Idiopathic and mild subclinical hypothyroidism in childhood: clinical management.

Subclinical hypothyroidism (SH) is a common clinical problem in children and adolescents, for which there are many controversial issues regarding natural course and management. Aim of this review is to report on the state of the art regarding these controversial points of idiopathic SH in pediatric age. We included in our search only full-length articles on natural history and treatment of SH in children with no associated diseases or genetic syndromes, thus identifying only 13 papers that were suitable for our analysis. According to the results of these retrospective or longitudinal studies a persistently mild TSH elevation (between 5 and 10 mIU/L) in SH children with no underlying disease is unable to affect growth and bone maturation or body mass index (two studies) or cognitive function (one study). Moreover, the risk of a deterioration over time of thyroid function in the untreated cases with mild and idiophatic SH is only 12% (one study). Progression odds increase with increasing baseline TSH, with goiter presence and with positive anti-thyroid antibodies (two studies in children). Although no broad consensus exists on whether children with mild SH require L-T4 therapy, nevertheless, on the basis of the results of the majority of included studies, it can be concluded that L-T4 treatment is not indicated when TSH is repeatedly between 5 and 10 mIU/L and an underlying disease has been excluded. By contrast, treatment is suitable in the cases with TSH>10 mIU/L and/or an underlying disease.