title: Development of hyperthyroidism following primary hypothyroidism: a case report.
abstract: Development of hyperthyroidism following primary hypothyroidism is uncommon, and only a few documented cases have been reported. Alterations in thyroid-stimulating hormone receptor antibodies in serum are currently considered to play the main role in the pathophysiology, but the exact mechanism is still unknown. Here, we report the case of a 60-year-old man with disturbed consciousness due to hyponatremia. Thyroid function tests showed primary hypothyroidism with a high anti-microsomal antibody titer (1:6,400). The patient experienced weight loss and exophthalmos 6 years later. Serum thyroid hormone levels were increased and thyroxine treatment was discontinued, but the patient remained thyrotoxic 2 months later. 131I thyroid uptake was 40.9% at 24 hours, and bilateral thyroid lobes were not enlarged with diffuse radioactivity. Six months later, the patient was still thyrotoxic and therapy with methimazole 10 mg/day was started. He is now taking methimazole and is euthyroid.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: Yueh-Hua
authors.initials: YH
authors.lastname: Chung
authors.forename: Horng-Yih
authors.initials: HY
authors.lastname: Ou
authors.forename: Ta-Jen
authors.initials: TJ
authors.lastname: Wu
mesh_terms: D001323:Autoantibodies / Q000097:blood; D006801:Humans; D006980:Hyperthyroidism / Q000209:etiology*; D007037:Hypothyroidism / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011989:Receptors, Thyrotropin / Q000276:immunology
chemical_list: D001323:Autoantibodies; D011989:Receptors, Thyrotropin