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A case of triple seronegative myasthenia gravis with Graves' disease ameliorated after the removal of enlarged thymus with elevated uptake in fluorine‐18 fluorodeoxyglucose positron emission tomography
Author(s) -
Matsumoto Namiko,
Omote Yoshio,
Nakano Yumiko,
Takemoto Mami,
Hishikawa Nozomi,
Sato Kota,
Ohta Yasuyuki,
Yamashita Toru,
Toji Tomohiro,
Abe Koji
Publication year - 2020
Publication title -
neurology and clinical neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.125
0ISSN - 2049-4173
DOI - 10.1111/ncn3.12414
Subject(s) - myasthenia gravis , medicine , repetitive nerve stimulation , thymectomy , positron emission tomography , acetylcholine receptor , fluorodeoxyglucose , autoantibody , graves' disease , endocrinology , pathology , thyroid , gastroenterology , nuclear medicine , antibody , receptor , immunology
We report on a 35‐year‐old woman who complained of myasthenia in ocular, bulbar, and limb muscles, but who was negative for antibodies against acetylcholine receptor, muscle‐specific kinase, or low‐density lipoprotein receptor‐related protein 4, accompanied by the suppression of thyroid‐stimulating hormone with elevated free T3 and free T4. Administration of edrophonium significantly ameliorated blepharoptosis, and electromyography revealed 13.9% waning after 3 Hz repetitive stimulation in the left accessory nerve. Thus, she was suspected of having triple seronegative myasthenia gravis or thyrotoxic myasthenia. She was remitted after the resection of her enlarged thymus with an elevated uptake in fluorine‐18 fluorodeoxyglucose positron emission tomography, suggesting an unknown autoimmune target that escaped detection by current autoantibody screens. Consequently, thymectomy may still be effective in patients with seronegative MG plus hyperthyroidism.