Subclinical hypothyroidism in children: updates for pediatricians

Subclinical hypothyroidism (SH) is defined as serum thyroid-stimulating hormone (TSH) above the upper limit of the reference range in the presence of normal free T4 concentrations. Depending on the degree of TSH elevation, SH could be defined as mild (TSH, 4.5–10 mIU/L) or severe (TSH>10 mIU/L). While there is a general consensus to treat children with serum TSH levels above 10 mU/L, the management of the mild form is uncertain and should be individualized. In this mini-review, we present a brief review of SH in children based on extensive literature review and long-standing clinical experience. This review provides the prevalence, causes, clinical presentation, consequences, investigation, and up-to-date therapeutic approach of SH in children. Generally, the purpose of the review is to provide pediatricians with an update of this common and continuously evolving condition.