title: Neonatal hyperthyrotropinemia: population characteristics, diagnosis, management and outcome after cessation of therapy.
abstract: BACKGROUND
  Neonatal hyperthyrotropinaemia (HT), defined by elevated TSH and normal T(4), is either transient or persistent. The eventual outcome of neonatal HT is unpredictable and the management of HT patients is controversial. We assessed perinatal parameters and diagnostic measures that may distinguish between transient and persistent HT, compared with congenital hypothyroidism (CH). We also aimed to recommend optimal treatment in these forms of thyroid impairment.
  
  
  METHODS
  A multi-centre, retrospective study was conducted in six paediatric endocrinology units. Forty-three HT patients and 83 CH patients were included in the study. Measurements We evaluated differences in birth weight (BW), gestational age (GA), modes of diagnosis, screening and confirmatory T(4) and TSH levels, thyroid imaging results and optimal thyroxine doses between HT and CH and between the two forms of HT.
  
  
  RESULTS
  Newborns with HT had lower BW and GA than those with CH. Transient (n = 18) and persistent HT (n = 25) patients were indistinguishable by most parameters, but those with persistent HT had a higher prevalence of abnormal thyroid imaging (69%vs 8%; P = 0.005). During treatment, 79% and 55% of transient and persistent HT patients respectively experienced elevated levels of free T(4.) Although most HT patients were reevaluated after 2.5 years, six transient HT patients stopped therapy and showed full recovery within the first year of life.
  
  
  CONCLUSIONS
  We recommend obtaining thyroid imaging to distinguish between the two forms of HT. Adherence to recommended doses of thyroxine and probably early cessation of therapy in transient HT can prevent iatrogenic hyperthyroidism in these patients.
authors.affiliation: Pediatric Endocrinology Unit, Kaplan Medical Center, Rehovot, Israel. amzung2@bezeqint.net
authors.forename: Amnon
authors.initials: A
authors.lastname: Zung
authors.forename: Yardena
authors.initials: Y
authors.lastname: Tenenbaum-Rakover
authors.forename: Shiri
authors.initials: S
authors.lastname: Barkan
authors.forename: Aaron
authors.initials: A
authors.lastname: Hanukoglu
authors.forename: Eli
authors.initials: E
authors.lastname: Hershkovitz
authors.forename: Orit
authors.initials: O
authors.lastname: Pinhas-Hamiel
authors.forename: Tzvy
authors.initials: T
authors.lastname: Bistritzer
authors.forename: Zvi
authors.initials: Z
authors.lastname: Zadik
mesh_terms: D001724:Birth Weight; D003409:Congenital Hypothyroidism / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology* / Q000378:metabolism; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000378:metabolism / Q000473:pathology; D013972:Thyrotropin / Q000378:metabolism; D013974:Thyroxine / Q000378:metabolism / Q000627:therapeutic use
chemical_list: D013972:Thyrotropin; D013974:Thyroxine