title: Polyarthritis caused by methimazole in two Japanese patients with graves' disease.
abstract: In many countries, methimazole (MMI) therapy is the first-line treatment in children with Graves' disease (GD). The rate of side effects of antithyroid drugs (ATDs) in children has been reported to range between 6% and 35%. Of these side effects, polyarthritis is uncommon but serious, and can also develop as a part of the antineutrophil cytoplasmic antibody-associated vasculitis that is induced by ATDs. Here, we describe two GD girl patients aged 15 years and 11 years who developed polyarthritis. The onset of polyarthritis in these patients was 24 days and 28 days after the initiation of MMI therapy, respectively. MMI was suspected of causing the polyarthritis in the two patients and was withdrawn. The symptoms of polyarthritis disappeared rapidly following cessation of treatment. Subsequently, one patient was treated with 131I therapy and the other patient was subjected to thyroidectomy. Although it rarely occurs in pediatric GD patients, severe polyarthritis is a serious side effect of MMI and is an indication for prompt cessation of treatment.
authors.affiliation: Hokkaido University School of Medicine, Department of Pediatrics, Sapporo, Japan. E-mail: tajeari@med.hokudai.ac.jp.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nihei
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tada
authors.forename: Yuki
authors.initials: Y
authors.lastname: Naruse
authors.forename: Masako
authors.initials: M
authors.lastname: Izawa
authors.forename: Manji
authors.initials: M
authors.lastname: Kato
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okuno
authors.forename: Akie
authors.initials: A
authors.lastname: Nakamura
authors.forename: Katsura
authors.initials: K
authors.lastname: Ishizu
authors.forename: Takashi
authors.initials: T
authors.lastname: Hamajima
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tajima
mesh_terms: D000293:Adolescent; D013956:Antithyroid Agents / Q000009:adverse effects*; D001168:Arthritis / Q000139:chemically induced*; D002648:Child; D005260:Female; D006111:Graves Disease / Q000188:drug therapy*; D006801:Humans; D008713:Methimazole / Q000009:adverse effects*
chemical_list: D013956:Antithyroid Agents; D008713:Methimazole