title: Thyroid function in children and adolescents with Hashimoto's thyroiditis after l-thyroxine discontinuation.
abstract: OBJECTIVE
  Thyroid function may recover in patients with Hashimoto's thyroiditis (HT).
  
  
  METHODS
  To investigate thyroid function and the need to resume l-thyroxine treatment after its discontinuation.
  
  
  METHODS
  Nine Italian pediatric endocrinology centers.
  
  
  METHODS
  148 children and adolescents (25 m and 123 f) with HT on treatment with l-thyroxine for at least one year.
  
  
  METHODS
  Treatment was discontinued in all patients, and serum TSH and fT4 concentrations were measured at the time of treatment discontinuation and then after 2, 6, 12 and 24 months. Therapy with l-thyroxine was re-instituted when TSH rose >10 U/L and/or fT4 was below the normal range. The patients were followed up when TSH concentrations were between 5 and 10 U/L and fT4 was in the normal range.
  
  
  RESULTS
  At baseline, TSH was in the normal range in 139 patients, and was between 5 and 10 U/L in 9 patients. Treatment was re-instituted after 2 months in 37 (25.5%) patients, after 6 months in 13 patients (6.99%), after 12 months in 12 patients (8.6%), and after 24 months in an additional 3 patients (3.1%). At 24 months, 34 patients (34.3%) still required no treatment. TSH concentration >10 U/L at the time of diagnosis was the only predictive factor for the deterioration of thyroid function after l-thyroxine discontinuation.
  
  
  CONCLUSIONS
  This study confirms that not all children with HT need life-long therapy with l-thyroxine, and the discontinuation of treatment in patients with a TSH level <10 U/L at the time of diagnosis should be considered.
authors.affiliation: PediatricsRegional Hospital, Bolzano, Italy giorgio.radetti@gmail.com.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Radetti
authors.affiliation: PediatricsUniversity Federico II, Naples, Italy.
authors.forename: Mariacarolina
authors.initials: M
authors.lastname: Salerno
authors.affiliation: Pediatric EndocrinologyOspedale Pedatrico Microcitemico 'A. Cao' - AOB Cagliari, Cagliari, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Guzzetti
authors.affiliation: Pediatric EndocrinologyBambino Gesù Children Hospital, Roma, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Cappa
authors.affiliation: Divisione di Endocrinologia PediatricaOspedale Infantile Regina Margherita, Torino, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Corrias
authors.affiliation: Department of PediatricsUniversity of Bologna, Bologna, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cassio
authors.affiliation: Department of PediatricsUniversity of Pisa, Pisa, Italy.
authors.forename: Graziano
authors.initials: G
authors.lastname: Cesaretti
authors.affiliation: Paediatric DepartmentGaslini Hospital, Genova, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Gastaldi
authors.affiliation: Unit of Internal Medicine and EndocrinologyFondazione Salvatore Maugeri I.R.C.C.S., ISPESL Laboratory for Endocrine Disruptors, University of Pavia, Pavia, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Rotondi
authors.affiliation: PediatricsRegional Hospital, Bolzano, Italy.
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Lupi
authors.affiliation: Department of BiostatisticsRegional Hospital, Bolzano, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Fanolla
authors.affiliation: Department of PediatricsVita-Salute San Raffaele University, Milan, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Weber
authors.affiliation: Pediatric EndocrinologyOspedale Pedatrico Microcitemico 'A. Cao' - AOB Cagliari, Cagliari, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Loche
keywords: Hashimoto’s thyroiditis; autoimmune thyroiditis; children; l-thyroxine treatment; subclinical hypothyroidism