title: The prevalence of transient thyrotoxicosis after antithyroid drug therapy in patients with Graves' disease.
abstract: BACKGROUND
  Although transient thyrotoxicosis occurring after antithyroid drug (ATD) withdrawal in patients with Graves' hyperthyroidism has been reported, the prevalence of transient thyrotoxicosis after ATD therapy is as yet unknown. When patients with transient hyperthyroidism are mistakenly regarded as recurrences, they receive unnecessary therapy. The aim of this study was to investigate the prevalence of transient thyrotoxicosis after ATD withdrawal.
  
  
  METHODS
  We selected 110 consecutive patients with Graves' disease whose ATD therapy was stopped from December 2002 to September 2004 prospectively. Patients were observed for more than 1 year after ATD withdrawal, and 12 patients dropped out. Serum levels of free thyroxine (FT(4)), thyrotropin, and thyrotropin-binding inhibitor immunoglobulin were measured at ATD withdrawal, and 3, 6, and 12 months after withdrawal. When the patients showed mild thyrotoxicosis (serum FT(4) level of less than 3.00 ng/dL), we followed them up for 1 month without medication.
  
  
  RESULTS
  The remission rate of the study group was 61.8% (68/110). Twenty-eight patients became euthyroid after transient thyrotoxicosis, equivalent to 41.2% of the remission patients. Eight of 28 patients showed overt thyrotoxicosis, and the rest subclinical thyrotoxicosis. Transient thyrotoxicosis occurred mostly 3-6 months after ATD withdrawal.
  
  
  CONCLUSIONS
  Transient thyrotoxicosis after ATD withdrawal in patients with Graves' disease is not a rare phenomenon. Clinicians should be aware that the recurrence of Graves' disease after the withdrawal of ATD may be transient.
authors.affiliation: Kuma Hospital, 8-2-35, Shimoyamate-dori, Chuo-ku, Kobe 650-0011, Japan. kubota@kuma-h.or.jp
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Kubota
authors.forename: Kazuna
authors.initials: K
authors.lastname: Takata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Arishima
authors.forename: Hidemi
authors.initials: H
authors.lastname: Ohye
authors.forename: Eijun
authors.initials: E
authors.lastname: Nishihara
authors.forename: Takumi
authors.initials: T
authors.lastname: Kudo
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ito
authors.forename: Shuji
authors.initials: S
authors.lastname: Fukata
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Amino
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
mesh_terms: D000328:Adult; D013956:Antithyroid Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001323:Autoantibodies / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006111:Graves Disease / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D018828:Immunoglobulins, Thyroid-Stimulating; D008297:Male; D008713:Methimazole / Q000009:adverse effects* / Q000627:therapeutic use; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012008:Recurrence; D013375:Substance Withdrawal Syndrome; D013971:Thyrotoxicosis / Q000097:blood / Q000139:chemically induced* / Q000453:epidemiology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D013997:Time Factors
chemical_list: D013956:Antithyroid Agents; D001323:Autoantibodies; D018828:Immunoglobulins, Thyroid-Stimulating; C094372:thyrotropin-binding inhibitory immunoglobulin; D008713:Methimazole; D013972:Thyrotropin; D013974:Thyroxine