title: Elevated thyroid peroxidase antibodies with encephalopathy in MELAS syndrome.
abstract: Both the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome) and Hashimoto's encephalopathy can present with nonspecific encephalopathy. Hashimoto's encephalopathy is an association of steroid-responsive encephalopathy with elevated thyroid peroxidase antibodies. Steroid-responsive encephalopathy, however, is not characteristic of the MELAS syndrome, which typically presents with stroke-like episodes and lactic acidosis in cerebrospinal fluid and blood. Here, a patient is described with goiter, recurrent encephalopathy and elevated thyroid peroxidase antibodies who apparently responded to steroid therapy; however, magnetic resonance imaging was atypical for Hashimoto's encephalopathy, and she was diagnosed with MELAS syndrome. This syndrome can present with apparent steroid-responsive encephalopathy and elevated thyroid peroxidase antibodies, mimicking Hashimoto's encephalopathy, and should be suspected if lactic acidosis is present and typical features are detected on magnetic resonance imaging.
authors.affiliation: Pediatric Neurology Service, Department of Pediatric Medicine, KK Women's and Children's Hospital, Singapore. derrickchanws@gmail.com
authors.forename: Derrick W S
authors.initials: DW
authors.lastname: Chan
authors.forename: C C Tchoyoson
authors.initials: CC
authors.lastname: Lim
authors.forename: Stacey K H
authors.initials: SK
authors.lastname: Tay
authors.forename: Chew-Thye
authors.initials: CT
authors.lastname: Choong
authors.forename: Huan Kee
authors.initials: HK
authors.lastname: Phuah
mesh_terms: D000140:Acidosis, Lactic / Q000209:etiology; D001323:Autoantibodies / Q000097:blood*; D001921:Brain / Q000473:pathology; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D050031:Hashimoto Disease / Q000150:complications* / Q000276:immunology*; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology*; D017241:MELAS Syndrome / Q000150:complications*; D009682:Magnetic Resonance Spectroscopy; D020521:Stroke / Q000209:etiology
chemical_list: D001323:Autoantibodies; D007453:Iodide Peroxidase