Hashimoto's Encephalopathy Presenting with Smoldering Limbic Encephalitis

Masahiro Nagano; Katsuya Kobayashi; Mayumi Yamada-Otani; Akira Kuzuya; Riki Matsumoto; Jiro Oita; Makoto Yoneda; Akio Ikeda; Ryosuke Takahashi

doi:10.2169/internalmedicine.1289-18

CASE REPORTS

Hashimoto's Encephalopathy Presenting with Smoldering Limbic Encephalitis

Masahiro Nagano, Katsuya Kobayashi, Mayumi Yamada-Otani, Akira Kuzuya, Riki Matsumoto, Jiro Oita, Makoto Yoneda, Akio Ikeda, Ryosuke Takahashi

Author information

Masahiro Nagano
Department of Neurology, Kyoto University Graduate School of Medicine, Japan
Katsuya Kobayashi
Department of Neurology, Kyoto University Graduate School of Medicine, Japan
Mayumi Yamada-Otani
Department of Neurology, Kyoto University Graduate School of Medicine, Japan
Akira Kuzuya
Department of Neurology, Kyoto University Graduate School of Medicine, Japan
Riki Matsumoto
Department of Neurology, Kyoto University Graduate School of Medicine, Japan
Jiro Oita
Department of Neurology, Shimizu Hospital, Japan
Makoto Yoneda
Faculty of Nursing and Social Welfare Sciences, Fukui Prefectural University, Japan
Akio Ikeda
Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, Japan
Ryosuke Takahashi
Department of Neurology, Kyoto University Graduate School of Medicine, Japan

Keywords: Hashimoto's encephalopathy, FDG-PET, video EEG, autoimmune limbic encephalitis, anti-NAE antibody

JOURNAL OPEN ACCESS

2019 Volume 58 Issue 8 Pages 1167-1172

DOI https://doi.org/10.2169/internalmedicine.1289-18

Details

Abstract

Hashimoto's encephalopathy (HE) is a steroid-responsive autoimmune encephalopathy associated with Hashimoto thyroiditis. We herein report a case of HE manifesting "smoldering" limbic encephalitis with persisting symptoms and abnormalities on examinations. Although our patient experienced partial clinical remission after treatment, hippocampal hypermetabolism on [¹⁸F] fluorodeoxyglucose positron emission tomography (FDG-PET) and subclinical seizures on video electroencephalography persisted. Hypermetabolism on FDG-PET was improved by additional prednisolone therapy. Thus, as with other autoimmune limbic encephalitis cases, HE can take a course of "smoldering" encephalitis. FDG-PET and electroencephalogram findings can reflect the disease activity degree in such patients, although with certain neurophysiological and biochemical distinctions.

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