Original Article

European Journal of Nuclear Medicine and Molecular Imaging

, Volume 34, Issue 9, pp 1498-1503

First online:

Thyroid scintigraphy and perchlorate test after recombinant human TSH: a new tool for the differential diagnosis of congenital hypothyroidism during infancy

  • Laura FugazzolaAffiliated withDepartment of Medical Sciences, University of Milan and Fondazione Policlinico IRCCS Email author 
  • , Luca PersaniAffiliated withDepartment of Medical Sciences, University of Milan and Istituto Auxologico Italiano
  • , Guia VannucchiAffiliated withDepartment of Medical Sciences, University of Milan and Fondazione Policlinico IRCCS
  • , Marco CarlettoAffiliated withDepartment of Nuclear Medicine, Fondazione Policlinico IRCCS
  • , Deborah MannavolaAffiliated withDepartment of Medical Sciences, University of Milan and Fondazione Policlinico IRCCS
  • , Maria Cristina VigoneAffiliated withCentro di Endocrinologia dell’Infanzia e dell’Adolescenza, Università Vita-Salute S. Raffaele
  • , Francesca CortinovisAffiliated withCentro di Endocrinologia dell’Infanzia e dell’Adolescenza, Università Vita-Salute S. Raffaele
  • , Luciano BeccariaAffiliated withPaediatric Unit, A. Manzoni Hospital
  • , Virgilio LongariAffiliated withDepartment of Nuclear Medicine, Fondazione Policlinico IRCCS
    • , Giovanna WeberAffiliated withCentro di Endocrinologia dell’Infanzia e dell’Adolescenza, Università Vita-Salute S. Raffaele
    • , Paolo Beck-PeccozAffiliated withDepartment of Medical Sciences, University of Milan and Fondazione Policlinico IRCCS

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Abstract

Purpose

Prompt initiation of l-thyroxine therapy in neonates with congenital hypothyroidism (CH) often prevents the performance of functional studies. Aetiological diagnosis is thus postponed until after infancy, when the required investigations are performed after l-thyroxine withdrawal. The aim of this study was to verify the efficacy and safety of new protocols for rhTSH (Thyrogen) testing during l-thyroxine replacement in the differential diagnosis of CH.

Methods

Ten CH patients (15–144 months old) were studied. Seven had neonatal evidence of gland in situ at the ultrasound examination performed at enrolment and received two rhTSH injections (4 μg/kg daily, i.m.) with 123I scintigraphy and perchlorate test on day 3. Three patients with an ultrasound diagnosis of thyroid dysgenesis received three rhTSH injections with 123I scintigraphy on days 3 and 4. TSH and thyroglobulin (Tg) determinations were performed on days 1, 3 and 4, and neck ultrasound on day 1.

Results

rhTSH stimulation caused Tg levels to increase in eight cases. Blunted Tg responses were seen in two patients with ectopia and hypoplasia. Interestingly, in two cases the association of different developmental defects was demonstrated. Perchlorate test revealed a total iodide organification defect in two patients, including one with a neonatal diagnosis of Pendred’s syndrome, who were subsequently found to harbour TPO mutations. rhTSH did not cause notable side-effects.

Conclusion

These new rhTSH protocols always resulted in accurate disease characterisation, allowing specific management and targeted genetic analyses. Thus, rhTSH represents a valid and safe alternative to l-thyroxine withdrawal in the differential diagnosis of CH in paediatric patients.

Keywords

Recombinant human TSH Congenital hypothyroidism Total iodide organification defect Thyroid scintigraphy Perchlorate test