title: Clinical characteristics of myeloperoxidase antineutrophil cytoplasmic antibody-associated vasculitis caused by antithyroid drugs.
abstract: BACKGROUND
  The clinical characteristics of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis caused by antithyroid drugs are still unclear because most reports describe only a small number of patients.
  
  
  OBJECTIVE
  The objective was to analyze a large number of patients with MPO-ANCA-associated vasculitis to determine the time of onset, the drug and dose taken, the clinical symptoms, the relationship between the clinical symptoms and the MPO-ANCA titer, and the incidence.
  
  
  METHODS
  We analyzed 92 patients in whom the adverse reaction of MPO-ANCA-associated vasculitis was reported to Chugai Pharmaceutical, a company that markets antithyroid drugs.
  
  
  RESULTS
  Of the 92 patients, 41 (44.6%) had single-organ failure, 32 (34.8%) had two-organ failure, 13 (14.1%), had three-organ failure, and two (2.2%) had four-organ failure. The number of organs involved was unknown in the other four patients (4.3%). The median time of onset was 42 months (range, 1-372 months) after starting drug treatment. The median dose at onset of MPO-ANCA-associated vasculitis was 15 mg/d (range, 2.5-45 mg/d) for methimazole and 200 mg/d (50-450 mg/d) for propylthiouracil. The severity and number of organs involved were not correlated with the MPO-ANCA titer. The incidence was between 0.53 and 0.79 patients per 10,000, and the ratio of the estimated incidences for methimazole and propylthiouracil was 1:39.2.
  
  
  CONCLUSIONS
  The time of onset of MPO-ANCA-associated vasculitis and the dose at onset varied. The severity and number of organs involved were not correlated with the MPO-ANCA titer, indicating a need for vigilance even when the MPO-ANCA titer is only weakly positive.
authors.affiliation: Ito Hospital, Internal Medicine, 4-3-6 Jigumae, Shibuya-ku, Tokyo, Japan. h-yoshimura@ito-hospital.jp
authors.forename: Jaeduk Yoshimura
authors.initials: JY
authors.lastname: Noh
authors.forename: Shigemitu
authors.initials: S
authors.lastname: Yasuda
authors.forename: Shotaro
authors.initials: S
authors.lastname: Sato
authors.forename: Masako
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Yo
authors.initials: Y
authors.lastname: Kunii
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Noguchi
authors.forename: Koji
authors.initials: K
authors.lastname: Mukasa
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Ito
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
authors.forename: Osamu
authors.initials: O
authors.lastname: Sugiyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nihojima
authors.forename: Masaru
authors.initials: M
authors.lastname: Okazaki
authors.forename: Shunji
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood / Q000502:physiology*; D013956:Antithyroid Agents / Q000009:adverse effects*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology*; D014657:Vasculitis / Q000209:etiology*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D013956:Antithyroid Agents; D009195:Peroxidase