Early diagnosis and treatment of congenital hypothyroidism are the main goals of the neonatal screening programs. A retrospective analysis was carried out to assess the characteristics and etiologies of congenital transient hypothyroidism (CTH) in the Newborn Screening Program of the State of Minas Gerais, Brazil. To reach a diagnosis of CTH, altered screening and serum confirmatory T4 and TSH tests and normal serum free T4 and TSH at 4 and 8 weeks after the withdrawal of levothyroxine were used. We studied 21 children with CTH who represented 4.23% of the whole group with detected hypothyroidism and followed them up in the Screening Program. These patients received LT4 therapy for a variable period of one month to three years. Serum confirmatory TSH levels varied from 10.4 to 583.4µUI/mL. Maternal antibodies, TRAB and anti-TPO, were associated to CTH in two children and iodine overload in one of them. We concluded that CTH is an important component in neonatal screening and hormonal treatment during the first months of the life is essential. The TSH initial levels are not relevant to determine whether the thyroid dysfunction is transient or permanent.
Congenital hypothyroidism; Neonatal hypothyroidism; Transient hypothyroidism
