Alterações cognitivas em crianças com hipotireoidismo subclínico: revisão sistemática

Abstract

Introduction: Subclinical hypothyroidism is a condition in which the levels of the thyroid-stimulating hormone – TSH- are increased, but the levels of the thyroid hormones – thyroxine (T4) and triiodothyronine (T3) are normal. Subclinical thyroidism has high prevalence in the general population and can cause many alterations in the body, among them in the cognition. Objective: To investigate, through systematic review of literature, what neuropsychological alterations can be found in individuals in the pediatric age group with subclinical hypothyroidism. Metodology: A systematic review of literature was performed to search for scientific papers in the data bases PubMed, Web of Science, Scopus, Thomson Reuters, Eighteenth Century Collections Online, Begell House Digital Library, Lilacs and EmBase concluding in November, 2016. There was no restriction of language or period. Inclusion criteria: studies with children and adolescents with subclinical hypothyroidism that had performed cognitive evaluation. The following descriptors were used: “subclinical hypothyroidism”, “subclinical thyroid disease”, “subclinical Hashimoto’s thyroiditis”, “subclinical Hashimoto’s disease”, “mild hypothyroidism” and “compensated hypothyroidism”. Bibliographic references, in text references and references found in previous systematic reviews of literature were also reviewed. Results and Discussion: A total of one hundred and eleven papers were found. From these, 104 were excluded after the application of inclusion and exclusion criteria. Seven studies were selected after reading the full text. Among the selected studies, one of them revealed better performance in cognitive tests in the group with subclinical hypothyroidism compared to the control group, one did not find statistic differences between the control group and experimental group and five of them revealed impairment of at least one of the cognitive domains in the group of children with subclinical hypothyroidism. The affected domains were attention, perception, language, memory and executive functions. Conclusions: Subclinical hypothyroidism has been associated to cognitive alterations in most of the evaluated papers, but additional randomized studies are necessary to evaluate the cognitive aspects of this condition.