Laboratorio de función tiroidea en pediatría. Ventajas y limitaciones de los métodos indirectos para la obtención de intervalos de referencia / Thyroid function laboratory in pediatrics. Advantages and limitations of indirect methods to obtain reference intervals

Obtener intervalos de referencia (IRs) confiables para pruebas de laboratorio en pediatría es particularmente complejo y costoso. Una alternativa a este problema es el uso de métodos indirectos, donde se usan grandes bases de datos preexistentes de pacientes. Nuestros objetivos fueron: calcular IR para TSH y hormonas tiroideas (Perfil tiroideo, PT) en población pediátrica que asiste al Hospital de Pediatría Juan P. Garrahan, por método indirecto y verificar la confiabilidad de los mismos para su aplicación. Se recolectaron datos de 19.842 pacientes entre enero de 2020 y diciembre de 2021. Se aplicaron filtros para eliminar los pacientes que pudieran tener afectado el PT. Los 4.861 pacientes incorporados al análisis fueron divididos en 3 grupos: G1: 0-12 meses (n: 551), G2:13 meses- 7 años (n: 1347) y G3: 8 -18 años (n: 2963). Los IR fueron calculados por 2 métodos: el de Hoffman adaptado y el de CLSI EP28A3, para cada grupo de edad. TSH, TT3 y T4L se analizaron con Architect i4000-Abbott y TT4 con Immulite 2000XPi-Siemens. Para la primera etapa de verificación se utilizaron 20 sueros de pacientes provenientes de análisis prequirúrgicos. Los outliers se detectaron aplicando el método de Tukey. Los datos fueron procesados según CLSI EP28A3c. Los IR obtenidos fueron similares a los previamente publicados obtenidos por método directo. Los resultados de la verificación fueron en su mayoría aceptados. Por lo tanto, los métodos indirectos son una buena alternativa de cálculo de IR en pediatría (AU)

Obtaining reliable reference ranges (RRs) for laboratory tests in pediatrics is particularly complex and costly. An alternative to this problem is to use of indirect methods, where large pre-existing patient databases are used. Our aims were to calculate RRs for TSH and thyroid hormones (thyroid profile, PT) in children seen at Hospital de Pediatría Juan P. Garrahan by indirect methods and to verify their reliability for their application. Data were collected from 19,842 patients seen between January 2020 and December 2021. Filters were applied to eliminate patients in whom the PT was potentially affected. The remaining 4,861 patients included in the analysis were divided into 3 groups: G1: 0-12 months (n: 551), G2: 13 months-7 years (n: 1347) and G3: 8-18 years (n: 2963). RRs were calculated by 2 methods: the adapted Hoffman method and the CLSI EP28A3 method, for each age group. TSH, TT3, and FT4 were analyzed with Architect i4000-Abbott and TT4 with Immulite 2000XPi-Siemens. For the first stage of verification, 20 patient sera from pre-surgical analysis were used. Outliers were detected by applying the Tukey method. The data were processed according to CLSI EP28A3c. The RRs obtained were similar to those previously published using the direct method. The verification results were mostly acceptable. Therefore, indirect methods are a good option for calculating RRs in children (AU)

Momento de administración de la levotiroxina en pacientes con hipotiroidismo / Timing of levothyroxine administration in patients with hypothyroidism

El hipotiroidismo primario, caracterizado por una disminución en la síntesis de hormonas tiroideas, es el trastorno endocrinológico más frecuente, y la levotiroxina, el tratamiento de elección. Usualmente se recomienda su administración por la mañana, una hora antes del desayuno. A partir de la consulta de una paciente con dificultades para la adherencia ala toma de la medicación en ayunas, la autora de este artículo lleva a cabo una búsqueda bibliográfica para revisar la evidencia que avala la administración de levotiroxina antes de acostarse. (AU)

Primary hypothyroidism, characterized by a decrease in the synthesis of thyroid hormones, is the most common endocrine disorder, and levothyroxine being the treatment of choice. Its administration is usually recommended in the morning, one hour before breakfast. Based on the consultation of a patient with difficulties in sticking to taking medication on an empty stomach, the author of this article carried out a bibliographic search to review the evidence that supports the administrationof levothyroxine before bedtime. (AU)

Medical treatment in pregnant women with subclinical hypothyroidism: systematic review and meta-analysis / Tratamiento médico en gestantes con hipotiroidismo subclínico: revisión sistemática y meta-análisis

Abstract Objectives: to determine the effectiveness of medical therapy in reducing complications associated with subclinical hypothyroidism during pregnancy. Methods: in 2021, a systematic review of available cohort studies was carried out in three databases, with no publication date limit. Study selection and data extraction were performed in duplicate. Random-effects meta-analysis was performed, and odds ratios were calculated, with the corresponding 95% confidence intervals. Cohort risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). The certainty of the evidence was assessed using the GRADE methodology. Results: five studies were included for qualitative and quantitative synthesis. A statistically significant relationship was found between medical treatment in pregnant women with subclinical hypothyroidism with respect to spontaneous abortion (p=0.03; OR=0.77; CI95%=0.61-0.97), and no statistically significant relationship was found for delivery preterm (p=0.46; OR=1.11; CI95%=0.85-1.44), nor for abrupt placentae (p=0.56; OR=1.60; CI95%=0.33-7.66). Three studies were at moderate risk of bias, and two were at low risk of bias. In all the results the certainty was very low. Conclusions: medical treatment of subclinical hypothyroidism during pregnancy can have a beneficial effect in reducing cases of spontaneous abortion.

Resumo Objetivos: determinar la efectividad de la terapia médica para disminuir las complicaciones asociadas al hipotiroidismo subclínico durante la gestación. Métodos: en el 2021 se realizó una revisión sistemática de estudios de cohortes disponibles en tres bases de datos, sin límite de fecha de publicación. La selección de estudios y extracción de datos se realizaron por duplicado. Se realizó metaanálisis de efectos aleatorios y se calcularon los Odds ratio, con los correspondientes intervalos de confanza al 95%. El riesgo de sesgo de las cohortes se evaluó mediante la escala de Newcastle-Ottawa (NOS). La certeza de la evidencia se evaluó con la metodología GRADE. Resultados: cinco estudios fueron incluidos para síntesis cualitativa y cuantitativa. Se encontró una relación estadísticamente significativa del tratamiento médico en gestantes con hipotiroidismo subclínico con respecto al aborto espontáneo (p=0,03; OR=0,77; IC95%=0,61-0.97), no se encontró relación estadísticamente significativa para parto pre término (p=0.46; OR=1,11; IC95%=0.85-1.44), ni para abrupto placentae (p=0.56; OR=1,60; IC95%=0.33-7.66). Tres estudios tenían riesgo moderado de sesgo, y dos tenían riesgo de sesgo bajo. En todos los resultados la certeza fue muy baja. Conclusiones: el tratamiento médico del hipotiroidismo subclínico durante la gestación puede tener un efecto beneficioso para reducir los casos de aborto espontaneo.

Approach to Subclinical Hypothyroidism in Adults / Abordaje del Hipotiroidismo subclínico en el Adulto

Thyroid pathology is the morphofunctional evolution of the thyroid glands that leads to different types of clinical pictures. Within it is subclinical hypothyroidism, which is a biochemical alteration due to the elevation of thyroid-stimulating hormone (TSH) between 4.5 to 10 mUI that can occur with or without symptoms of multifactorial origin. The worldwide prevalence is 4-10% and Latin America 15-25%. 90% of patients with this pathology do not require treatment, but in turn there is an overmedicalization and underdiagnosis of it. This bibliographic review analyzes from its morphofunctional changes towards clinical criteria for a comprehensive approach to subclinical hypothyroidism, where we have an individualization by its comorbidities, age group, diagnostic algorithm, follow-up and differentiated treatment according to recent studies within this pathology. Therefore, an adequate diagnosis, follow-up and treatment provides a better lifestyle for patients.

La patología tiroidea es la alteración morfofuncional de la glándula tiroides que lleva a diferentes tipos de cuadros clínicos. Dentro de ella se encuentra el Hipotiroidismo subclínico que es una alteración bioquímica por la elevación de la Hormona Estimulante de la tiroides (TSH) entre 4,5 a 10 mUI que puede presentarse con o sin sintomatología y tiene etiología multifactorial. La prevalencia mundial es del 4-10 % y latinoamericana del 15-25%. El 90% de pacientes con esta patología no requieren tratamiento, pero a su vez existe una sobremedicalización y una subdiagnóstico del mismo. La presente revisión bibliografía analiza a partir de su alteración morfofuncional hacia criterios clínicos para un abordaje integral del Hipotiroidismo subclínico, donde tenemos una individualización por sus comorbilidades, grupo etario, algoritmo diagnóstico, seguimiento y tratamiento diferenciado según últimos estudios dentro de esta patología. Por lo que un adecuado diagnóstico, seguimiento y tratamiento brinda un mejor estilo de vida a los pacientes.

Atipicidad en el hipotiroidismo congénito: síndrome de Kocher-Debré-Semelaigne. Reporte de caso / Atypicality in congenital hypothyroidism: Kocher-Debré-Semelaigne. Case report

El síndrome de Kocher Debré Semelaigne (SKDS) se describe dentro de las formas clínicas atípicas asociadas al hipotiroidismo congénito (HC) severo, no tratado y de larga evolución, con manifestaciones de pseudohipertrofia muscular difusa y debilidad muscular predominantemente proximal, reversible al reemplazo con tiroxina. Es raro en países con programas de pesquisa neonatal. Objetivo: reportar el caso de un niño con diagnóstico de HC por disembriogenesis (atireosis), que se mantuvo con mal control de la enfermedad durante el primer año de vida y manifestaciones miopáticas desde la etapa neonatal. Resultados: se confirma el diagnóstico a través de estudios específicos, con evidencias de patrones miopáticos característicos. Se logra regresión clínica parcial a los nueve meses de mantener estabilidad de la TSH y las hormonas tiroideas (HT), coincidiendo con la normalización de la enzima de músculo creatinfosfoquinasa (CPK). A los 12 años de seguimiento, mantenía ligera hipertrofia de la musculatura de las extremidades superiores, dorsales y glúteos, a pesar de mantenerse eutiroideo. Conclusiones: la presencia de hipertrofia muscular debe considerarse un dato clínico de sospecha de hipotiroidismo, aun con la implementación de los programas de pesquisa neonatal. Es posible la regresión parcial de la pseudohipertrofia muscular con el restablecimiento de la función tiroidea. Se debe tomar en cuenta en el diagnóstico diferencial de otras miopatías primarias

Kocher-Debré-Semelaigne Syndrome (SKDS) is described within the atypical clinical forms associated with severe, untreated and long-standing congenital hypothyroidism with manifestations of diffuse muscle pseudohypertrophy and predominantly proximal muscle weakness, reversible to replacement with levothyroxine. objective: To report the case of a child with congenital hypothyroidism due to disembriogenesis (atyreosis), who remained with poor control of the disease during the 1st year of life and myopathic manifestations from de neonatal stage. Results: The diagnosis is confirmed through specific studies, with evidence of characteristic myopathic patterns. Partial clinical regression is achieved 9 months after maintaining stability of TSH and thyroid hormones, coinciding with the normalization of the muscle enzyme creatine phosphokinase (CPK). At 12 years of follow-up, he maintained slight hypertrophy of the muscle of the upper extremities, dorsal and buttocks, despite remaining euthyroid. Conclusions: The presence of muscular hypertrophy should be considered a clinical finding of suspected hypothyroidism, even with the implementation of neonatal screening programs. Partial regression of muscle pseudohypertrophy is possible with restoration of thyroid function, and should be taken into account in the differential diagnosis of other primary myopathies

Elementos básicos para el diagnóstico y manejo terapéutico del coma mixedematoso en el paciente adulto / Basic elements for the diagnosis and therapeutic management of myxedematous coma in adult patients

Introducción: A pesar de su baja incidencia, la gravedad del cuadro clínico y la alta mortalidad hacen del coma mixedematoso una complicación a tener en cuenta. Objetivo: Describir los elementos básicos para el diagnóstico y manejo terapéutico del coma mixedematoso en el paciente adulto. Métodos: Se realizó una búsqueda de literatura relevante sobre el tema. Se utilizaron buscadores de información científica como Pubmed y Google Académico. La estrategia de búsqueda incluyó los siguientes términos como palabras clave: hipotiroidismo primario, hipotiroidismo subclínico, diagnóstico y tratamiento. Fueron evaluados artículos de revisión, de investigación y páginas web que tuvieran menos de 10 años de publicados. Se consideraron los textos en idioma español e inglés y que hicieran referencia específicamente al tema de estudio a través del título. Fueron excluidos los artículos que no cumplieron con estas condiciones. Esto permitió el estudio de 64 artículos, de los cuales 40 fueron referenciados. Conclusiones: Para el diagnóstico del coma mixedematoso en el paciente adulto lo más importante es sospecharlo en aquellas personas que presenten factores precipitantes, acompañados de síntomas y signos de hipotiroidismo severo con diferentes grados de insuficiencia del sistema nervioso central, hipotermia, hipoventilación, insuficiencia circulatoria e hiponatremia. A esto se sumaría el escenario humoral característico y los posibles hallazgos dependientes de la enfermedad causante del hipotiroidismo. Se debe tratar con un reemplazo agresivo de levotiroxina sódica (vía endovenosa u oral, según posibilidades), unido a otras medidas de apoyo en el entorno hospitalario(AU)

Introduction: Despite its low incidence, the severity of the clinical picture and the high mortality make myxedematous coma a complication to be taken into account. Objective: Describe the basic elements for the diagnosis and therapeutic management of myxedematous coma in adult patients. Methods: A search of relevant literature on the subject was carried out. Pubmed and Google Scholar were used as search engines for scientific information. The search strategy included the following keyword terms: primary hypothyroidism, subclinical hypothyroidism, diagnosis and treatment. Review articles, research articles and Web pages that, in general, had less than 10 years of publication, in Spanish and English that specifically referred to the subject of study through the title were evaluated. Articles that did not meet these conditions were excluded. This allowed the study of 64 articles, of which 40 were referenced. Conclusions: For the diagnosis of myxedematous coma in the adult patient, the most important thing is to suspect it in those people who present precipitating factors, accompanied by symptoms and signs of severe hypothyroidism with different degrees of central nervous system insufficiency, hypothermia, hypoventilation, circulatory insufficiency and hyponatremia. To this would be added the characteristic humoral scenario and the possible findings dependent on the disease causing hypothyroidism. It should be treated with an aggressive replacement of levothyroxine sodium (intravenous or oral way, accodring to the possibilities), together with other supportive measures in the hospital setting(AU)

Doença de Graves e sua recidiva: relato de caso / Grave's disease and its relapse: case repor

A doença de Graves (DG) é uma patologia autoimune que acomete a glândula tireoide e é a causa mais comum de hipertireoidismo. O principal grupo acometido por DG são as mulheres. Sendo assim, relatamos caso de paciente com 52 anos, do sexo feminino, com diagnóstico de Doença de Graves, que caracteriza quadro de hipertireoidismo. A paciente iniciou tratamento com tapazol (tiamazol) durante um ano e realizou pausa, recomendada pelo médico. No entanto, a paciente não retratou melhora e iniciou sintomatologia semelhante a dengue, como mal estar geral e fadiga muscular. Assim, realizou procura médica, e, inicialmente, foi diagnosticada com quadro de dengue, mas não houve melhora dos sintomas e procurou, portanto, endocrinologista. Realizou novos exames e foi confirmado quadro recidivo de Doença de Graves. Dessa maneira, iniciou novo tratamento. O estudo tem como objetivo relatar e discutir quadro de Doença de Graves associada a hipertireoidismo

Grave's disease (DG) is an autoimmune pathology that affects the thyroid gland and it's the most commom cause of hipertireoidism. The main group affected by DG are woman. That way we related a case of patient with 52 years, female with the diagnose of Grave's disease, that shows a patient conditioning of hipertireoidism. The patient began the treatment with tapazol during a year and made a pause recommended by the doctor. Therefore the patient didn't indicate progress and started a symptomatology similar to dengue fever, as general malaise and muscle fatigue. There by the patient searched for a doctor and initially was diagnosed with a patient conditioning of dengue fever, but she didn't manifested a improving of symptoms, and then searched for an endocrinologist. Realized then new exams and a recurrence case of grave´s disease was confirmed. This way the patient started a new treatment. Thus, the present study aims to report and discuss Graves' disease associated with hyperthyroidism.

Urgencias endocrinológicas: coma mixedematoso / Endocrine emergencies: myxedema coma

Introducción: en el presente reporte de caso se presenta una urgencia endocrinológica, el coma mixedematoso. Se considera una descompensación del hipotiroidismo y su mortalidad es alta alcanzando hasta 52% en algunas series de casos. Puede desencadenarse por múltiples factores y su presentación clínica es muy variada ya que comprende la afección de diversos sistemas. Presentación del caso: se presenta el caso de una paciente femenina de 42 años de edad que consultó al servicio de urgencias del Hospital de San José de Bogotá con sospecha inicial de una de falla cardiaca descompensada, sin embargo, cursó con pobre mejoría ante el manejo instaurado, por lo cual se realizaron estudios de extensión en donde se encontró una función tiroidea deprimida. Discusión y conclusiones: en este momento se consideró que la paciente padecía un coma mixedematoso, se instauró manejo con dosis altas de levotiroxina oral con lo cual evolucionó de manera favorable y se logró dar de alta a los pocos días.

Introduction: herein we present an endocrine emergency, myxedema coma, which is a form of decompensated hypothyroidism, whose mortality may be as high as 52% as evidenced in some case series. It may be triggered by multiplefactors and has varied clinical presentations for it affects diverse organ systems. Case presentation:we present the case of a 42-year-old female who presented to the emergency department of Hospital de San José in Bogotá with clinical suspicion of decompensated heart failure upon admission, however, her response was poor to the treatment she received. Extension studies were performed which showed low thyroid function. Discussion and conclusions: at this point the patient was diagnosed with myxedema coma, and was started on high doses of oral levothyroxine, with which she evolved favorably and was discharged a few days later.

¿El tratamiento del hipotiroidismo subclínico tiene efecto sobre la morbimortalidad cardiovascular? / Does treatment of subclinical hypothyroidism have an effect on cardiovascular morbidity and mortality?

Un estudio mostró que el aumento de valores de la hormona estimulante de la tiroides se asoció a un aumento de mortalidad por todas las causas, estimando que las enfermedades cardiovasculares mediaban dicha asociación en aproximada-mente el 14 % de los casos. Asimismo se observó que el reemplazo con levotiroxina disminuiría los niveles de colesterol, lo cual podría tener un efecto en la reducción de enfermedades cardiovasculares. Partiendo de una viñeta clínica la autora intenta, a través de una búsqueda bibliográfica y análisis de la evidencia, determinar si el tratamiento del hipotiroidismo subclínico en adultos mayores reduciría la morbimortalidad por eventos cardiovasculares. (AU)

A study showed that increased thyroid-stimulating hormone levels were associated with increased all-cause mortality, with cardiovascular disease estimated to mediate this association in approximately 14 % of cases. Additionally, levothyroxine replacement was found to lower cholesterol levels, which could have an effect in reducing cardiovascular diseases. Basedon a clinical vignette, the author attempts, through a literature search and an analysis of the evidence, to determine whether treatment of subclinical hypothyroidism in older adults would reduce morbidity and mortality from cardiovascular events. (AU)

Use of combination of Oral Levothyroxine and Liothyronine in severe Hypothyroidism with Massive Pericardial Effusion / Journal of the ASEAN Federation of Endocrine Societies

@#Thyroid hormone plays an important role in cardiovascular function. Pericardial effusions are commonly seen in cases of severe hypothyroidism. However, large to massive pericardial effusions with cardiac tamponade are exceptionally rare. Herein, we present two cases of severe hypothyroidism with massive pericardial effusion. Our first case demonstrates that a patient with large pericardial effusion can be managed conservatively with aggressive thyroid hormone replacement therapy. In our second case, pericardiocentesis was performed in addition to thyroid hormone replacement therapy as the underlying aetiology of effusion could not be reasonably limited to hypothyroidism. These two cases served to highlight and demonstrate rapid normalisation of thyroid function test by using aggressive oral thyroid hormone replacement therapy using liothyronine, in combination with levothyroxine, which led to resolution of pericardial effusion and prevent its re-accumulation.

Hiperplasia de hipófise secundária a hipotireoidismo primário - relato de caso / Pituitary hyperplasia secondary to primary hypothyroidism - case report

A hiperplasia hipofisária é definida como um aumento não neoplásico no número de um dos tipos de células presentes na hipófise. Ela pode ocorrer por um processo fisiológico ou patológico. O hipotireoidismo primário prolongado é uma das causas patológicas desta condição, e ocorre devido a perda do feedback negativo. O objetivo desse relato foi demonstrar a presença de hiperplasia hipofisária em um paciente masculino com características corporais sugestivas de acromegalia. A investigação laboratorial confirmou a presença de hipotireoidismo primário e descartou a acromegalia. Foi instituído tratamento com levotiroxina, levando a regressão da hiperplasia hipofisária. Esse caso ilustra a importância de uma investigação apropriada em pacientes com hiperplasia hipofisária, bem como discute a fisiopatologia e o tratamento dessa doença.

Pituitary hyperplasia is defined as a non-neoplastic increase in the number of one of the cell types present in the pituitary gland. It can occur by a physiological or pathological process. Prolonged primary hypothyroidism is one of the pathological causes of this condition and occurs due to the lack of negative feedback. The objective of this report was to demonstrate the presence of pituitary hyperplasia in a male patient with body characteristics suggestive of acromegaly. Laboratory investigation confirmed the presence of primary hypothyroidism and ruled out acromegaly. Treatment with levothyroxine was instituted, leading to regression of pituitary hyperplasia. This case illustrates the importance of an appropriate investigation in patients with pituitary hyperplasia, as well as discussing the pathophysiology and treatment of this disease.

Transient hypothyroxinemia of prematurity and its risk factors in an extramural neonatal intensive care unit

ABSTRACT Objective: Thyroid functions in preterm newborns may be altered in the first week of life. Hypothyroxinemia has been commonly reported in these babies, which could be due to the immaturity of the hypothalamic pituitary thyroid axis or acute illness. It could have a long-term impact on the developing brain of these babies. We conducted this study to estimate the incidence of transient hypothyroxinemia of prematurity (THOP) and to determine its risk factors. Materials and methods: We analyzed thyroid stimulating hormone (TSH) and free T4 levels of 64 preterm neonates admitted in the neonatal intensive care unit. TSH and free T4 levels were measured in the first week and then at 14-21 days of life to estimate the incidence of THOP and determine its risk factors. We also estimated the incidence of congenital hypothyroidism (CH) and delayed TSH elevation in CH. Risk analysis was conducted using simple and multiple logistic regression, and numerical data was compared using the Mann Whitney U test and t test. Results: THOP was seen in 25% of the preterm babies. Caesarean delivery, presence of one or more morbidities, mechanical ventilation, birth weight ≥ 1,500 g, and gestational age ≥ 32 weeks were identified as risk factors for THOP based on simple logistic regression. In multiple regression, mechanical ventilation and gestational age ≥ 32 weeks were significantly associated with THOP. CH was seen in 2 (3.1%) babies, and 1 of these cases had delayed TSH elevation. Conclusion: Thyroid abnormalities are common in preterm admitted neonates. Mechanical ventilation is an independent risk factor for development of THOP.

Hipotiroidismo subclínico en el embarazo / Subclinical hypothyroidism in pregnancy

Las alteraciones de la función tiroidea incluida el hipotiroidismo subclínico son unas de las patologías más frecuentes durante el embarazo, y se asocian a importantes complicaciones maternas, fetales y neonatales. Se han desarrollado múltiples guías de práctica clínica por sociedades internacionales en busca de unificar el enfoque diagnóstico y terapéutico de las patologías tiroideas durante la gestación, sin embargo hay evidencia insuficiente sobre la realización de tamizaje y aún más sobre las intervenciones terapéuticas en caso del hipotiroidismo subclínico, se presenta la siguiente revisión de la literatura para vislumbrar a la luz de información actualizada como realizar el abordaje integral de las pacientes gestantes con hipotiroidismo subclínico (AU)

Alterations in thyroid function, including subclinical hypothyroidism, are one of the most frequent pathologies during pregnancy, and are associated with important maternal, fetal, and neonatal complications. Multiple clinical practice guidelines have been developed by international societies in search of unifying the diagnostic and therapeutic approach of thyroid pathologies during pregnancy, however there is insufficient evidence on screening and even more on therapeutic interventions in case of subclinical hypothyroidism , the following review of the literature is presented to envision in the light of updated information how to carry out a comprehensive approach to pregnant patients with subclinical hypothyroidism (AU)

A trial for improving thyroid gland dysfunction in rats by using a marine organism extract / Tentativa para melhorar a disfunção da glândula tireoide em ratos usando um extrato de organismo marinho

Abstract Understanding the relation between the environmental stress factors and the hypothalamus-pituitary-thyroid (HPT) axis efficiency can reduce the susceptibility to thyroid diseases. In our study, thyroid dysfunction was induced in female rats by administration of 40 mg Na F/kg.bd.wt/day for a month. Co-administration of the water extract of Arca noae (300 mg/kg. bw) was tested as a treatment for Na F induced thyroid dysfunction. A group of rats injected Arca noae extract only (300 mg/kg.bd.wt) was performed to observe the impact of the extract on the (HPT) axis in addition to the normal control group. Results showed that there was a significant decrease in serum triglycerides, total protein and albumin levels in the fluoride supplemented group in addition to abnormal levels of TSH, (T4) and (T3) compared to the control group. In the treated group there was an improvement in the proteins level and lipid profile but pseudo-corrected serum (T4) and (T3) levels were observed in addition to a continuous increase in TSH level. Histological findings confirmed the harmful effect of fluoride on both the non treated and the treated groups. Consequently, fluoride supplementation must be considered as a harmful stress that may affect permanently the HPT axis.

Resumo Compreender a relação entre os fatores de estresse ambiental e o eixo hipotálamo-hipófise-tireoide (HPT) pode reduzir a suscetibilidade a doenças da tireoide. Em nosso estudo, a disfunção tireoidiana foi induzida em ratos fêmeas pela administração de 40 mg Na F/kg.bw/dia durante um mês. A administração concomitante do extrato aquoso de Arca noae (300 mg/kg.Pc) foi testada como tratamento para a disfunção tireoidiana induzida por Na F. Um grupo de ratos injetados apenas com extrato de Arca noae (300 mg/kg. Pc) foi pré-formado com o intuito de observar o impacto do extrato no eixo (HPT), além do grupo controle normal. Os resultados mostraram que houve uma diminuição significativa nos níveis séricos de triglicerídeos, proteína total e albumina no grupo suplementado com fluoreto, além de níveis anormais de TSH, (T4) e (T3) em comparação ao grupo controle. No grupo tratado, houve uma melhora no nível de proteínas e perfil lipídico. Os níveis séricos pseudocorrigidos (T4) e (T3) foram observados, além de um aumento contínuo no nível de TSH. Os achados histológicos confirmaram o efeito prejudicial do flúor nos grupos não tratado e tratado. Consequentemente, a suplementação de flúor é considerada um estresse prejudicial que pode afetar permanentemente o eixo HPT.

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.

Nutritional and quality changes in piglet concentrate affected by the mix / [Mudanças nutricionais e de qualidade no concentrado de leitão afetadas pela mistura]

The aim of this study was to evaluate the reasons of quality deviation of a concentrate from a predefined standard. Five treatments were established: T1 - Control, standard concentrate formulation (SCF); T2 - PXMore5, SCF with more 5% vitamin-mineral premix (VMP); T3 - PXLess5, SCF with less 5% VMP. All three treatments used a 400kg batches in an INTECNIAL mixer; T4 - FeedMixer, SCF using a 4,000kg batch in an IMOTO mixer; T5 - PremixMixer, SCF using a 1,200kg batch in an MUYANG mixer. For each treatment, bags of 20 kg were stored in three storage places for four months. Water activity of concentrate was affected by temperature and air relative humidity in different storage places. Regarding the kind of mixer, the greatest variation in concentration of crude protein, mineral residue, copper, zinc, and selenium was observed in the PremixMixer. Adjustments are imperative in the handling and use procedures of this kind of mixer to meet the quality requirements required in the concentrate production. Analyzing the effect of the mineral-vitamin premix level, no difference could be defined with the evaluated parameters.(AU)

O objetivo deste estudo foi avaliar as razões do desvio de qualidade de um concentrado de um padrão predefinido. Foram estabelecidos cinco tratamentos: T1 - controle, concentrado com formulação padrão (CFP); T2 - PXMais5, CFP com 5% a mais de vitaminas e minerais da pré-mistura (PVM); T3 - PXMenos5, CFP com 5% a menos de PVM. Todos esses três tratamentos utilizaram lotes de 400kg em um misturador INTECNIAL; T4 - FeedMixer, CFP usando um lote de 4.000kg em um misturador IMOTO; T5 - PremixMixer, CFP usando um lote de 1.200kg em um misturador MUYANG. Para cada tratamento, sacos de 20kg foram armazenados em três ambientes distintos por quatro meses. A atividade de água do concentrado foi afetada pela temperatura e umidade relativa do ar em diferentes locais de armazenamento. Em relação ao tipo de misturador, a maior variação na concentração de proteína bruta, resíduo mineral, cobre, zinco e selênio foi devido ao PremixMixer. Ajustes são imperativos nos procedimentos de manuseio e uso desse tipo de misturador para atender aos requisitos de qualidade exigidos na produção de concentrado. Ao se analisar o efeito do nível da pré-mistura de vitaminas e minerais, nenhuma diferença pôde ser definida com os parâmetros avaliados.(AU)

A practical contemporary approach to decision-making on subclinical hypothyroidism

ABSTRACT Subclinical hypothyroidism (Shypo) is an increasingly frequent condition in common medical practice. Its diagnosis continues to pose a challenge since a series of non-thyroidal and temporary conditions can elevate serum TSH levels. In addition, the consequences of Shypo are still up for debate. Although detrimental cardiovascular effects have been consistently demonstrated in the young, they are less evident in older adults (65-79 years), and even more so in the oldest old (≥80 years). In the absence of evidence of any benefits of treating Shypo in patients' clinical manifestations and unfavorable outcomes, the most effective decision-making approach should include a thorough investigation of the patient's condition integrating all relevant clinical data, such as TSH levels, age, quality of life, comorbidities, cardiovascular risk, safety, and personal preferences. The decision-making process needs to take into account the risk of levothyroxine overtreatment and the resulting adverse consequences, such as reduction of bone mineral density, heart failure, and atrial fibrillation. Hence, current evidence suggests that individuals with TSH > 10 mU/L, who test positive for TPO Ab or are symptomatic may benefit from levothyroxine treatment. However, a more cautious and conservative approach is required in older (≥65 years of age), and oldest-old (≥80 years) patients, particularly those with frailty, in which the risk of treatment can outweigh potential benefits. The latter may benefit from a wait-and-see approach.

Subcutaneous administration of levothyroxine: a novel approach to refractory hypothyroidism - A review and a case report

SUMMARY Treatment-refractory hypothyroidism is a common clinical finding. Substantial causes include poor compliance and intake failure as well as gastrointestinal diseases, such as inflammatory bowel disease and short bowel syndromes. Increasing oral dosage of levothyroxine (LT4) is not always effective. Therefore, alternative routes of administration are necessary. In this report, we evaluate alternative treatment modalities for refractory hypothyroidism and present a 28-year-old woman with intestinal drug malabsorption successfully treated by subcutaneous LT4 administration. In this patient, a parenteral form of LT4, 500 μg/5 ml, was administered subcutaneously in a split dosage regimen. Blood hormone levels returned to normal within a few days and remained stable over an 8-month follow-up period.