A case of simultaneous occurrence of Graves’ disease and Hashimoto's thyroiditis
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.