Associations of TSH, free T3, free T4, and conversion ratio with incident hypertension: results from the prospective Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

ABSTRACT Objective: To evaluate the association of TSH, free T3 (FT3), free T4 (FT4), and conversion (FT3:FT4) ratio values with incident hypertension. Materials and methods: The study included data from participants of the ELSA-Brasil study without baseline hypertension. Serum TSH, FT4 and FT3 levels, and FT3:FT4 ratio values were assessed at baseline, and incident hypertension (defined by blood pressure levels ≥ 140/90 mmHg) was estimated over a median of 8.2 years of follow-up. The risk of incident hypertension was evaluated considering a 1-unit increase in TSH, FT4, FT3, and conversion ratio values and after dividing these variables into quintiles for further analysis using Poisson regression with robust variance. The results are presented as relative risks (RR) and 95% confidence intervals (CIs) before and after adjustment for multiple variables. Results: The primary analysis incorporated data from 5,915 euthyroid individuals, and the secondary analysis combined data from all euthyroid individuals, 587 individuals with subclinical hypothyroidism, and 31 individuals with subclinical hyperthyroidism. The rate of incident hypertension was 28% (95% CI: 27%-29.3%). The FT4 levels in the first quintile (0.18-1.06 ng/dL) were significantly associated with incident hypertension (RR: 1.03, 95% CI: 1.01-1.06) at follow-up. The association between FT4 levels in the first quintile and incident hypertension was also observed in the analysis of combined data from euthyroid individuals and participants with subclinical thyroid dysfunction (RR: 1.04, 95% CI: 1.01-1.07). The associations were predominantly observed with systolic blood pressure levels in euthyroid individuals. However, in the combined analysis incorporating euthyroid participants and individuals with subclinical thyroid dysfunction, the associations were more pronounced with diastolic blood pressure levels. Conclusion: Low FT4 levels may be a mild risk factor for incident hypertension in euthyroid individuals and persons with subclinical thyroid dysfunction.

Factores clínicos y ambientales asociados a la tiroiditis de Hashimoto / Clinical and environmental factors associated with Hashimoto's thyroiditis

Introducción: La tiroiditis de Hashimoto es una enfermedad tiroidea autoinmune poligénica y multifactorial resultante de una interacción compleja de factores genéticos y ambientales. Objetivo: Determinar la posible asociación de los factores clínicos y ambientales con los niveles de anticuerpos antitiroideos y las pruebas de función tiroidea en la tiroiditis de Hashimoto. Métodos: Estudio observacional, descriptivo y transversal con 120 personas con diagnóstico de tiroiditis de Hashimoto. Variables estudiadas: edad, sexo, color de la piel, estado nutricional, paridad, hábito de fumar, consumo de alcohol, preparados estrogénicos, antecedentes familiares de enfermedad autoinmune tiroidea y personales de otras enfermedades autoinmunes. Se realizaron determinaciones de anticuerpos AbTPO, TSH, T3 y T4. Resultados: Predominio del sexo femenino (92,5 por ciento), de pacientes de piel blanca (50,8 por ciento) y con sobrepeso corporal (40 por ciento). El 73 por ciento no consumían preparados estrogénicos. El 20 por ciento tenían antecedentes familiares de enfermedad tiroidea y personales de diabetes mellitus tipo 1 (7,5 por ciento). La media del anticuerpo en pacientes con antecedentes de infecciones virales fue superior a los que no tuvieron este antecedente (732,6 vs. 624,6). El resto de las variables no mostraron diferencias entre las medias del anticuerpo. Ninguno de los factores estudiados mostró asociación con el estado de la función tiroidea. (p>0,05). Conclusiones: No existió asociación entre los factores clínicos y ambientales en relación a los niveles de Ac TPO y el estado de la función tiroidea, con predominio del hipotiroidismo manifiesto al diagnóstico de la TH(AU)

Introduction: Hashimoto's thyroiditis is a polygenic and multifactorial autoimmune thyroid disease, resulting from a complex interaction of genetic and environmental factors. Objective: To determine the possible association of clinical and environmental factors with antithyroid antibody levels and thyroid function tests in HT. Methods: An observational, descriptive, cross-sectional study was carried out with 120 subjects diagnosed with Hashimoto's thyroiditis. We studied variables such as age, sex, skin color, nutritional status, parity, smoking, alcohol consumption, estrogen preparations, family history of autoimmune thyroid disease and personal history of other autoimmune diseases. Additionally, AbTPO, TSH, T3 and T4 antibody determinations were made. Results: Predominance of the female sex (92.5 percent), white skin (50.8 percent) and body overweight (40 percent). 73 percent did not consume estrogenic preparations. Twenty percent had family history of thyroid disease and personal history of type 1 diabetes mellitus (7.5 percent). The mean antibody in patients with history of viral infections was higher than those without this history (732.6 vs. 624.6). The rest of the variables did not show differences between the means of the antibody. None of the factors studied showed association with the state of thyroid function. (p > 0.05). Conclusions: There was no association between clinical and environmental factors in relation to Ac TPO levels and the state of thyroid function, with a predominance of overt hypothyroidism at diagnosis of HT(AU)

Incidence of TPOAb over a 4-year follow-up period: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

ABSTRACT Objective: Although some previous data have suggested a high iodine intake in Brazil, the prevalence of antithyroperoxidase antibodies (TPOAb) in the country is compatible with rates from countries with adequate iodine intake. This observation emphasizes the importance of knowing the incidence of TPOAb in Brazil. Materials and methods: This prospective analysis included euthyroid participants with negative TPOAb at baseline and a thyroid function assessment at a 4-year follow-up. TPOAb was measured by electrochemiluminescence and considered positive when titers were ≥34 IU/mL. TSH and free T4 (FT4) levels were determined by a third-generation immunoenzymatic assay. The incidence of TPOAb is expressed in percentage per year or as a cumulative incidence within the 4-year follow-up period. Results: Of 8,922 euthyroid participants (mean age 51.1 years; 50.9% women) with a negative TPOAb test at baseline, 130 presented incident TPOAb at the 4-year follow-up, yielding an annual incidence of TPOAb of 0.38%/year (95% confidence interval [95% CI], 0.37-0.39%/year) and a cumulative incidence over 4 years of 1.46% (95% CI, 1.21-1.71%). In men, the annual incidence was 0.32% (95% CI, 0.31-0.33%), and the cumulative incidence over 4 years was 1.23% (95% CI, 0.90-1.56%). In women, the annual incidence was 0.43%/year (95% CI, 0.42-0.44%/year) and the cumulative incidence over 4 years was 1.67% (95% CI, 1.30-2.04%). The only factor associated with incident TPOAb was the occurrence of thyroid diseases at follow-up. No differences in TPOAb incidence were detected across ELSA-Brasil research centers. Conclusion: Based on the results of this study, the incidence of TPOAb per year and at a 4-year follow-up period are compatible with those of a country with adequate iodine intake.

Perinatal effects of maternal FT3/FT4 ratio on gestational transient thyrotoxicosis

ABSTRACT Objective: The effects of maternal thyroid hormone levels on the course of pregnancy and birth weight have attracted interest. The aim of the present study was to consider FT3 and FT3/FT4 ratio in the evaluation of the effects of maternal thyroid functions in gestational transient thyrotoxicosis (GTT). Materials and methods: This case-control study included 45 patients with GTT and 45 healthy pregnant women. Maternal history before pregnancy, thyroid function tests, thyroid autoantibodies, and thyroid ultrasonography results in 6th to 10th weeks of pregnancy were used in the differential diagnosis of GTT. In both groups, the effects of FT3, FT4 and FT3/FT4 ratios on gestational age and birth weight were evaluated. Results: There was no significant difference in the gestational age between the GTT and control groups (39,3±1,0 weeks and 39,2±1,2 weeks, respectively). Birth weights were similar in both groups (3205,2±4899 g and 3196,6±309,3 g, respectively). When maternal weight was adjusted, a positive correlation was observed between maternal FT3/FT4 ratio and birth weight (r=0,317, p=0,017). Additionally there was a positive correlation between the gestational age and the birth weight in the control group (ρ=0,726, p=0,001). Conclusion: GTT had no significant effect on the gestational age and the birth weight. On the other hand an increase in the maternal FT3/FT4 ratio had a positive effect on the birth weight in the patient with GTT. Maternal characteristics (age, weight, BMI) and FT3/FT4 ratio should be taken into consideration in future impact assessment studies on this issue.

Reproductive outcomes in cases of subclinical hypothyroidism and thyroid autoimmunity: a narrative review / Resultados reprodutivos nos casos de hipotireoidismo subclínico e autoimunidade tireoidiana: Uma revisão narrativa

Abstract Thyroid diseases are relatively common in women in the reproductive period. It is currently understood that clinically-evident thyroid disorders may impair ovulation and, consequently, fertility. However, to date it has not been proven that high serum levels of thyroid-stimulating hormone and/or positivity for antithyroid antibodies are associated to a reduction in fertility, mainly in the absence of altered thyroxine levels. The present comprehensive review aims to present current data on the association between subclinical hypothyroidism and/or thyroid autoimmunity and reproductive outcomes.

Resumo As doenças da tireoide são relativamente comuns em mulheres no período reprodutivo. Atualmente, entende-se que distúrbios da tireoide clinicamente evidentes podem prejudicar a ovulação e, consequentemente, a fertilidade. No entanto, não se provou até o presente que níveis séricos altos do hormônio estimulador da tireoide e/ou positividade para anticorpos antitireoidianos estão associados a uma redução na fertilidade, sobretudo na ausência de níveis alterados de tiroxina. Esta revisão narrativa tem como objetivo apresentar dados atuais sobre a associação entre hipotireoidismo subclínico e/ou autoimunidade tireoidiana e resultados reprodutivos.

TRH stimulation test in patients with repeatedly elevated TSH and normal FT4 / Teste de estímulo com TRH em pacientes com TSH repetidamente elevado e T4L normal

ABSTRACT Subclinical hypothyroidism (SCH) is defined by elevated thyroid-stimulating hormone (TSH) with normal free thyroxine (FT4). We aimed to evaluate the thyrotropin-releasing hormone (TRH) stimulation test in patients with repeatedly elevated TSH (up to 10 mIU/l) and normal FT4, but without apparent thyroid disease. Women with TSH > 4.5 and ≤ 10 mIU/l (in two measurements) and normal FT4 were selected. Women with a known non-thyroid cause of TSH elevation, those treated with anti-thyroid drugs, amiodarone, lithium, and those with a history of thyroidectomy, neck radiotherapy and 131I treatment were excluded. Seventy women had negative antithyroperoxidase antibodies. Ultrasonography revealed a eutopic thyroid, usual echogenicity, and a volume ≤ 15 ml, and they underwent the TRH stimulation test during initial evaluation. After stimulation with TRH, TSH > 30 mIU/l was observed in 38 women (expected response), while 32 women had TSH < 20 mIU/l (inadequate response). Age, basal TSH or thyroid volume did not differ between both groups, but FT4 concentrations were significantly lower in the first group. Follow-up was available for 66/70 women. Seven women developed a need for levothyroxine, all of them in the group with an adequate response to TRH [7/36 (19.4%) versus 0/30]. The results suggest that some cases of TSH elevation (even persistent) do not represent the early stage of thyroid insufficiency.

RESUMEN El hipotiroidismo subclínico (HSC) es definido por la elevación de los niveles de hormona tiroestimulante (TSH) con los niveles de tiroxina libre (T4L) dentro de rangos de normalidad. El objetivo de este reporte fue evaluar la prueba de estímulo con hormona liberadora de tirotropina (TRH) en pacientes con TSH persistentemente elevado (hasta 10 mUI/l) y T4L normal, pero sin enfermedad tiroidea aparente. Se eligieron mujeres con TSH > 4,5 y ≤ 10 mUI/l (en dos medidas) y T4L normal. Se excluyeron aquellas con causa no tiroidea conocida de alza de TSH además de las tratadas con medicamentos antitiroideos, amiodarona, litio y con historia de tiroidectomía, radioterapia cervical y tratamiento con 131I. Setenta mujeres presentaron anticuerpos antitiroperoxidasa negativos. La ecografía mostró tiroides eutópica, ecogenicidad usual y volumen ≤ 15 ml; todas se sometieron a la prueba de estímulo con TRH en la evaluación inicial. Tras estímulo con TRH, TSH > 30 mUI/l se observó en 38 mujeres (respuesta esperada), mientras 32 mujeres presentaron TSH < 20 mUI/l (respuesta inadecuada). El seguimiento estuvo disponible para 66/70 mujeres. Siete pacientes evolucionaron con necesidad de levotiroxina, todas ellas en el grupo con respuesta adecuada al TRH [7/36 (19,4%) versus 0/30]. Los resultados sugieren que algunos casos de alza de TSH (aunque persistente) no representan la fase inicial de una insuficiencia tiroidea.

RESUMO O hipotireoidismo subclínico (HSC) é definido pela elevação dos níveis de hormônio tireoestimulante (TSH) com os níveis de tiroxina livre dentro da normalidade (T4L). O objetivo deste relato foi avaliar o teste de estímulo com hormônio liberador de tirotrofina (TRH) em pacientes com TSH repetidamente elevado (até 10 mUI/l) e T4L normal, mas sem doença tireoidiana aparente. Mulheres com TSH > 4,5 e ≤ 10 mUI/l (em duas medidas) e T4L normal foram selecionadas. Foram excluídas aquelas com causa não tireoidiana conhecida de elevação do TSH, além das tratadas com medicamentos antitireoidianos, amiodarona, lítio e com histórico de tireoidectomia, radioterapia cervical e tratamento com 131I. Setenta mulheres apresentaram anticorpos antitireoperoxidase negativos. A ultrassonografia revelou tireoide eutópica, ecogenicidade usual e volume ≤ 15 ml; todas foram submetidas ao teste de estímulo com TRH na avaliação inicial. Após estímulo com TRH, TSH > 30 mUI/l foi observado em 38 mulheres (resposta esperada), enquanto 32 mulheres apresentaram TSH < 20 mUI/l (resposta inadequada). Idade, TSH basal ou volume da tireoide não diferiram entre os dois grupos, mas as concentrações de T4L foram significativamente menores no primeiro grupo. O acompanhamento foi disponível para 66/70 mulheres. Sete pacientes evoluíram com necessidade de levotiroxina, todas elas no grupo com resposta adequada ao TRH [7/36 (19,4%) versus 0/30]. Os resultados sugerem que alguns casos de elevação do TSH (mesmo persistente) não representam a fase inicial de uma insuficiência tireoidiana.

Interpretación de las pruebas de función tiroidea / Interpretation of thyroid function tests

Los desórdenes de la glándula tiroides son comunes y pueden afectar hasta el 10% de la población en general. En muchas ocasiones los síntomas pueden ser inespecíficos, por lo que el médico en busca de un trastorno tiroideo debe llegar a un diagnóstico funcional y anatómico. Las mediciones séricas de las hormonas tiroideas confirman si hay un exceso, un déficit o si las concentraciones son normales. Para ello, se requiere un rango de referencia de la población local, y específicamente por grupos de edad, para una correcta interpretación de las pruebas de función tiroidea. Las hormonas tiroideas juegan un papel fundamental en el sistema endocrino, controlan el metabolismo general del cuerpo, el desarrollo neural, el crecimiento normal y la maduración de los huesos, así como funciones cardiovasculares y renales, entre otras. En esta revisión se pretende dar una aproximación a las pruebas tiroideas más relevantes, partiendo de la biosíntesis y secreción de las hormonas tiroideas, hasta llegar al abordaje para un diagnóstico inicial del paciente con trastorno tiroideo, mencionando los aspectos más importantes de los diferentes patrones tiroideos. El tratamiento detallado de cada uno de ellos, supera las expectativas de esta revisión

Thyroid gland disorders are common and can affect up to 10% of the general population. In many cases the symptoms can be nonspecific, so the physician in search for a thyroid disorder should reach a functional and anatomical diagnosis. Serum measurements of thyroid hormones confirm if there is an excess, a deficit, or if concentrations are normal. For this, reference ranges of the local population, and specifically by age groups, are required for a correct interpretation of thyroid function tests. Thyroid hormones play a fundamental role in the endocrine system, control of the general metabolism of the body, neural development, normal growth and maturation of bones, as well as in cardiovascular and renal functions, among others. In this review, the most relevant thyroid tests will be described, starting with the biosynthesis and secretion of thyroid hormones, and continuing with an approach to reach an initial diagnosis. Finally, the most important aspects of the different thyroid patterns will be mentioned. It is beyond the scope of this review, to describe the treatment for thyroid disorders.

Evaluation of Prevalence of Changes in Thyroid Functional Tests in Mole Hydatiforme

Introduction: Mole hydatiforme is the most common type of gestational trophoblast disease (GTI) and the aim of this study, is evaluation the frequency of changes in thyroid function test in mole hydatidiform patients. Materials and Methods: In this retrospective study, 63 patients with mole hydatidiform who reffering to gynecolgy ward of Ali ibn Abitaleb Hospital in Zahedan from April 2016 to March 2017, were studied. Information such as age, gravidity and laboratory findings inclluding thyroid function test (TFT) and the presence or absence of clinical sympltoms were recorded in the information forms and analyzed by SPSS software. Results: In this study, 63 patients with mole hydatidiform were studied. The mean age of the patients was 26.6 ± 7.7 years. The most common clinical manifestations of hyperthyroidism in patients with mole hydatidorme was tachycardia (39.7%). There was no relationschip between age and gravidity with the hyperthyroid simptoms and thyroid function test. Conclusion: Overall, the results of this study showed ttat 67% of patients with mole hydatidiform hay reduced TSH and more than 50% of cases hay increased free T3 and T4. There was no relationship between maternal age and gravidity with changes in thyroid functional test (AU)

Thyroid function in pediatric population with different nutritional status / Función tiroidea en población pediátrica con diferente estado nutricional

Abstract: Background: Thyroid dysfunction has been associated with the development of obesity. There are few studies describing their status in Mexican schoolchildren, in whom obesity and subclinical hypothyroidism (SCH) prevail. Methods: Levels of stimulating thyroid hormone (TSH) and thyroid hormones (TH) were correlated with anthropometric variables as indicators of nutritional status in schoolchildren residents of Mexico City. The thyroid status and prevalences of SCH were compared between all the nutritional conditions, considering the degree of pubertal development. Results: The mean of TSH was 2.96 ± 1.48 mIU/L, and the prevalence of SCH was 11.30%. TSH levels are higher in prepubertal (5.21 ±1.24 mIU/L (95% confidence interval [CI]: 3.72-6.69) versus pubertal children (2.96 ± 1.48 mIU/L [95% CI: 2.61-3.30), as well as in children with obesity (3.5 ± 1.13 mIU/L [95% CI: 2.98-4.02]) versus normal weight children (2.43 ± 1.37 mIU/L [95% CI: 1.88 - 2.97]). The TH is similar in the whole population, although triiodothyronine total levels tend to be lower in malnourished children. There is a positive correlation between TSH levels and all anthropometric variables. The prevalences of SCH were higher in groups of children with overweight and obesity. Conclusions: The body fat content is associated with thyroid status in Mexican schoolchildren. In addition, it is relevant to consider the degree of pubertal development for diagnosing hyperthyrotropinemia in children and adolescents.

Resumen: Introducción: La disfunción tiroidea se ha asociado con el desarrollo de obesidad. Existen pocos estudios descritos en población escolar mexicana, en quienes prevalece la obesidad y el hipotiroidismo subclínico (HSC). Métodos: Los niveles de hormona estimulante de tiroides (TSH) y hormonas tiroideas (HT) se correlacionaron con variables antropométricas indicadoras del estado nutricional de niños escolares residentes de la Ciudad de México. El estado tiroideo y las prevalencias de HSC se compararon entre todas las condiciones nutricionales, considerando el grado de desarrollo puberal. Resultados: La media de TSH fue 2.96 ± 1.48 mUI/L, y la prevalencia de HSC fue de 11.30%. Los niveles de TSH fueron mayores en los niños prepúberes (5.21 ± 1.24 mUI/L [intervalo de confianza (IC) 95%: 3.72-6.69]) vs. los niños púberes (2.96 ± 1.48 mUI/L [IC 95%: 2.61-3.30); así como en los niños con obesidad (3.50 ± 1.13 mUI/L [IC 95%: 2.98-4.02]) vs. los niños con peso normal (2.43 ± 1.37 mUI/L [IC 95%: 1.88-2.97]). Los niveles de HT son similares en toda la población, aunque los niveles de triiodothyronine total (T3) tienden a ser menores en niños desnutridos. Existe correlación positiva entre los niveles de TSH y todas las variables antropométricas. Las prevalencias de HSC fueron mayores en los grupos de niños con sobrepeso y obesidad. Conclusiones: El contenido de grasa corporal está asociado con el estado tiroideo en escolares mexicanos. Adicionalmente, es relevante considerar el grado de desarrollo puberal para el diagnóstico adecuado de hipertirotropinemia en niños y adolescentes.

Discrepancia en concentraciones de hormonas tiroideas libres medidas por distintos inmunoensayos / Discrepancy in concentrations of free thyroid hormones measured by different immunoassays

Abstract: Thyroid function is assessed by measuring thyrotropin and free and total thyroid hormone concentrations. There are interferences with the results of immunoassays that can lead to an incorrect diagnosis, of which the most frequent are the binding of thyroid hormones to heterophile antibodies, rheumatoid factor, anti-Ruthenium antibodies, the intake of biotin and anti-streptavidin antibodies. We present three cases of clinically euthyroid patients, with normal TSH, high free T4 and T3, and normal total T4 and T3 performed in a Roche Diagnostics ® COBAS 8000 device. When the test was repeated on a Siemens® Immulite device, the free and total hormones were within normal ranges. In the Roche Diagnostics ® assay, the presence of biotin or anti-Ruthenium or anti-streptavidin antibodies interferes with the formation of the complex responsible for the emission of light that allows inferring concentrations of thyroid hormones. The Siemens test works differently since the emission of light depends on the binding of T4 to an antibody conjugated with alkaline phosphatase not participating in the process biotin, streptavidin or ruthenium so this interference is avoided. This possible interference in immunoassays should be taken into account in case clinical manifestations differ from these laboratory determinations, to avoid a diagnosis and potential inappropriate treatment.

Resumen: La función tiroidea se evalúa midiendo tirotropina y concentraciones de hormonas tiroideas libres y totales. Existen interferencias con los resultados de inmunoensayos que pueden llevar a un diagnóstico incorrecto, de ellas, las más frecuentes son la unión de hormonas tiroideas a anticuerpos heterófilos, el factor reumatoide, anticuerpos anti Rutenio, la ingesta de biotina y anticuerpos anti estreptavidina. Se presentan tres casos de pacientes clínicamente eutiroideos, con TSH normal, T4 y T3 libres elevadas, y T4 y T3 totales normales realizadas en un equipo COBAS 8000 de Roche Diagnostics®. Cuando se repitió el ensayo en un equipo Immulite de Siemens®, las hormonas libres y totales estaban dentro de rangos normales. En el ensayo de Roche Diagnostics ®, la presencia de biotina o anticuerpos anti Rutenio o anti estreptavidina, interfiere con la formación del complejo responsable de la emisión de luz que permite inferir las concentraciones de las hormonas tiroideas. El ensayo de Siemens funciona de manera diferente ya que la emisión de luz depende de la unión de la T4 a un anticuerpo conjugado con fosfatasa alcalina no participando en el proceso biotina, estreptavidina o Rutenio por lo que se evita esta interferencia. Esta posible interferencia en inmunoensayos debe ser tenida en cuenta en caso de que las manifestaciones clínicas difieran de estas determinaciones de laboratorio, para evitar un diagnóstico y potencial tratamiento inadecuado.

Patología tiroidea en el síndrome de ovario poliquístico

Objetivo: Determinar la función y ecoestructura tiroidea en pacientes con síndrome de ovario poliquístico, así como la asociación con la resistencia a la insulina. Métodos: Se determinó función y ecoestructura tiroidea en 64 pacientes con diagnóstico reciente de síndrome de ovario poliquístico, sin tratamiento, divididas en dos grupos de 32 pacientes cada uno según la presencia de resistencia a la insulina, el grupo 1(G1) con HOMA-IR >2,5 y grupo 2 (G2)con HOMA-IR<2,5. Resultados: Se observó en la función tiroidea, en el G1, 15/32 (46,9 %) pacientes con TSH>2,5 μUI/mL. Para el G2 7/32 (21,9 %) pacientes con TSH>2,5 μUI/mL, (P=0,035). La presencia de AntiTPO positivos se identificó en 11/32 (34,4 %) pacientes del G1 y 6/32 (18,8 %) del G2 (P=0,15), con un total de 53,2 % de enfermedad tiroidea autoinmune identificada de manera independiente a la presencia de resistencia a la insulina. La evaluación ecográfica de la glándula tiroides, reveló la presencia de nódulos en 12/32 (37,6 %) de las pacientes del G1, y 4/32 (12,5 %) del G2 (P= 0,025). Se observó sobrepeso y obesidad en 74,99 % de las pacientes del G1 y 37,49 % del G2 (P= 0,001). Otros parámetros fueron evaluados, como el hirsutismo, el cual se identificó en 96,9 % pacientes del G1, y 62,5 % en el G2 (P=0,002). El índice de andrógenos libres (IAL) fue >3,8 en 20/32 (62,5 %) pacientes del G1 y 14/32 (43,8 %) en el G2 (P=0,13). Conclusiones: La prevalencia de enfermedad tiroidea autoinmune en síndrome de ovario poliquístico es mayor a la identificada en la población general, las bases moleculares se direccionan a un gen común, sin embargo, esto aun no ha sido bien aclarado. Los efectos de la resistencia a la insulina en síndrome de ovario poliquístico no se limitan a la función ovárica, su relación con valores elevados de TSH y cambios ecográficos de la glándula tiroides, en especial para la presencia de patología nodular, justifica su evaluación para un correcto abordaje terapéutico.

Objective: The purpose of this study was to determine thyroid function and echostructure in policystic ovary syndrome, as well as the association of these with insulin resistance. Methods: Echostructure and thyroid function were determined in 64 patients newly diagnosed with policystic ovary syndrome, without treatment, divided into two groups of 32 patients each according to the presence of insulin resistance, group 1 (G1) with HOMA-IR> 2.5 and Group 2 (G2) with HOMA-IR <2.5. Results: The thyroid function in the G1 was, 15/32 (46.9 %) patients with TSH> 2.5 mUI / mL. For G2 7/32 (21.9 %) patients with TSH> 2.5 mUI / mL (P = 0.035). The presence of positive AntiTPO identified in 11/32 (34.4 %) patients in G1 and 6/32 (18.8 %) of G2 (P = 0.15), a total of 53.2 % of Autoimmune Thyroid Disease (ATD) independently of the presence of insulin resistance. Ultrasound evaluation of the thyroid gland, revealed the presence of nodules in 12/32 (37.6 %) of G1, and 4/32 (12.5 %) of G2 (P = 0.025). Overweight and obesity was observed in 74.99 % of patients in the G1 and G2 37.49 % (P = 0.001). Other parameters were assessed, as hirsutism, which was identified in 96.9 % of patients in G1 and G2 62.5 % (P = 0.002). The free androgen index was> 3.8 in 20/32 (62.5 %) patients in G1 and 14/32 (43.8 %) in G2 (P = 0.13). Conclusions: The prevalence of Autoimmune Thyroid Disease in policystic ovary syndrome is higher than in the general population, the molecular basis point to a common gene, however this has not yet been well clarified. The effects of insulin resistance in policystic ovary syndrome are not limited to ovarian function, its relationship with elevated TSH and ultrasound changes of the thyroid gland, especially for the presence of nodular pathology justifies its evaluation for correct therapeutic approach.

Hipotiroidismo y apnea del sueño / Hypothyroidism and sleep apnea

Resumen La salud es un derecho fundamental de todo ser humano, ya reconocido por la Ley Estatutaria de Salud (Ley 1751 de 2015). Esta ley devuelve la autonomía profesional al médico y para hacer buen uso de ella, debemos ejercer nuestra profesión dentro de un marco de autorregulación, ética, racionalidad y evidencia científica. Somos los médicos los llamados a liderar la identificación de los gastos innecesarios en salud, sin descuidar la calidad de la atención. Iniciamos aquí una serie de artículos en los que esperamos exponer, bajo evidencia científica, cuáles prácticas en medicina debemos continuar, mejorar o abolir con el fin de autorregularnos bajo conceptos éticos, de calidad y de racionalidad científica. El cuadro clínico del hipotiroidismo y de la apnea del sueño son bastantes similares, sin embargo cada una tiene unas características clínicas particulares que son las que debemos evaluar. ¿Se recomienda solicitar rutinariamente pruebas de función tiroidea a todos los pacientes con sospecha diagnóstica o diagnóstico confirmado de apnea del sueño?; ¿Se recomienda realizar un estudio del sueño a todos los pacientes con diagnóstico de hipotiroidismo clínico o subclínico?. No se recomienda realizar pruebas de función tiroidea a todos los pacientes con diagnóstico de apnea del sueño, así como tampoco hacer estudio del sueño a todos los pacientes con hipotiroidis-mo. Solo se recomienda hacer cuando la sospecha clínica lo amerite. Sugerimos la realización de investigaciones de costo/efectividad. (Acta Med Colomb 2016; 41: 138-140).

Abstract Health is a fundamental right of every human being, as recognized by the Statutory Health Law (Law 1751 of 2015). This law puts professional autonomy to the doctor, and to make good use of it we must exercise our profession within a framework of self-regulation, ethics, rationality and scientific evidence. We the physicians are the ones who are called to lead the identification of unnecessary health expenses without sacrificing quality of care. We begin here a series of articles in which we expect expose, on scientific evidence, which medical practices must we continue, improve or abolish in order to self-regulate us under ethical, quality and scientific rationality concepts. The clinical picture of hypothyroidism and sleep apnea are quite similar, yet each has unique clinical features that are what we have to assess. Is it recommended routinely request thyroid tests to all patients with suspected or confirmed diagnosis of sleep apnea?. Is it recommended to perform a sleep study to all patients diagnosed with clinical or subclinical hypothyroidism?. It is not recommended practice thyroid function tests to all patients diagnosed with sleep apnea, nor do sleep study to all patients with hypothyroidism. It is recommended only when the clinical suspicion warrants it. We suggest carry out cost / effectiveness research. (Acta Med Colomb 2016; 41: 138-140).

The prevalence of the metabolic syndrome increases through the quartiles of thyroid stimulating hormone in a population-based sample of euthyroid subjects / Prevalência de síndrome metabólica aumenta em quartis de hormônio tireoestimulante em uma amostra de sujeitos eutiroides baseada na população

Objective The aim of the study was to assess the prevalence and characteristics of metabolic syndrome (MetS) and its elements in relation to TSH in euthyroid subjects. Materials and methods In the cross-sectional study, 2,153 euthyroid adults, 47.2 ± 14.5 years (20-94) with no current antithyroid or thyroid replacement therapy were enrolled. All participants filled a questionnaire on past and current morbidities, medication and smoking. Body weight, height, waist circumference, serum TSH, glucose and lipids were measured. The subjects were stratified by quartiles of TSH (QTSH) and the prevalence of the MetS elements was calculated. MetS was determined by the IDF 2005 criteria. Results Overweight prevalence was 37.2% (35.2-39.2), obesity in 25.1% (23.3-26.9), abdominal obesity – 61.4% (59.3-63.5), hypertension – 42.1% (38.9-43.1), diabetes/increased fasting glucose – 13.6% (12.1-15), low HDL-cholesterol – 27.6% (25.7-29.5), hypertriglyceridemia – 24.1% (22.3-25.9), MetS – 32.2% (30.2-34.2). MetS was more prevalent in the highest QTSH (34.9%, 30.9-38.9) than the lowest (27%, 23.3-30.9), p < 0.001, as were low HDL-C (32%, 28-35.9 vs. 25%, 21.3-28.7, p < 0.001) and hypertriglyceridemia (26.8%, 23-30.5 vs. 20.4%, 17-23.8, p = 0.015). Each QTSH increased the risk of MetS by 14%, p < 0.001, of hypertriglyceridemia by 20%, p = 0.001 and of low LDL-C by 9%, p = 0.042. Other significant factors for MetS were age, male gender and obesity. Conclusion The prevalence of MetS increased with higher QTSH within the euthyroid range, mostly by an increase in the dyslipidemia. Arq ...

Objetivo O objetivo deste estudo foi avaliar a prevalência e características da síndrome metabólica (MetS) e seus elementos em relação ao TSH em sujeitos eutireoides. Materiais e métodos Foram analisados, em um estudo transversal, 2.153 adultos eutiroides, de 47,2 ± 14,5 anos (20-94) sem terapia antitiroidiana ou de reposição. Todos os participantes preencheram um questionário sobre doenças atuais e passadas, medicações e tabagismo. O peso corporal, altura, circunferência da cintura, TSH, glicose e lipídios séricos foram medidos. Os sujeitos foram estratificados em quartis de TSH (QTSH) e a prevalência dos elementos da MetS foram calculados. Os critérios da MetS foram determinados pela IDF 2005. Resultados A prevalência de sobrepeso foi de 37,2% (35,2-39,2), de obesidade – 25,1% (23,3-26,9), obesidade abdominal – 61,4% (59,3-63,5), hipertensão – 42,1% (38,9-43,1), diabetes/aumento da glicose de jejum – 13,6% (12,1-15), baixo colesterol HDL – 27,6% (25,7-29,5), hipertrigliceridemia – 24,1% (22,3-25,9), MetS – 32,2% (30,2-34,2). A MetS foi mais prevalente no QTSH mais alto (34,9%; 30,9-38,9) do que no mais baixo (27%; 23,3-30,9), p < 0,001, assim como o baixo HDL-C (32%, 28-35,9 contra 25%, 21,3-28,7; p < 0,001) e hipertrigliceridemia (26,8%; 23-30,5 contra 20,4%, 17-23,8; p = 0,015). Cada QTSH aumentou o risco MetS em 14%, p < 0,001, de hipertrigliceridemia em 20%, p = 0,001 e de baixo LDL-C em 9%, p = 0,042. Outros fatores significativos para a MetS foram idade, sexo masculino e obesidade. ...

Rol del eje tirotrópico en enfermedades neurodegenerativas / Thyrotropic Axis Role in Neurodegenerative Disorders

Las hormonas tiroideas actúan como reguladores primarios del metabolismo intermediario en todos los tejidos del organismo; tienen funciones de gran trascendencia a nivel del sistema nervioso, donde ejercen acciones potencialmente neuroprotectoras. Los niveles de las hormonas tiroideas están sujetos a una estrecha regulación en el sistema nervioso y se sugiere que incluso ligeras desviaciones del rango de normalidad pueden estar asociadas a enfermedades neurodegenerativas. En esta revisión se resumieron los hallazgos existentes en torno al papel de las hormonas tiroideas en la fisiología normal y patológica del sistema nervioso, con énfasis en enfermedades neurodegenerativas y los mecanismos moleculares implicados. Las evidencias indican un rol significativo para las hormonas tiroideas en varias enfermedades neurodegenerativas, si bien es necesaria la realización de estudios prospectivos de mayor envergadura para precisar su función y evaluar su utilidad como bio-marcadores y dianas terapéuticas.

Thyroid hormones are primary regulators of intermediate metabolism in all body tissues. Particularly, they have very important functions at the level of nervous system, even having potentially neuro-protective effects. Usually, thyroid hormone levels are under a very close regulation in the nervous system and, because of that, small deviations from the normality range can be associated to neurodegenerative conditions. In this review, evidences about the roles of thyroid hormones in normal and pathological physiology of the nervous system are summarized, with an emphasis in neurodegenerative disorders and the molecular mechanisms involved. Findings suggest a significant role for thyroid hormones in several neurodegenerative diseases, although larger prospective studies are needed to clarify their function and to assess their usefulness as biomarkers and therapeutic targets.

Utilização dos testes de função tireoidiana na prática clínica / The clinical use of thyroid function tests

Exames laboratoriais são fundamentais para o diagnóstico acurado e o monitoramento custo-efetivo das disfunções tireoidianas. Quando há alta suspeita clínica, as dosagens hormonais apenas confirmam o diagnóstico. No entanto, na maioria dos pacientes, a sintomatologia é sutil e inespecífica, de forma que apenas testes bioquímicos podem detectar o transtorno. O objetivo deste artigo é fazer uma análise crítica do uso apropriado dos principais testes de função tireoidiana, entre eles a dosagem sérica do hormônio estimulante da tireoide (TSH), dos hormônios tireoidianos e dos anticorpos antitireoidianos. Mediante um levantamento na base de dados do MedLine, são discutidas as principais armadilhas e interferências relacionadas ao uso cotidiano desses testes e apresentadas recomendações para otimizar a utilização dessas ferramentas diagnósticas na prática clínica.

Laboratory tests are essential for accurate diagnosis and cost-effective management of thyroid disorders. When the clinical suspicion is strong, hormonal levels just confirms the diagnosis. However, in most patients, symptoms are subtle and unspecific, so that only biochemical tests can detect the disorder. The objective of this article is to do a critical analysis of the appropriate use of the most important thyroid function tests, including serum concentrations of thyrotropin (TSH), thyroid hormones and antithyroid antibodies. Through a survey in the MedLine database, we discuss the major pitfalls and interferences related to daily use of these tests and recommendations are presented to optimize the use of these diagnostic tools in clinical practice.

Clinical evaluation with self-sequential longitudinal reference intervals: pregnancy outcome and neonatal thyroid stimulating hormone level associated with maternal thyroid diseases / Evaluación clínica con intervalos de referencia longitudinal auto-secuencial: evolución clínica del embarazo y niveles de la hormona estimulante de la tiroides en neonatos asociados con enfermedades tiroideas maternas

OBJECTIVE: We attempted to evaluate maternal thyroid function in a new self-sequential longitudinal reference interval (SLRI) which we established recently. By this method, we analysed the correlation between pregnancy outcome, neonatal thyroid stimulating hormone (TSH) level and maternal thyroid diseases. METHODS: A total of 1744 pregnant women participated in the study and 1747 babies were born from those women (three bore twins). The levels of TSH, free thyroxine (FT4) and thyroid peroxidase antibodies (TPO-Ab) of mothers were quantified by electrochemistry immunoassay (ECL). The levels of neonatal blood TSH were detected by time-resolved fluorescence immunoassay (TRFIA). All data were collected and statistically analysed by SPSS 13.0 software. RESULTS: With our new SLRI method, we found that 0.11%~3.84% pregnant women would get thyroid diseases. Subclinical hypothyroidism was the most common maternal thyroid disorder. Being positive for thyroid peroxidase antibodies was a significant risk factor of subclinical hypothyroidism during pregnancy. The median, P2.5~P97.5, and interquartile range (IQR) of neonatal TSH (N-TSH) of 1747 babies were 2.72 mIU/L, 0.10~8.01 mIU/L and 2.62 mIU/L, respectively; 28.6% of pregnant women with thyroid diseases developed pregnancy complications. The prevalence was significantly higher than in the normal thyroid function group (p< 0.001). The levels of N-TSH were low correlated with maternal TSH levels (p < 0.05), but there were no significant correlations between N-TSH and maternal FT4 and maternal TPO-Ab (p > 0.05). CONCLUSIONS: Thyroid disorders, especially subclinical hypothyroidism, are common in pregnant women. These disorders are associated with pregnancy and fetal outcome. Routine maternal thyroid function screening is important and should be recommended.

OBJETIVO: Intentamos evaluar la función tiroidea materna en un nuevo intervalo de referencia longitudinal auto-secuencial (SLRI) que establecimos recientemente. Por este método, analizamos la correlación entre el resultado del embarazo, el nivel de la hormona estimulante de la tiroides (TSH) en neonatos, y las enfermedades tiroideas maternas MÉTODOS: Un total de 1744 mujeres embarazadas participó en el estudio y 1747 bebés nacieron de esas mujeres (tres de ellas tuvieron gemelos). Los niveles de TSH, la tiroxina libre (FT4), y los anticuerpos de la peroxidasa tiroidea (TPO-Ab) de las madres, fueron cuantificados mediante inmunoensayo electroquímico (ECL). Los niveles de TSH en la sangre de los neonatos, fueron determinados mediante inmunoensayo por fluorescencia resuelto en el tiempo (TRFIA). Todos los datos fueron recogidos y analizados estadísticamente usando el software SPSS 13.0 RESULTADOS: Con nuestro nuevo método SLRI, encontramos que 0.11%~3.84% de las mujeres embarazadas contraerán enfermedades tiroideas. El hipotiroidismo subclínico fue el trastorno de la tiroides materna más común. Ser positivo a los anticuerpos de la peroxidasa tiroidea fue un factor de riesgo significativo del hipotiroidismo subclínico durante el embarazo. La mediana, P2.5~P97.5, y el rango intercuartil (IQR) de la TSH (N-TSH) neonatal de los 1747 bebés fueron 2.72 mIU/L, 0.10~8.01 mIU/L y 2.62 mIU/L respectivamente. El 28.6% de las mujeres embarazadas que tenían enfermedades tiroideas, desarrollaron complicaciones del embarazo. La prevalencia fue significativamente más alta que en el grupo con función tiroidea normal (p < 0.001). Los niveles de N-TSH fueron bajos en correlación con los niveles de TSH maternos (p < 0.05), pero no hubo ninguna correlación significativa entre la N-TSH y la FT4 materna, y la TPO-Ab materna (p > 0.05). CONCLUSIÓNS: Los trastornos tiroideos, especialmente el hipotiroidismo, son comunes en las mujeres embarazadas.Estos trastornos se hallan asociados con el resultado del embarazo y el resultado fetal. El tamizaje de rutina de la función tiroidea materna es importante y debe recomendarse.

Insulinorresistencia asociada a cambios en los niveles de tirotrofina en pacientes eutiroideos o con disfunción tiroidea subclínica / Insulin Resistance and Changes in thyrotropin levels in patients with euthyroidism or subclinic thyroid dysfunction

La relación entre síndrome metabólico y disfunción tiroidea subclínica es un tema aun controvertido. Por tal motivo, el objetivo principal de nuestro trabajo fue tratar de establecer la existencia de una asociación entre la insulinorresistencia medida por el HOMA-IR (Homeostasis Model Assessment) con los niveles de TSH en pacientes eutiroideos o con disfunción tiroidea subclínica. A su vez, y en forma secundaria, se valoraron cambios en el perfil lipídico. Se analizaron los niveles de T4L, TSH, insulina, glucemia, colesterol total, HDL colesterol, triglicéridos e índice de masa corporal en 233 pacientes eutiroideos o con disfunción tiroidea subclínica y se dividieron en tres grupos según su nivel de TSH: Grupo A: TSH < de 0,4; Grupo B: TSH entre 0,4 y 2,5 y Grupo C: TSH > de 2,5 mUI/L. Encontramos que, los niveles de insulina y el HOMA-IR en el grupo B fueron significativamente menores que en el grupo C (7,91 ± 0,67 mUI/L vs. 10,23 ± 0,91 mUI/L - p = 0,0073 y 1,84 ± 0,17 vs. 2,49 ± 0,27 - p = 0,0113, respectivamente). Esta diferencia fue independiente de la edad y del IMC. Además, se encontró una leve pero significativa disminución de los niveles de HDL-colesterol en el grupo C respecto al B (48,3 ± 0,5 vs. 46,3± 0,7 mg/dl; p = 0,0455) y un incremento de los triglicéridos (146,9 ± 11,9 vs. 112,3 ± 5,6 mg/dl; p = 0,0162). La prevalencia de insulinorresistencia definida como un valor de HOMA-IR > de 2,5 fue superior en el grupo C comparado con el B (39,5 % vs. 23,9 %; OR de 2,06 - IC 95 %: 1,19-3,63 - p = 0,013). Por último, se observó una débil pero significativa correlación negativa entre HOMA-IR y T4L (r - 0,2336; p = 0,0047) y positiva entre HOMA-IR y TSH (r = 0,1909; p = 0,0066) en toda la cohorte analizada. Concluimos que en la población analizada, los pacientes con TSH > de 2,5 mUI/L presentaron: a) niveles de HDL colesterol más bajos, b) triglicéridos y HOMA-IR más elevados, independientemente de la edad y del IMC, y c) un aumento significativo del riesgo de tener insulinorresistencia medida por HOMA-IR. Los autores declaran no poseer conflictos de interés.

Introduction: The association between alterations of the thyroid function and an increased risk of developing cardiovascular diseases has been established for several years. Strong published evidence supports the notion that clinical hypothyroidism increases the levels of LDL cholesterol, induces arterial hypertension, and increases the levels of homocystein. However, the relationship between all these well-known risk factors for coronary disease and subclinical thyroid dysfunction remains a controversial topic. In addition, the presence of Metabolic Syndrome, known as an association of cardiovascular risk factors including: central obesity, insulin resistance, dyslipidemia and arterial hypertension, increases the possibility of developing cardiovascular diseases, to such an extent that the main cause of death in patients with type 2 diabetes, who generally present all the aforementioned factors plus hyperglycemia, is myocardial infarction. Objective: The main objective of our study was to investigate the existence of an association between insulin resistance measured by HOMA-IR and TSH levels in euthyroid patients or subclinical thyroid dysfunction. Secondarily, we evaluated changes in the lipid profile of the groups studied. Methods: This was a retrospective study. We analyzed the levels of free T4, TSH, insulin, basal plasma glucose, total and HDL cholesterol, triglycerides and body mass index in 233 patients with euthyroidism or diagnosed with subclinical thyroid dysfunction. Patients were divided into three groups according to TSH levels: Group A (n = 31) with values of TSH less than 0.4 mIU/L; Group B (n = 136) with TSH between 0.4 and 2.5 mIU/L, and Group C (n = 66) with TSH above 2.5 mIU/L. Free T4, TSH and insulin were measured with immunochemiluminescence assays (Immulite 2000). Basal plasma glucose, total cholesterol, HDL cholesterol and triglycerides were measured with automated methods (Technicon/Bayer RA 1000 Chemistry Analyzer). All measurements were performed from the same blood sample, obtained early in the morning after a minimum fasting period of 12 hours. Results: We found that the levels of insulin and HOMA-IR in group B were significantly lower that in group C (7.91 ± 0.67 mIU/L vs. 10.23 ± 0.91 mIU/L - p = 0.0073 and 1.84 ± 0.17 vs. 2.49 ± 0.27 - p = 0.0113, respectively). This difference was independent of age and BMI. In addition, we observed a slight but significant decrease in HDL-cholesterol levels in group C as compared to group B (48.3 ± 0.5 vs. 46.3 ± 0.7 mg/dl; p = 0.0455) and an increase in triglycerides (146.9 ± 11.9 vs. 112.3 ± 5.6 mg/dl; p = 0.0162). The prevalence of insulin resistance defined as a value of HOMA-IR higher than 2.5 was greater in group C compared to B (39.5 % vs. 23.9 %; OR 2.06 - IC 95 %: 1.19-3.63 - p = 0.013). Finally, a weak but significant negative correlation was observed between HOMA-IR and free T4 (r - 0.22276; p = 0.0059) and a positive correlation was observed between HOMA-IR and TSH (r = 0.1909; p = 0.0066) in the whole cohort. Conclusions: We conclude that in the studied population, patients with TSH above 2.5 mIU/L vs. those with TSH between 0.4 and 2.5 mIU/L presented: 1) lower levels of HDL cholesterol, 2) higher levels of triglycerides, insulin and HOMA-IR, independently of age and BMI and, 3) a significant increase in the risk of having insulin resistance measured by HOMA-IR.

Elevada frecuencia de enfermedad tiroidea funcional en embarazadas chilenas sin antecedentes de patología tiroidea utilizando el estándar de TSH internacional / Frequency of subclinical thyroid problems among women during the first trimester of pregnancy

Background: Thyroid hormones play an important role in fetal neural and cognitive development. Therefore thyroid abnormalities should be detected and treated early during pregnancy. Aim: To assess the frequency and risk factors for functional thyroid disorders during the first trimester of pregnancy. Material and Methods: A blood sample was obtained from women during their first trimester of pregnancy, consulting in a prenatal care facility. Women with known thyroid diseases were excluded from the study. Thyroid stimulating hormone (TSH), total thyroxine (T4) and free thyroxine (fT4) were measured by electrochemoluminiscence. Antithyroid peroxidase antibodies (anti TPO) were measured by enzyme immunoassay. Results: Five hundred and ten women aged 25.7 ± 6.6 years were assessed. The frequency of clinical hypothyroidism was 0.6%, subclinical hypothyroidism 35.3% and clinical hyperthyroidism 1%. Five percent of women with hypothyroidism and 3.5% of euthyroid women had positive anti TPO antibodies. There was no association between the frequency of thyroid diseases and risk factors for thyroid diseases. Conclusions: There is a high frequency of subclinical thyroid diseases among women consulting in this prenatal care clinic.

Hipotiroidismo adquirido en niños / Acquired hypothyroidism in childhood

El hipotiroidismo es una de las enfermedades endocrinas más frecuentes, sus manifestacionesse explican por la producción insuficiente de hormonas tiroideas o por su acción inadecuada en los órganos blanco. Según la causa, el hipotiroidismo se puede clasificar comocongénito o adquirido, y se puede originar de forma primaria en la glándula tiroidea por defectosen la síntesis y liberación hormonal, o de forma secundaria por alteraciones centrales en el eje hipotálamo-hipófisis-tiroides. La etiología y las características clínicas del hipotiroidismo en niñosy adolescentes difieren en parte de las presentadas en los adultos; por ello, es fundamental identificarlas manifestaciones particulares de la disfunción tiroidea durante la edad pediátrica, para lograr un diagnóstico y tratamiento oportunos, los cuales son esenciales para la prevención delas múltiples complicaciones, especialmente las secuelas neurológicas devastadoras y el retraso en el desarrollo. En este artículo se revisarán las principales características del hipotiroidismo adquirido en niños y adolescentes, planteándose a partir de un enfoque clínico simple y útil parala práctica médica general.

Hypothyroidism is one of the most frequent endocrine diseases; its signs and symptoms are explained by the inadequate production of thyroid hormones or their inadequate action in target tissues. According to the cause, hypothyroidism can be classified as congenital or acquired. It can arise as a primary dysfunction of the thyroid gland, in which there is a defect in thyroid hormone synthesis and hormonal release, or by a central defect from the hypothalamic-pituitary-thyroid axis.The etiology and clinical presentation of hypothyroidism in children and adolescents substantially differ from that in adults. Therefore, the identification of the specific clinical manifestations of thyroid dysfunction in childhood is fundamental to achieve an early diagnosis and treatment, which are essential to prevent multiple complications, especially devastating nervous system damage, anddevelopment delay. The aim of this review article is to describe the main characteristics of acquiredhypothyroidism in pediatric age, through a simple clinical approach, useful to the daily general medical practice.

Evaluación de la función tiroídea en pacientes pediátricos durante el uso de fármacos antiepilépticos / Assessment of thyroid in pediatric patients during the use of antiepileptic drugs

El objetivo principal de este trabajo es evaluar las alteraciones en la función tiroídea de pacientes pediátricos con epilepsia en tratamiento con fármacos antiepilépticos (FAEs). Un segundo objetivo es evaluar la severidad y manifestaciones clínicas de estas alteraciones y los FAEs asociados a ellas. Se revisó las historias clínicas de pacientes de 0-18 años, en control por epilepsia, pertenecientes a la unidad de Neuropsiquiatría Infantil del Hospital Dr. Lautaro Navarro Avaria de Punta Arenas, durante el periodo comprendido entre julio del 2008 y junio del 2009. Criterios de inclusión: estar en tratamiento con FAEs y tener registro de evaluación de función tiroídea en su ficha clínica. De los 59 pacientes que cumplieron con los criterios de inclusión, 21 tenían niveles de hormona tiro-estimulante (TSH) elevados, seis de ellos presentaron manifestaciones clínicas de hipotiroidismo. La mayoría presentó hipotiroidismo subclínico y recibía tratamiento con ácido valproico (VPA) como monoterapia. Es por esto y considerando que el desarrollo cerebral de los niños es altamente sensible a los niveles de tiroxina, parece fundamental el monitoreo de la función tiroídea en niños y adolescentes en tratamiento con FAES.

Our aim was to evaluate severity and clinical manifestations of thyroid function abnormalities in pediatric epileptic patients in therapy with antiepileptic drugs (AED). Medical histories of patients attending to the Pediatric Neuropsychiatric Unit of Dr. Lautaro Navarro Avaria Hospital, Punta Arenas were reviewed. Fifty nine epileptic patients aged between 0-18 years, on AED therapy between July 2008 and June 2009, with evaluation of thyroid function were included. Thyroid-stimulating hormone (TSH) serum levels were high in 21 of the 59 patients, six of them showed clinical signs of hypothyroidism. Most of them exhibited TSH values in the subclinical hypothyroidism range and were on valproic acid (VPA) monotherapy. Considering that children’s brain development is highly sensitive to thyroxine levels, we emphasize the relevance of monitoring thyroid function in children and adolescents receiving antiepileptic treatment.