Alteraciones del neurodesarrollo en pacientes con hipotiroidismo congénito: Recomendaciones para el seguimiento

Abstract

Congenital hypothyroidism (CH) is the most common cause of preventable cognitive disability worldwide. Generally, it is produced by an alteration in the embryogenesis of the thyroid gland or by an alteration in the synthesis of thyroid hormones, which determine that affected patients have low or absent thyroid hormone concentrations. The importance of this fact is that brain development during the first three years of life is highly dependent on thyroid hormones. Prior to the implementation of national neonatal screening programs around the world, 8 to 27% of children with CH had an IQ lower than 70. Nowadays, this percentage is close to 0 in countries that have implemented the program. In Chile, CH neonatal screening program achieved national coverage in 1996. Currently, the incidence of the disease in our country is 1: 3163. The degree of disability produced by CH not only depends on the time of detection of the disease and the prompt start of therapy, but also on an adequate monitoring. Despite screening programs, neurocognitive impairment in schoolchildren and teenagers with CH is still observed, reflected in lower scores in cognitive, language and gross motor assessments, receptive communication, expressive communication, fine motor and gross motor skills compared to healthy children. Also, lesser achievements in learning and language disorders are observed. The objective of this review is to update the information available on neurodevelopment of patients with CH.

Desempenho em habilidades motoras, comunicativas e cognitivas de crianças com hipotireoidismo congênito tratadas desde o período neonatal

“…Research has shown differences in the language skills of children with CH (9,(13)(14)(15)18,25) , although there are controversial results regarding the language of this population (16,17) . Bulus and Tiftik (17) found no statistically significant differences in language in a comparison between individuals with and without CH.…”

“…The literature points to this issue, stating that early diagnosis and treatment of CH are extremely important to prevent intellectual disability (7)(8)(9)15,20) . However, it also states that children with CH may present lower cognitive test results compared with their peers (7,12,18) . A study showed that children with CH, despite not presenting intellectual disabilities, had lower scores compared with siblings without metabolic disorders (12) .…”

“…However, although early screening programs for CH have proven effective in reducing intellectual disability, the key issue is identifying neurocognitive sequelae, even the subtlest ones, which may persist despite early treatment (2,(4)(5)(6)9,11,19) . Studies have reported that individuals with CH may present attention, memory, visuocognitive, visuospatial and psychomotor disorders (1,10,12,14,(18)(19)(20)24) . Yang et al (24) demonstrated that children with CH are more likely to present symptoms of attention-deficit hyperactivity disorder (ADHD).…”

“…Cognitive deficits have been observed in children, adolescents and adults with CH, especially in cases of late initiation of treatment and/or more severe hormonal alterations (12,(18)(19)(20) . Hormone deficiency in brain regions responsible for cognitive activities leads to perceptual changes (12) , which can interfere with information processing and impair language development.…”

“…Delays in the beginning of oral language production, comprehension difficulties, reduced vocabulary and morphosyntactic changes have been reported in children with CH (1,8,13,21,22) , as well as changes in behavior such as hyperactivity, impulsivity, sleep disorders, agitation, among others (1,10,14,19,23,24) , which may contribute to deficits in school learning and social integration of children. Motor impairment has also been reported with regards to delayed inhibition of primitive reflexes, alterations in static and dynamic balance and, especially, gross and fine motor coordination (14,15,17,18,25) .…”