Elementos básicos para el diagnóstico y manejo terapéutico del hipotiroidismo primario en el paciente adulto

Introducción: El hipotiroidismo primario, con frecuencia, es diagnosticado de forma tardía y no siempre las dosis indicadas de levotiroxina son las más convenientes. Urge llamar la atención sobre estos aspectos y actualizar el conocimiento sobre este tema. Objetivo: Describir los elementos básicos para el diagnóstico y manejo terapéutico del hipotiroidismo primario en el paciente adulto, en el primer nivel de atención. Métodos: Se realizó una búsqueda de literatura relevante sobre el tema. Se utilizaron como buscadores de información científica a Pubmed y a Google Académico. La estrategia de búsqueda incluyó los siguientes términos como palabras claves: hipotiroidismo primario; hipotiroidismo subclínico; diagnóstico y tratamiento. Fueron evaluados artículos que, en general, tenían menos de 10 años de publicados, en idioma español e inglés, que hicieran referencia específicamente al tema de estudio a través del título. Fueron excluidos los artículos que no cumplieron con estas condiciones. Esto permitió que 72 fueran referenciados. Conclusiones: Para realizar el diagnóstico del hipotiroidismo primario, es fundamental conocer los factores de riesgo y el cuadro clínico correspondiente. La elevación de la tirotropina en suero es la mejor prueba diagnóstica y casi siempre indica la presencia de hipotiroidismo primario. Se debe tener presente al inicio del tratamiento, la edad del paciente, el tiempo de evolución de la enfermedad, la intensidad del hipotiroidismo, el momento fisiológico y la presencia de enfermedades asociadas. Todos los pacientes con hipotiroidismo primario manifiesto deben ser tratados con levotiroxina sódica, pero aquellos con hipotiroidismo subclínico no siempre se benefician con este tratamiento.

Introduction: Primary hypothyroidism is often diagnosed lately and not always are the indicated doses of levothyroxine the most convenient. It is urgent to draw attention towards these aspects and to update knowledge on this subject. Objective: To describe the basic elements for the diagnosis and therapeutic management of primary hypothyroidism in adult patients at the first level of care. Methods: A search for relevant literature on the subject was carried out. Pubmed and Google Scholar were used as search engines for retrieving scientific information. The search strategy included the following terms as keywords: hipotiroidismo primario [primary hypothyroidism], hipotiroidismo subclínico [subclinical hypothyroidism], diagnóstico y tratamiento [diagnosis and treatment]. Generally speaking, articles within ten years of having been published were assessed, written in Spanish and English and making a specific reference to the subject of the study in their respective titles. Articles not meeting these conditions were excluded. This allowed for 72 articles be referenced. Conclusions: To make the diagnosis of primary hypothyroidism, it is essential to know the risk factors and the corresponding clinical picture. Serum thyrotropin elevation is the best diagnostic test and almost always indicates the presence of primary hypothyroidism. The patient's age, the time of evolution of the disease, the intensity of the hypothyroidism, the physiologic time and the presence of associated diseases should be taken into account at the beginning of treatment. All patients with overt primary hypothyroidism should be treated with levothyroxine sodium, but those with subclinical hypothyroidism do not always benefit from this treatment.

Síndrome de Van Wyk-Grumbach / Van Wyk-Grumbach syndrome

RESUMEN El síndrome de Van Wyk-Grumbach se caracteriza por hipotiroidismo primario de larga duración asociado a pubertad precoz. Se presenta una paciente de 7 años, mestiza, que acude por sangrado vaginal, acompañado de hiperpigmentación de las areolas sin galactorrea, abdomen globuloso, mixedema, hirsutismo, baja talla, astenia y retraso escolar. La química sanguínea mostró anemia, hipercolesterolemia y hipertransaminasemia; los estudios de imágenes constataron derrame pericárdico, retraso marcado de la edad ósea, incremento de las dimensiones de la silla turca y gran quiste del ovario con aparente criterio quirúrgico. Los estudios hormonales confirmaron la sospecha de hipotiroidismo primario asociado a hiperprolactinemia. El tratamiento sustitutivo con levotiroxina sódica revirtió los signos y síntomas de pubertad precoz, lo que evitó la cirugía del quiste de ovario; la recuperación en el ambiente escolar y social fue indiscutible. Reconocer esta entidad evita tratamientos absolutamente contraindicados, como la extirpación de los quistes o el tratamiento quirúrgico de la hiperplasia hipofisaria(AU)

ABSTRACT Van Wyk-Grumbach syndrome is characterized by long-lasting primary hypothyroidism associated with precocious puberty. A case of a 7-year-old female mestizo patient is reported. She came to consultation for vaginal bleeding, accompanied by hyperpigmentation of the areolas without galactorrhea, globular abdomen, myxedema, hirsutism, short stature, asthenia and school delay. Blood chemistry showed anemia, hypercholesterolemia and hypertransaminasemia. Imaging studies showed pericardial effusion, marked delay in bone age, increased dimensions of Turkish chair and large ovarian cyst with apparent surgical criteria. Hormonal studies confirmed the suspicion of primary hypothyroidism associated with hyperprolactinemia. Substitute treatment with levothyroxine sodium reversed the signs and symptoms of precocious puberty, which prevented ovarian cyst surgery; the recovery in the school and social environment was certain. Recognizing this entity avoids absolutely contraindicated treatments, such as the removal of cysts or the surgical treatment of pituitary hyperplasia(AU)

Hipotiroidismo refractario idiopático: un caso clínico / Idiopathic refractory hypothyroidism: case report

Introducción: El hipotiroidismo constituye una patología frecuente, y su tratamiento habitual es el suplemento de levotiroxina (LT4) oral (VO). Sin embargo, existen casos inhabituales donde no es posible corregir esta condición a pesar de la utilización de LT4 en dosis alta. El hipotiroidismo refractario se define como la persistencia del hipotiroidismo a pesar del uso de LT4 > 1,9 ug/kg/día. La prevalencia del hipotiroidismo refractario no ha sido suficientemente documentada hasta ahora. Descripción del caso: Mujer de 53 años con antecedentes de hipotiroidismo, obesidad, dislipidemia, hipertensión arterial e insulinorresistencia. Fue derivada desde APS a nivel terciario por hipotiroidismo persistente a pesar del uso de LT4 800 ug/día y liotironina 80 ug/día. En forma ambulatoria se descartaron distintas causas, como mala adhesión al tratamiento, pseudo-malabsorción, síndromes de malabsorción; interacciones farmacológicas o interacciones alimentarias. Ante esto, y manteniéndose en su condición, se decide hospitalizar. Durante la hospitalización se prueban distintas fórmulas de administración. Finalmente, se logra respuesta adecuada con LT4 por vía rectal 100 ug/día asociado a 100 ug c/12 horas VO. Discusión: A pesar de no contar con herramientas óptimas para enfrentar este caso, se logró aplicar una estrategia sistemática especializada, que permitió un buen manejo de la paciente. Luego de probar distintas formulaciones de hormonas tiroideas, se logró respuesta mediante la administración por vía rectal, lo cual sugiere que esta paciente presentaba algún trastorno celular/bioquímico intestinal alto, que impedía la absorción óptima de LT4 VO. Conclusiones: La principal fortaleza de este trabajo consiste en la demostración de la utilidad práctica, en un contexto de recursos limitados, de una estrategia de estudio y tratamiento sistemático del hipotiroidismo refractario, lo cual ha sido escasamente publicado en la literatura internacional. Además, se recalca la importancia de una intervención especializada oportuna para evitar los riesgos sistémicos asociados a dosis altas de hormonas tiroideas.

Introduction: Hypothyroidism is a common condition, and its usual treatment is the supplement of oral levothyroxine (po). However, there are unusual cases where it is not possible to correct this condition despite the use of high-dose levothyroxine. Refractory hypothyroidism is defined as the persistence of hypothyroidism despite the use of levothyroxine > 1.9 ug/kg/ day. The prevalence of refractory hypothyroidism has not been sufficiently documented so far. Case description: 53 year old woman with a history of hypothyroidism, obesity, dyslipidemia, hypertension and insulin resistance. She was sent from primary care to tertiary level due to persistent hypothyroidism despite the use of 800 ug/day levothyroxine and liothyronine 80 ug/ day. On an outpatient basis, different causes were excluded as poor adherence to treatment, pseudo-malabsorption, malabsorption syndromes; drug interactions or food interactions. Given this, and staying on her condition, it was decided to hospitalize. Different forms of administration were tested during hospitalization. Finally, got adequate response with levothyroxine rectally 100 ug/day associated with 100 ug po bid. Discussion: Despite not having optimum tools to deal with this case, it was succeeded thanks to the implementation of a specialized systematic strategy. After testing different formulations of thyroid hormones, a positive response by rectal administration was achieved, which suggests that this patient presented any high intestinal cell/biochemist disorder that prevented the optimal absorption of levothyroxine po. Conclusions: The main strength of this work consists in demonstrating the practical utility, in a context of limited resources, of a study and systematic treatment strategy of refractory hypothyroidism, which has barely been published in the international literature. It is also highlighted the importance of an early specialized intervention to prevent the systemic risks associated with high doses of thyroid hormones.

Avaliação terapêutica e posológica da levotiroxina sódica em cães com hipotiroidismo primário adquirido / L-levothyroxine therapeutic dosage evaluation in dogs with primary hypothyroidism

O hipotireoidismo primário adquirido é uma endocrinopatia frequentemente diagnosticada na espécie canina. A terapia consiste na suplementação oral com levotiroxina sódica (L-tiroxina), no entanto vários protocolos terapêuticos têm sido propostos pela literatura, com doses variando 11 a 44µg/kg uma a duas vezes ao dia, visto à grande variabilidade de absorção e meia-vida plasmática do fármaco. Foram estudados 30 cães com hipotiroidismo primário adquirido (13 machos e 17 fêmeas, idade média de 7,9±1,9 anos e peso médio de 19,1±12,6 kg) atendidos no Hospital Veterinário da Universidade Guarulhos (UnG) e no Serviço de Endocrinologia de duas clínicas particulares da cidade de São Paulo (2009-2011), com o objetivo de avaliar a posologia e a frequência de administração da L-tiroxina, mais frequentemente utilizada, capaz de garantir um controle terapêutico satisfatório, avaliado através dos sinais clínicos e do teste pós-tiroxina, além de correlacionar a dose de tiroxina empregada com o peso dos animais. A dose média de tiroxina utilizada em nossa casuística foi de 16,9±3,1µg/kg, sendo a frequência de administração a cada 12 horas em 50% dos casos. Para se investigar uma possível correlação entre o peso e a dosagem de tiroxina utilizada, uma vez que cães de pequeno porte apresentam maior taxa metabólica que cães de grande porte, os animais foram agrupados em grupo A, cães com peso <10 Kg (n=12/30; 7,7±2,1 kg) e grupo B, cães com peso >10 kg (n=18/30, 26,8±10,7 kg). A dose média de tiroxina empregada nos grupos A e B não apresentaram diferença estatística e foram, respectivamente, 16±3µg/kg e 17±3µg/kg. A frequência de administração foi 50% a cada 24 horas e 50% a cada 12 horas para ambos os grupos. Dessa forma, a dose de tiroxina não parece se correlacionar com o peso do animal, sendo imprevisível quem deverá receber dose e frequência máxima da medicação. O protocolo deve ser individualizado e o paciente devidamente monitorado.

The acquired primary hypothyroidism is a frequently diagnosed endocrinopathy in dogs. The therapy constitutes in oral supplementation with sodium levothyroxine (L-thyroxine), however various therapeutic protocols have been proposed in the literature, with doses ranging from11 to 44mg/kg once or twice a day, since L-thyroxine has a great variability of absorption and plasma half life. We studied 30 dogs with primary hypothyroidism (13 males and 17 females, mean age 7.9±1.9 years and mean weight of 19.1±12.6 kg), in order to evaluate the dose and frequency of administration of L-thyroxine used more often able to secure a satisfactory therapeutic control as measured by clinical signs and test post-pill, and to correlate the amount of thyroxine employed with the animals' weight. The mean dose of thyroxine used in our study was 16.9±3.1mg/kg, and the frequency of administration every 12 hours in 50% of cases. To investigate a possible correlation between weight and dose of thyroxine used, since small dogs have a higher metabolic rate than large dogs, the animals were grouped in Group A, dogs weighing <10 kg (n=12/30, 7.7±2.1 kg) and group B, dogs weighing> 10 kg (n=18/30, 26.8±10.7 kg). The mean dose of thyroxine used in groups A and B did not differ significantly and were respectively 16±3mg/kg and 17±3mg/kg. The frequency of administration was 50% every 24 hours and 50% every 12 hours for both groups. Thus, the dose of thyroxine does not seem to correlate with the weight of the animal being unpredictable who should receive the highest dose and frequency of the medication. The protocol should be individualized and the patient adequately monitored.