Palms were warm and sweaty with fine tremor in hands. All reflexes were exaggerated. There were no occular manifestations.\nInitial thyroid function tests (TFT) revealed high T3: 3.80 ng/ml (0.80-2.10), T4: 12.40 ug/dl (5.10-12) with a low TSH: 0.20 mU/L (0.70-5). Her TSH receptor antibody (TSAb): 25 U/L (Normal [nl.] <1), anti TPO antibody: 374 IU/ml (nl. <35) and thyroglobulin antibody: 268 IU/ml (nl. <65) were all strongly positive. Complete hemogram and ESR-18 mm/h (nl.-1-25) were normal. Ultrasonogram of thyroid revealed an enlarged gland with hypoechoic parenchyma with fibrous septa.99mTc pertechnetate scan (Tc99m scan) revealed enlarged thyroid gland with diffusely increased uptake of radiocontrast: 17% (nl. 0.4-4%) with some patchy defects in both lower poles. Thyroid FNAC showed sheets of Hurthle cells with abdunce of lymphocytes and sheets of regular follicular cells, indicating HT. She was observed on beta blockers. Repeat TFT, 3 months later showed: T3: 4.20 ng/ml, T4: 14.40 ug/dl, TSH: 0.001 μU. Repeat 99mTc pertechnetate scan was done, which again revealed enlarged thyroid gland with diffusely increased uptake of radiocontrast: 21% (nl. 0.4-4%) with same patchy defects in both lower poles. Antithyroid medication carbimazole was started.