Children With Congenital Hypothyroidism: Long-Term Intellectual Outcome After Early High-Dose Treatment

Abstract

ABSTRACT:We aim to determine long-term intellectual outcome of adolescents with early high-dose treated congenital hypothyroidism (CH). Sixty-three prospectively followed children with CH were assessed at age of 14 y with the Wechsler Intelligence Scale for Children-Revised and compared with 175 healthy controls. Median age at onset of treatment was 9 d (range 5-18 d) and median starting dose of levothyroxine (L-T4) was 14.7 g/kg/d (range 9.9 -23.6 g/kg/d). Full-scale intelligence quotient (IQ) was significantly lower than in controls after adjustment for socioeconomic status (SES) and gender (101.7 versus 111.4; p Ͻ 0.0001). Children with athyreosis had a lower performance IQ than those with dysgenesis (adjusted difference 7.6 IQ scores, p Ͻ 0.05). Lower initial thyroxine (T4) levels correlated with poorer IQ (r ϭ 0.27, p ϭ 0.04). Lower SES was associated with poorer IQ, in particular in children with CH (interaction, p ϭ 0.03). Treatment during childhood was not related to IQ at age 14 y. Adolescents with CH manifest IQ deficits when compared with their peers despite early high-dose treatment and optimal substitution therapy throughout childhood. Those adolescents with athyreosis and lower SES are at particular risk for adverse outcome. Therefore, early detection of intellectual deficits is mandatory in children with CH. (Pediatr Res 65: 242-248, 2009)

Risk factors for neurodevelopmental deficits in congenital hypothyroidism after early substitution treatment

“…Parental socioeconomic status (SES) was estimated based on parental occupation and maternal education [2,19]. SES scores ranged from 2 (lowest SES) to 12 (highest SES).…”

“…Recent reports about L-T 4 starting dose gave contradictory results [2,3]. In a review of ten studies that examined the effects of different starting L-T 4 doses on psychometric outcome, two reported no effect, six reported a higher IQ with higher starting doses, and another two reported a higher IQ with lower starting doses [22].…”

Wrodzona niedoczynność tarczycy — polskie rekomendacje dotyczące leczenia, monitorowania terapii i badania przesiewowego w specjalnych kategoriach noworodków z wysokim ryzykiem niedoczynności tarczycy

“…The initiation of treatment in the first two weeks of life gives the child a chance for normal intellectual and physical development [8][9][10]. In the most common primary hypothyroidism, levothyroxine preparations (L-T4) are considered to be the most effective.…”

“…Rozpoczęcie leczenia w ciągu pierwszych 2 tygodni życia daje dziecku szansę na prawidło-wy rozwój intelektualny i fizyczny [8][9][10]. W najczęściej występującej, pierwotnej niedoczynności tarczycy uważa się za najkorzystniejsze podawanie preparatów lewoskrętnej tyroksyny (L-T4).…”

The treatment and monitoring of the therapy of congenital hypothyroidism

“…Rozpoczęcie leczenia w ciągu pierwszych dwóch tygodni życia daje dziecku szansę na prawidłowy rozwój intelektualny i fizyczny [1][2][3]. W najczęściej występującej pierwotnej niedoczynności tarczycy uważa się za najkorzystniejsze podawanie preparatów lewoskrętnej tyroksyny (L-T4).…”