Alterações do TSH em pacientes com síndrome de Down: uma interpretação nem sempre fácil Alterations of TSH in Down's syndrome patients: a hard interpretation

Abstract

OBJETIVO: Determinar as concentrações de hormônio estimulante da tireóide (TSH) e a presença de anticorpos antitireoperoxidase (anti-TPO) em pacientes com síndrome de Down (SD) atendidos no ambulatório do Hospital de Clínicas da Universidade Federal do Paraná. MÉTODOS: Foram incluídos no estudo 72 pacientes com SD, não aparentados e selecionados consecutivamente, com média de idade de 6,15 anos. Oitenta crianças sadias, pareadas com os pacientes, foram utilizadas como controles. Em todas as amostras foram determinadas as concentrações séricas de TSH e de anti-TPO, através do método de dosagem imunométrica. RESULTADOS: Trinta pacientes com SD (42,9%) apresentaram alterações nas concentrações de TSH, sendo que 4,3% tinham valores menores que 0,5µUI/ml e 38,6%, valores superiores a 5µUI/ml (5,1 a 22) (média de 5,56 ± 4,18µUI/ml). Nos controles, a concentração média de TSH foi 2,76µUI/ml (± 1,14), evidenciando-se um aumento significativo nos níveis de TSH nos pacientes com SD (p OBJECTIVE: To evaluate the thyroid stimulating hormone (TSH) levels and the presence of antithyroperoxidase antibody (anti-TPO) in Down’s syndrome (DS) patients from Hospital de Clínicas of Universidade Federal do Paraná (HC/UFPR). METHODS: Seventy-two DS patients, non-related and consecutively selected (mean age 6.15) were included in the study. Eighty matched healthy children were used as controls. The TSH measurement and the anti-TPO were determined by immunometric assay in all samples. RESULTS: Thirty patients with DS (42.9%) presented abnormal levels of TSH; 4.3% showed values below 0.5µIU/ml and 38.6% presented values higher than 5µIU/ml (range 5.1-22; mean 5.56 ± 4.18µIU/ml). The mean concentration of TSH in the controls was 2.76 ± 1.14µIU/ml, indicating a significant increase in TSH levels in the DS patients (p < 0.001). Similarly, a significant difference was observed in the anti-TPO positivity in the patients’ group (15.4%) when compared with the controls (0%; p < 0.001). In addition, the TSH levels of patients older than 9 years presented a significant increase (mean of 6.86 ± 4.6µIU/ml) when compared with the levels observed in patients younger than 9 years (mean of 5.24 ± 3.81µIU/ml; p = 0.006). The same pattern was observed in the positivity of anti-TPO (6/20 vs. 5/52; p = 0.041). CONCLUSIONS: The results demonstrated high prevalence of elevated TSH and anti-TPO in the patients from the DS ambulatory of HC/UFPR, with increased frequency in those older than 9 years. The data indicate that the evaluation of thyroid function in DS patients must receive special attention from health professionals who take care of these patients.

Keywords

• Síndrome de Down
• Tireoidites
• TSH
• Down’s syndrome
• Thyroiditis
• TSH