Marcadores de recambio óseo en mujeres postmenopáusicas: utilidad clínica / Bone remodelling markers in postmenopausal women: clinical utility

Bone metabolism is a dynamic process, which includes formation and resorption. Osteoblast and osteoclast are responsible of replacing 20 percent of bone each year. Bone Markers are fragments of bone matrix; these peptides are released in the process of formation and resorption, later accumulated in body compartments (bone and blood) and finally excreted in the urine, reflecting bone dynamic. The international Federation of Osteoporosis and the International Federation of Laboratory and Clinical Chemistry recommend the use of these two markers (one representing bone formation and the other bone resorption) to evaluate bone turnover, especially in high-risk groups such as postmenopausal women. The collagen C-terminal telopeptide or carboxi-terminal collagen crosslinking (CTX) is one of the most used, among different bone markers. This is a blood biomarker that can be measured to assess bone turnover; this marker increases when the bone resorption is accelerated. On the other hand, osteocalcin (a non-collagen protein) is a bone formation marker, which has been widely studied and can be measured in venous blood during bone formation. Both markers are important for monitoring anti-resorptive therapy, and they have been validated to predict fracture risk complementing densitometry in osteoporosis diagnosis. Main disadvantages are variability of the laboratory techniques and lack of information about normal reference values in different populations. Therefore it is necessary to establish normal reference values for each population before its incorporation as a clinical tool.

Análisis de factores de agresividad de microcarcinoma papilar de tiroides / Features influencing aggressiveness of papillary thyroid microcarcinoma

Background: the risk factors determining the aggressiveness of papillary thyroid microcarcinoma (PTMC) are not well known. Aim: to determine if tumor size, along with other features of the tumor, influences its prognosis. Patients and Methods: we analyzed the medical records of 147 patients (age range 16-92 years, 93 percent women) at the Clinical Hospital of University of Chile who underwent thyroid surgery and in whom at least one focus of PTMC was found. We determined the association between different clinical characteristics and the presence of capsular invasion, lymph nodal extension or recurrence. Results: a tumor size over 5 mm, a follicular subtype and being aged more than 45 years, were significantly associated with the presence of capsular invasion. The latter two variables were protective. In the multivariate analysis, only a tumor size over 5 mm was significantly associated with thyroid capsule involvement. Conclusions: a tumor size over 5 mm is associated with capsular invasion in PTMC.

Introducción: los factores de riesgo que determinan una conducta agresiva de microcarcinoma papilar de tiroides (MCPT) no se conocen. Nuestra hipótesis es que el tamaño del tumor, posiblemente junto con otras características del cáncer puede influir en el pronóstico de esta patología. Material y Método: se analizaron las historias clínicas de 147 pacientes que se sometieron en nuestro hospital a cirugía de tiroides y en los cuales se encontró al menos un foco de MCPT. Resultados: se determinó la existencia de una correlación entre las diferentes características clínicas y la presencia de invasión capsular, la extensión ganglionar linfático o la recidiva. En el análisis univariado, el tamaño del tumor mayor de 5 mm, se correlacionó significativamente con la presencia de invasión capsular (p < 0,05). Entre las variables estudiadas, sólo un tamaño superior a 5 mm se asoció significativamente con el compromiso de la cápsula tiroidea en el análisis multivariado. Conclusiones: aunque en general el MCPT se comportan con baja agresividad, se encontró que aquellos que son mayores de 5 mm a menudo tienen invasión capsular, que se ha relacionado con aumento de la agresividad y recidiva. Se recomienda un tratamiento orientado según la presencia de factores de riesgo como las que se describen aquí.

Enfermedad de graves en asociación con miastenia gravis: presentación de un caso y revisión de la literatura / Myasthenia gravis with concomitant hyperthyroidism: report of one case

Myasthenia gravis and Graves disease are autoimmune diseases that can coexist in the same patient. We report a 18 years old female with a history of myasthenia gravis diagnosed at the age of six, treated with neostigmine and prednisone. She starts with palpitations, dyspnea, proximal muscle weakness and exophthalmos appearing seven months after the onset of symptoms. She was admitted to the hospital due to her decompensated hyperthyroidism. After admission, she develops a myasthenic crisis, that requires mechanical ventilation. Afterwards, the patient is subjected to a thymectomy and thyroidectomy with a good postoperative evolution.

Prolactinoma gigante de inicio en la adolescencia: a propósito de 2 casos clínicos / Report of two adolecents with giant prolactinomas

The prevalence of pituitary among adolescents is 0.1 per million and the most common type is prolactinoma. We report two adolescents with pituitary adenomas. A 15 years old female presenting with a progressive reduction of visual acuity, headache and galactorrhea. Magnetic resonanceshowed a sellar tumor with suprasellar expansion. She was subjected to transcraneal surgery and the pathological study of the piece disclosed a prolactinoma. A 23 years old male presenting with weight gain, headache and decreased visual acuity of the left eye. Magnetic resonance demonstrateda tumor with sellar and suprasellar involvement. He was subjected to transsphenoidal surgery and the pathological study of the surgical piece disclosed a prolactinoma.

Alteraciones metabólicas asociadas al uso de terapia antipsicótica: [revisión] / Atypical antipsychotic induced weight gain and metabolic disorders: [revision]

The advent of new antipsychotic drugs has improved the treatment of schizophrenic patients as well as those suffering from other severe psychiatric disorders. Its widespread use, however, has been associated to the development of obesity and metabolic disturbances such as diabetes mellitus, dyslipidemia and increased coronary risk. This has caused a serious concern, due to the high cardiovascular mortality that prematurely affects these patients. The etiology of these abnormalities is still a matter of debate, although it is generally believed that the new antipsychotic drugs have a control stimulating effect on appetite, and their use is associated to an increased level of cortisol and to an insulin-resistance state. In addition, there is an increase in inflammatory mediator and cytokine production, induced by the pathophysiology of the schizophrenic process itself and also caused by the direct action of the antipsichotic drugs. In spite of the mounting evidence, the metabolic management of these patients is still deñcient. A cióse follow-up in the initial stages of the antipsychotic treatment is recommended, as well as giving advice about diet and physical exercise. Finally, when obesity or other conditions associated to metabolic syndrome appear, the recommendation is to switch to drugs with less secondary effects or to add adjuvant medications to improve the overall evolution of these patients.

Consenso elaborado por la Sociedad Chilena de Endocrinología y Diabetes sobre resistencia a la insulina(RI) y síndrome metabólico (SM): aspectos clínicos y terapéuticos / Chilean society of endocrinology and diabetes consensus on clinical and therapeutic aspects of insulin resistance and metabolic syndrome

Background: The concept insulin resistance as the basis for a series of metabolic alterations and diseases was introduced by Gerald Reaven in 1988, when he described a cluster of alterations that named syndrome X. Aim: To review and discuss the present information about insulin resistance (IR) and metabolic syndrome (MS). Material and methods: The IR concept is defined,the affected metabolic ways, its consequences and relationship with different diseases are presented. The importance of central obesity with its metabolic, inflammatory and prothrombotic consequences playing a key role in cardiovascular risk, is discussed. The cluster of factors focused on cardiovascular disease and eventually diabetes is named MS. Several definitions of MS are analyzed and compared. A proposition is made about the definition to be used in the Chilean population. Differences between IR syndrome and MS are discussed. Diagnostic methods of IR and MS are presented, recommendations are made about their usefulness and reliability. Non pharmacological and pharmacological treatments of IR and MS are analyzed. Other related diseases, such as polycystic ovary syndrome, non alcoholic steatohepatitis and sleep apnea are discussed. Conclusions. Until further studies are made to define a local waist circumference cut-off associated with high risk, the ATPIII MS definition is preferred. A clinical approach is recommended for diagnosis. A search for all components of the MS is important. There is no evidence about the benefits of MS treatment on the prevention of cardiovascular diseases or diabetes. Evidence supports the use of lifestyle changes and some drugs, such as metformin on the prevention of diabetes in prediabetic states.

Tiroides y depresión: enfoque terapéutico actual y bases moleculares / Thyroid and depression: actually and therapeutic approach and molecular basis

Depression is a serious and high-priority public health problem. In Chilean population, prevalence ranges from 5 to 27,3 percent. Therapy is based mainly in the use of selective serotonin reuptake inhibitors (SSRIs). Combination of thyroid hormone, sodium liothyronine, associated to traditional antidepressants to improve or accelerate therapeutic response is currently accepted. The use of this combination is based on hypothalamus-hypophysis-thyroid axis (HHT) alterations and on the peripheral conversion to active hormone, the triiodothyronine (T3), by type 2 and 3deiodinases (D2 and D3). Subtle changes in enzyme activity could have a strong impact in T3 brain availability. In major depression as high as a 25 percent of altered responses of HHT axis to the TRH stimulus may be observed. Certain polymorphisms of the D2 gene could be associated to enzyme activity changes. Isotopic studies are able to assess brain flow in diverse conditions, like global or specific regional perfusion variations in patients with mild hypothyroidism, pre and post T4 or SSRIs therapy in depressive patients.

Polimorfismo de la proteína ligante de ácidos grasos intestinal (FABP2), obesidad e insulina resistencia / Fatty acid binding protein 2 (FABP-2) polymorphism, obesity and insulin resistance

The genetic components of insulin-resistance, diabetes and obesity have been largely studied. These conditions are determined by multiple polygenic and environmental factors. Certain candidate genes, that have common functional variants in the general population, may be important determinants of inter-individual differences in the response to dietary changes. This review focuses in one of the major candidate genes, the gene encoding for the FABP2, an intracellular protein expressed only in the intestine, involved in the absorption and intracellular transport of dietary long chain fatty acids. Carriers of the Thr54 allele in FABP2 have a 2-fold greater affinity for long chain fatty acids than Ala54 carriers. The increased flux of dietary fatty acids (FA) into the circulation, among carriers of FABP2 Ala54Thr, supports a role of the polymorphism of this allele in the etiology of metabolic disorders. The frequencies of the polymorphism in different populations fluctuate between 18% and 40%. FABP2 Ala54Thr variant has been associated with an increased fasting insulin concentration, fasting fatty acid oxidation and reduced glucose uptake. This evidence, although not conclusive, sustains an association between FABP-2 genotype and metabolic abnormalities.

Cambios hormonales en la obesidad mórbida / Hormonal changes in the morbid obesity

La obesidad mórbida se asocia a múltiples cambios hormonales y metabólicos, la mayor parte de ellos se relacionan con el aumento masivo de la grasa corporal. El adipocito secreta sustancias con funciones locales y generales; éstas cumplen un rol fisiológico en el control de la ingesta y elbalance calórico. El tejido adiposointeractúa con el sistema nervioso central a través de varias hormonas adipocitarias. Por otra parte, el sistema digestivo produce varias sustancias que actúan sobre receptores hipotalámicos específicos que generan repuestas regulatorias del apetito y la ingesta alimentaria. Las hormonas tiroideasson habitualmente normales en los pacientes obesos con la excepción de T3 que puede estar elevada. La producción y metabolización de los corticoidessuprarrenales está aumentada. Sin embargo, los niveles de cortisol urinario son normales excepto en casos dehipercortisolismo endógeno. Los niveles de testosterona total pueden bajar en los pacientes con obesidad severa, pero la testosterona libre habitualmente es normal. Esto se explica por un descenso de la globulina transportadora de hormonas sexuales. En pacientes con obesidad mórbida severa (> 200 por ciento de sobrepeso) se puede producir una disminución de los niveles de testosterona libre. El sistema renina-angiotensina está activado en la obesidad severa. Sin embargo,los niveles de renina permanecen normales. Es importante conocer estos cambios no solo para hacer un diagnóstico diferencial con otras endocrinopatías sino para considerarpotenciales efectos patológicos. Lasendocrinopatías, primarias como elhipotiroidismo y el hiperadrenalismo endógeno no son habitualmente causa deobesidad mórbida.

La macroprolactina, diagnóstico diferencial de la hiperprolactinemia / The macroprolactina, differential diagnosis of the hyperprolactinaemia

La macroprolactina es una isoforma de la prolactina (PRL) humana que se encuentra en escasa proporción en el plasma y que en algunos pacientes se puede encontrar anormalmente elevada, causando hiperprolactinemia, que puede presentarse como asintomática, pero también presentar sintomatología dada por el exceso de prolactina, también ha sido relacionada a adenomas hipofisiarios. Por esta causa es necesario contar con métodos confiables para su detección y medición. El origen de esta macromolécula, patogenia, regulación hormonal e historia natural aun no está esclarecido, se postula que corresponde a un complejo antigénico IgG-PRL, con bioactibidad reducida.El Gold Standard para la determinación de la macroprolactina es la Cromatografía de filtración en gel, pero su uso se restringe a la investigación por su alto costo y tiempo de desarrollo. Existen otros métodos para su detección, siendo hasta ahora el de precipitación por Polietilenglicol el más aceptado.

Macroprolactin is an isoform of human prolactin (PRL) existing in low doses in plasma. In some patients, prolactine can be found in higher proportion, causing hyperprolactinaemia, in asyntomaticor symptomatic form. This abnormality has been also related to hypophysis adenome, doing necessary to count on reliable methods for its detection and measurement. The origin of this macromolecule, patogenia, hormonal regulation and natural history are not even clear, an antigenic complex IgG-PRL with reduced bioactivity is proposed. The Gold Standard for determination of macroprolactin is gel filtration chromatography, but its high costs and slowness restricts its use toresearch. Other methods for its detection already exist, the Polyethylene glycol precipitation is beingmostly accepted.

Consenso de diagnóstico y manejo de los nódulos tiroideos no palpables / Consensus report on the diagnosis and management of non palpable thyroid nodules

With the availability of new diagnostic techniques, numerous alterations are found, whose real importance for health is uncertain. The term <>, is used for non apparent tumors found in diagnostic procedures. In Endocrinology, the incidental finding of thyroid nodules is common. The occurrence of those incidental nodules requires a review of the <> statements for the management of palpable nodules. The most important issue is to rule out the presence of cancer. The Chilean Society of Endocrinology, Metabolism and Nutrition appointed a group of experts to generate a consensus on tbe management of non palpable nodules. These experts reviewed international literature, and the local experience, analyzed the value of thyroid ultrasound examination and the efficiency of fine needle aspiration biopsy. This consensus is a clinical guide for the management of non palpable thyroid nodules, considering that a unique and optimal approach is still lacking.

Prevención de diabetes mellitus tipo 2 / Prevention of type 2 diabetes mellitus

La Diabetes Mellitus tipo 2 presenta una importante morbilidad y mortalidad y una incidencia está en aumento, que se asocia al aumento observado en la prevalencia de la obesidad. Diversas medidas han sido evaluadas con el fin de retrasar o prevenir su aparición, entre las cuales se incluyen cambios en el estilo de vida, fármacos insulinosensibilizadores, e inhibidores de la absorción de carbohidratos y lípidos, con resultados esperanzadores. En la actualidad, los cambios en el estilo de vida, entendidos en el contexto de un apoyo multidisciplinario al paciente, constituyen la intervención de mayor impacto. Por otro lado, diversas clases de fármacos empleados en estudios de prevención de eventos cardiovasculares han demostrado cierto efecto en retrasar o prevenir la aparición de Diabetes Mellitus tipo 2, lo cual abre un nuevo escenario para los estudios que se desarrollarán en el mediano plazo.