Sustained attention in school-age children with congenital hypothyroidism: Influence of episodes of overtreatment in the first three years of life

Neuropsychological Alterations in Patients with Congenital Hypothyroidism Treated with Levothyroxine: Linked Factors and Thyroid Hormone Hyposensitivity

Eighty-five percent of the studies of patients with congenital hypothyroidism (CH) treated with Levothyroxine (L-T₄) report neuropsychological sequelae throughout life. In neonates and infants, there is a deficit in sensorimotor skills (impaired balance). In preschool and elementary school children and adolescents, there are alterations in intellectual quotient (low scores), language (delayed phonological acquisition), memory (visual, verbal, visuospatial, visuoconstructive, autobiographical, and semantic), sensorimotor skills (impaired fine and gross motor control), and visuoconstructive–visuospatial domain (low scores in spatial location, block design, and object assembly). These neuropsychological domains are also affected in young adults, except for language (adequate verbal fluency) and visuoconstructive–visuospatial domain (no data). The onset and severity of neuropsychological sequelae in patients with treated CH depend on several factors: extrinsic, related to L-T₄ treatment and social aspects, and intrinsic, such as severity and etiology of CH, as well as structural and physiological changes in the brain. In this review, we hypothesized that thyroid hormone hyposensitivity (THH) could also contribute to neuropsychological alterations by reducing the effectiveness of L-T₄ treatment in the brain. Thus, further research could approach the THH hypothesis at basic and clinical levels to implement new endocrinological and neuropsychological therapies for CH patients.

Levothyroxine treatment for congenital hypothyroidism based on thyroid function: a 10-year clinical retrospective study

OBJECTIVE

To explore the appropriate dosage of levothyroxine treatment for congenital hypothyroidism patients with different thyroid stimulating hormone (TSH) levels.

METHODS

A total of 116 patients, who were regularly followed-up in our endocrine clinic from January 2010 to December 2020, were divided into four groups based on their thyroid function (group A: TSH ≥ 100 mIU/L, group B: TSH ≥ 20, and < 100, group C: TSH > 4.6 mIU/L and < 20 mIU/L with free thyroxine (FT4) < 6.6 pmol/L, and group D: TSH > 4.6 mIU/L and < 20 mIU/L with FT4 > 6.6 pmol/L). The initial dosage of levothyroxine was individualized for each patient based on their TSH level and then adjusted according to their thyroid function at every follow-up time point. The levothyroxine dosage at each time point was compared between the groups, and thyroid function and physical and neurological development after treatment were also compared.

RESULTS

After individualized dosage adjustment, all patients achieved normal thyroid function. Although there were statistical differences in neurological development between the four groups (p < 0.05), development was within the normal range for all groups.

CONCLUSION

An individualized levothyroxine dosage can provide the same therapeutic effect compared to the recommended dosage. This strategy may also reduce the risk of a drug overdose.

Basal Serum Thyroxine Level should Guide Initial Thyroxine Replacement Dose in Neonates with Congenital Hypothyroidism

OBJECTIVE

Initial high-dose sodium levothyroxine (Na-LT₄) (10-15 μg/kg/day) replacement for primary congenital hypothyroidism (CH) is recommended in guidelines. However, high-dose Na-LT₄ risks iatrogenic hyperthyroidism. The aim of this study was to investigate the normalizing effect of varying initial doses of Na-LT₄ on serum thyroid hormone levels.

METHODS

Fifty-two patients were analyzed retrospectively. The patients were classified into mild (27/51.9%), moderate (11/21.1%) and severe (14/26.9%) CH, based on initial free thyroxine (fT₄) levels. Time taken to achieve target hormone levels was compared within groups.

RESULTS

Initial mean Na-LT₄ doses for mild, moderate and severe disease were 6.9±3.3, 9.4±2.2 and 10.2±2 μg/kg/day. Serum fT₄ levels reached the upper half of normal range (>1.32 ng/dL) in a median of 16, 13 and 16 days in patients with mild, moderate and severe CH with the mean time from initial treatment to first control visit of 14.8±6 days (range 1-36). There was no significant difference in terms of time to achieve target fT₄ hormone levels according to disease severity (p=0.478). Seven (25.9%), eight (72.7%) and eight (57.1%) patients experienced hyperthyroxinemia (serum fT₄ >1.94 ng/dL) in the mild, moderate, and severe CH groups at the first visit, respectively (p=0.016).

CONCLUSION

Not all patients diagnosed with CH require high-dose Na-LT₄. Initial dose of Na-LT₄ may be selected on the basis of pre-treatment thyroid hormone levels. Some patients with moderate and severe CH, experienced iatrogenic hyperthyroxinemia even though the dose was close to the lower limit of the recommended range in guidelines. We suggest that lower initial doses may be appropriate with closer follow-up within the first week.

[Neonatal screening for congenital hypothyroidism]

Congenital hypothyroidism (CH) is the leading cause of preventable mental retardation. It is mainly due to thyroid dysgenesis or dyshormonogenesis with normally located gland, and detected at birth in developed countries by systematic neonatal screening. The early treatment of patients with CH has successfully improved the prognosis and management of this disease. An increase in the incidence of congenital hypothyroidism with a normally located gland has been reported worldwide over the last three decades. The etiology of CH with a normally located gland remains elusive and about half of them demonstrate spontaneous resolution of CH within a few months (transient CH). They highlight the need to reevaluate thyroid function during follow-up.

Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines Update-An ENDO-European Reference Network Initiative Endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology

Background: An ENDO-European Reference Network (ERN) initiative was launched that was endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology with 22 participants from the ENDO-ERN and the two societies. The aim was to update the practice guidelines for the diagnosis and management of congenital hypothyroidism (CH). A systematic literature search was conducted to identify key articles on neonatal screening, diagnosis, and management of primary and central CH. The evidence-based guidelines were graded with the Grading of Recommendations, Assessment, Development and Evaluation system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion. Summary: The recommendations include the various neonatal screening approaches for CH as well as the etiology (also genetics), diagnostics, treatment, and prognosis of both primary and central CH. When CH is diagnosed, the expert panel recommends the immediate start of correctly dosed levothyroxine treatment and frequent follow-up including laboratory testing to keep thyroid hormone levels in their target ranges, timely assessment of the need to continue treatment, attention for neurodevelopment and neurosensory functions, and, if necessary, consulting other health professionals, and education of the child and family about CH. Harmonization of diagnostics, treatment, and follow-up will optimize patient outcomes. Lastly, all individuals with CH are entitled to a well-planned transition of care from pediatrics to adult medicine. Conclusions: This consensus guidelines update should be used to further optimize detection, diagnosis, treatment, and follow-up of children with all forms of CH in the light of the most recent evidence. It should be helpful in convincing health authorities of the benefits of neonatal screening for CH. Further epidemiological and experimental studies are needed to understand the increased incidence of this condition.

Experticia y cognición. Exploración de funciones cognitivas verbales y visoespaciales en arquitectos y psicólogos

Diversas investigaciones han advertido que el ejercicio de algunas profesiones puede conllevar efectos moduladores en la estructura cerebral y el funcionamiento cognitivo. Se presentan los resultados de un estudio exploratorio transversal referente a las modificaciones que las experticias en arquitectura (N = 41, edad: X = 39, DE = 10) y en psicología (N = 40, edad: X = 35, DE = 7) producen sobre procesos cognitivos específicos. El objetivo general fue contribuir a la determinación de perfiles cognitivos diferenciales. Los arquitectos mostraron un mejor rendimiento en tareas que involucran la retención y manipulación de información visoespacial. No se hallaron diferencias significativas en la resolución de tareas verbales. Estos resultados sugieren que la experiencia en arquitectura podría conducir a un desempeño conductual mejorado en procesos cognitivos correspondientes a la memoria de trabajo visoespacial. Se discuten los alcances de la presente exploración y las instancias necesarias para la validación de estas observaciones. Se sugiere la realización de nuevos estudios que integren seguimiento longitudinal y tecnologías de neuroimagen.